backend/cos: Add TencentCloud backend cos with lock (#22540)

* add TencentCloud COS backend for remote state

* add vendor of dependence

* fixed error not handle and remove default value for prefix argument

* get appid from TF_COS_APPID environment variables

CODEOWNERS

@@ -5,3 +5,4 @@
 /backend/remote-state/azure     @hashicorp/terraform-azure
 /backend/remote-state/gcs       @hashicorp/terraform-google
 /backend/remote-state/s3        @hashicorp/terraform-aws
+/backend/remote-state/s3        @likexian
\ No newline at end of file

backend/init/init.go

@@ -16,6 +16,7 @@ import (
 	backendArtifactory "github.com/hashicorp/terraform/backend/remote-state/artifactory"
 	backendAzure "github.com/hashicorp/terraform/backend/remote-state/azure"
 	backendConsul "github.com/hashicorp/terraform/backend/remote-state/consul"
+	backendCos "github.com/hashicorp/terraform/backend/remote-state/cos"
 	backendEtcdv2 "github.com/hashicorp/terraform/backend/remote-state/etcdv2"
 	backendEtcdv3 "github.com/hashicorp/terraform/backend/remote-state/etcdv3"
 	backendGCS "github.com/hashicorp/terraform/backend/remote-state/gcs"
@@ -57,6 +58,7 @@ func Init(services *disco.Disco) {
 		"atlas":       func() backend.Backend { return backendAtlas.New() },
 		"azurerm":     func() backend.Backend { return backendAzure.New() },
 		"consul":      func() backend.Backend { return backendConsul.New() },
+		"cos":         func() backend.Backend { return backendCos.New() },
 		"etcd":        func() backend.Backend { return backendEtcdv2.New() },
 		"etcdv3":      func() backend.Backend { return backendEtcdv3.New() },
 		"gcs":         func() backend.Backend { return backendGCS.New() },

backend/init/init_test.go

@@ -18,6 +18,7 @@ func TestInit_backend(t *testing.T) {
 		{"atlas", "*atlas.Backend"},
 		{"azurerm", "*azure.Backend"},
 		{"consul", "*consul.Backend"},
+		{"cos", "*cos.Backend"},
 		{"etcdv3", "*etcd.Backend"},
 		{"gcs", "*gcs.Backend"},
 		{"inmem", "*inmem.Backend"},

backend/remote-state/cos/backend.go

+package cos
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common"
+	"github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common/profile"
+	tag "github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/tag/v20180813"
+	"github.com/tencentyun/cos-go-sdk-v5"
+)
+
+// Default value from environment variable
+const (
+	PROVIDER_SECRET_ID  = "TENCENTCLOUD_SECRET_ID"
+	PROVIDER_SECRET_KEY = "TENCENTCLOUD_SECRET_KEY"
+	PROVIDER_REGION     = "TENCENTCLOUD_REGION"
+)
+
+// Backend implements "backend".Backend for tencentCloud cos
+type Backend struct {
+	*schema.Backend
+
+	cosContext context.Context
+	cosClient  *cos.Client
+	tagClient  *tag.Client
+
+	region  string
+	bucket  string
+	prefix  string
+	key     string
+	encrypt bool
+	acl     string
+}
+
+// New creates a new backend for TencentCloud cos remote state.
+func New() backend.Backend {
+	s := &schema.Backend{
+		Schema: map[string]*schema.Schema{
+			"secret_id": {
+				Type:        schema.TypeString,
+				Required:    true,
+				DefaultFunc: schema.EnvDefaultFunc(PROVIDER_SECRET_ID, nil),
+				Description: "Secret id of Tencent Cloud",
+			},
+			"secret_key": {
+				Type:        schema.TypeString,
+				Required:    true,
+				DefaultFunc: schema.EnvDefaultFunc(PROVIDER_SECRET_KEY, nil),
+				Description: "Secret key of Tencent Cloud",
+				Sensitive:   true,
+			},
+			"region": {
+				Type:         schema.TypeString,
+				Required:     true,
+				DefaultFunc:  schema.EnvDefaultFunc(PROVIDER_REGION, nil),
+				Description:  "The region of the COS bucket",
+				InputDefault: "ap-guangzhou",
+			},
+			"bucket": {
+				Type:        schema.TypeString,
+				Required:    true,
+				Description: "The name of the COS bucket",
+			},
+			"prefix": {
+				Type:        schema.TypeString,
+				Optional:    true,
+				Description: "The directory for saving the state file in bucket",
+				ValidateFunc: func(v interface{}, s string) ([]string, []error) {
+					prefix := v.(string)
+					if strings.HasPrefix(prefix, "/") || strings.HasPrefix(prefix, "./") {
+						return nil, []error{fmt.Errorf("prefix must not start with '/' or './'")}
+					}
+					return nil, nil
+				},
+			},
+			"key": {
+				Type:        schema.TypeString,
+				Optional:    true,
+				Description: "The path for saving the state file in bucket",
+				Default:     "terraform.tfstate",
+				ValidateFunc: func(v interface{}, s string) ([]string, []error) {
+					if strings.HasPrefix(v.(string), "/") || strings.HasSuffix(v.(string), "/") {
+						return nil, []error{fmt.Errorf("key can not start and end with '/'")}
+					}
+					return nil, nil
+				},
+			},
+			"encrypt": {
+				Type:        schema.TypeBool,
+				Optional:    true,
+				Description: "Whether to enable server side encryption of the state file",
+				Default:     true,
+			},
+			"acl": {
+				Type:        schema.TypeString,
+				Optional:    true,
+				Description: "Object ACL to be applied to the state file",
+				Default:     "private",
+				ValidateFunc: func(v interface{}, s string) ([]string, []error) {
+					value := v.(string)
+					if value != "private" && value != "public-read" {
+						return nil, []error{fmt.Errorf(
+							"acl value invalid, expected %s or %s, got %s",
+							"private", "public-read", value)}
+					}
+					return nil, nil
+				},
+			},
+		},
+	}
+
+	result := &Backend{Backend: s}
+	result.Backend.ConfigureFunc = result.configure
+
+	return result
+}
+
+// configure init cos client
+func (b *Backend) configure(ctx context.Context) error {
+	if b.cosClient != nil {
+		return nil
+	}
+
+	b.cosContext = ctx
+	data := schema.FromContextBackendConfig(b.cosContext)
+
+	b.region = data.Get("region").(string)
+	b.bucket = data.Get("bucket").(string)
+	b.prefix = data.Get("prefix").(string)
+	b.key = data.Get("key").(string)
+	b.encrypt = data.Get("encrypt").(bool)
+	b.acl = data.Get("acl").(string)
+
+	u, err := url.Parse(fmt.Sprintf("https://%s.cos.%s.myqcloud.com", b.bucket, b.region))
+	if err != nil {
+		return err
+	}
+
+	b.cosClient = cos.NewClient(
+		&cos.BaseURL{BucketURL: u},
+		&http.Client{
+			Timeout: 60 * time.Second,
+			Transport: &cos.AuthorizationTransport{
+				SecretID:  data.Get("secret_id").(string),
+				SecretKey: data.Get("secret_key").(string),
+			},
+		},
+	)
+
+	credential := common.NewCredential(
+		data.Get("secret_id").(string),
+		data.Get("secret_key").(string),
+	)
+
+	cpf := profile.NewClientProfile()
+	cpf.HttpProfile.ReqMethod = "POST"
+	cpf.HttpProfile.ReqTimeout = 300
+	cpf.Language = "en-US"
+	b.tagClient, err = tag.NewClient(credential, b.region, cpf)
+
+	return err
+}

backend/remote-state/cos/backend_state.go

+package cos
+
+import (
+	"fmt"
+	"log"
+	"path"
+	"sort"
+	"strings"
+
+	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/state"
+	"github.com/hashicorp/terraform/state/remote"
+	"github.com/hashicorp/terraform/states"
+	"github.com/likexian/gokit/assert"
+)
+
+// Define file suffix
+const (
+	stateFileSuffix = ".tfstate"
+	lockFileSuffix  = ".tflock"
+)
+
+// Workspaces returns a list of names for the workspaces
+func (b *Backend) Workspaces() ([]string, error) {
+	c, err := b.client("tencentcloud")
+	if err != nil {
+		return nil, err
+	}
+
+	obs, err := c.getBucket(b.prefix)
+	log.Printf("[DEBUG] list all workspaces, objects: %v, error: %v", obs, err)
+	if err != nil {
+		return nil, err
+	}
+
+	ws := []string{backend.DefaultStateName}
+	for _, vv := range obs {
+		// <name>.tfstate
+		if !strings.HasSuffix(vv.Key, stateFileSuffix) {
+			continue
+		}
+		// default worksapce
+		if path.Join(b.prefix, b.key) == vv.Key {
+			continue
+		}
+		// <prefix>/<worksapce>/<key>
+		prefix := strings.TrimRight(b.prefix, "/") + "/"
+		parts := strings.Split(strings.TrimPrefix(vv.Key, prefix), "/")
+		if len(parts) > 0 && parts[0] != "" {
+			ws = append(ws, parts[0])
+		}
+	}
+
+	sort.Strings(ws[1:])
+	log.Printf("[DEBUG] list all workspaces, workspaces: %v", ws)
+
+	return ws, nil
+}
+
+// DeleteWorkspace deletes the named workspaces. The "default" state cannot be deleted.
+func (b *Backend) DeleteWorkspace(name string) error {
+	log.Printf("[DEBUG] delete workspace, workspace: %v", name)
+
+	if name == backend.DefaultStateName || name == "" {
+		return fmt.Errorf("default state is not allow to delete")
+	}
+
+	c, err := b.client(name)
+	if err != nil {
+		return err
+	}
+
+	return c.Delete()
+}
+
+// StateMgr manage the state, if the named state not exists, a new file will created
+func (b *Backend) StateMgr(name string) (state.State, error) {
+	log.Printf("[DEBUG] state manager, current workspace: %v", name)
+
+	c, err := b.client(name)
+	if err != nil {
+		return nil, err
+	}
+	stateMgr := &remote.State{Client: c}
+
+	ws, err := b.Workspaces()
+	if err != nil {
+		return nil, err
+	}
+
+	if !assert.IsContains(ws, name) {
+		log.Printf("[DEBUG] workspace %v not exists", name)
+
+		// take a lock on this state while we write it
+		lockInfo := state.NewLockInfo()
+		lockInfo.Operation = "init"
+		lockId, err := c.Lock(lockInfo)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to lock cos state: %s", err)
+		}
+
+		// Local helper function so we can call it multiple places
+		lockUnlock := func(e error) error {
+			if err := stateMgr.Unlock(lockId); err != nil {
+				return fmt.Errorf(unlockErrMsg, err, lockId)
+			}
+			return e
+		}
+
+		// Grab the value
+		if err := stateMgr.RefreshState(); err != nil {
+			err = lockUnlock(err)
+			return nil, err
+		}
+
+		// If we have no state, we have to create an empty state
+		if v := stateMgr.State(); v == nil {
+			if err := stateMgr.WriteState(states.NewState()); err != nil {
+				err = lockUnlock(err)
+				return nil, err
+			}
+			if err := stateMgr.PersistState(); err != nil {
+				err = lockUnlock(err)
+				return nil, err
+			}
+		}
+
+		// Unlock, the state should now be initialized
+		if err := lockUnlock(nil); err != nil {
+			return nil, err
+		}
+	}
+
+	return stateMgr, nil
+}
+
+// client returns a remoteClient for the named state.
+func (b *Backend) client(name string) (*remoteClient, error) {
+	if strings.TrimSpace(name) == "" {
+		return nil, fmt.Errorf("state name not allow to be empty")
+	}
+
+	return &remoteClient{
+		cosContext: b.cosContext,
+		cosClient:  b.cosClient,
+		tagClient:  b.tagClient,
+		bucket:     b.bucket,
+		stateFile:  b.stateFile(name),
+		lockFile:   b.lockFile(name),
+		encrypt:    b.encrypt,
+		acl:        b.acl,
+	}, nil
+}
+
+// stateFile returns state file path by name
+func (b *Backend) stateFile(name string) string {
+	if name == backend.DefaultStateName {
+		return path.Join(b.prefix, b.key)
+	}
+	return path.Join(b.prefix, name, b.key)
+}
+
+// lockFile returns lock file path by name
+func (b *Backend) lockFile(name string) string {
+	return b.stateFile(name) + lockFileSuffix
+}
+
+// unlockErrMsg is error msg for unlock failed
+const unlockErrMsg = `
+Unlocking the state file on TencentCloud cos backend failed:
+
+Error message: %v
+Lock ID (gen): %s
+
+You may have to force-unlock this state in order to use it again.
+The TencentCloud backend acquires a lock during initialization
+to ensure the initial state file is created.
+`

backend/remote-state/cos/backend_test.go

+package cos
+
+import (
+	"crypto/md5"
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/state/remote"
+	"github.com/likexian/gokit/assert"
+)
+
+const (
+	defaultPrefix = ""
+	defaultKey    = "terraform.tfstate"
+)
+
+// Testing Thanks to GCS
+
+func TestStateFile(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		prefix        string
+		stateName     string
+		key           string
+		wantStateFile string
+		wantLockFile  string
+	}{
+		{"", "default", "default.tfstate", "default.tfstate", "default.tfstate.tflock"},
+		{"", "default", "test.tfstate", "test.tfstate", "test.tfstate.tflock"},
+		{"", "dev", "test.tfstate", "dev/test.tfstate", "dev/test.tfstate.tflock"},
+		{"terraform/test", "default", "default.tfstate", "terraform/test/default.tfstate", "terraform/test/default.tfstate.tflock"},
+		{"terraform/test", "default", "test.tfstate", "terraform/test/test.tfstate", "terraform/test/test.tfstate.tflock"},
+		{"terraform/test", "dev", "test.tfstate", "terraform/test/dev/test.tfstate", "terraform/test/dev/test.tfstate.tflock"},
+	}
+
+	for _, c := range cases {
+		b := &Backend{
+			prefix: c.prefix,
+			key:    c.key,
+		}
+		assert.Equal(t, b.stateFile(c.stateName), c.wantStateFile)
+		assert.Equal(t, b.lockFile(c.stateName), c.wantLockFile)
+	}
+}
+
+func TestRemoteClient(t *testing.T) {
+	t.Parallel()
+
+	bucket := bucketName(t)
+
+	be := setupBackend(t, bucket, defaultPrefix, defaultKey, false)
+	defer teardownBackend(t, be)
+
+	ss, err := be.StateMgr(backend.DefaultStateName)
+	assert.Nil(t, err)
+
+	rs, ok := ss.(*remote.State)
+	assert.True(t, ok)
+
+	remote.TestClient(t, rs.Client)
+}
+
+func TestRemoteClientWithPrefix(t *testing.T) {
+	t.Parallel()
+
+	prefix := "prefix/test"
+	bucket := bucketName(t)
+
+	be := setupBackend(t, bucket, prefix, defaultKey, false)
+	defer teardownBackend(t, be)
+
+	ss, err := be.StateMgr(backend.DefaultStateName)
+	assert.Nil(t, err)
+
+	rs, ok := ss.(*remote.State)
+	assert.True(t, ok)
+
+	remote.TestClient(t, rs.Client)
+}
+
+func TestRemoteClientWithEncryption(t *testing.T) {
+	t.Parallel()
+
+	bucket := bucketName(t)
+
+	be := setupBackend(t, bucket, defaultPrefix, defaultKey, true)
+	defer teardownBackend(t, be)
+
+	ss, err := be.StateMgr(backend.DefaultStateName)
+	assert.Nil(t, err)
+
+	rs, ok := ss.(*remote.State)
+	assert.True(t, ok)
+
+	remote.TestClient(t, rs.Client)
+}
+
+func TestRemoteLocks(t *testing.T) {
+	t.Parallel()
+
+	bucket := bucketName(t)
+
+	be := setupBackend(t, bucket, defaultPrefix, defaultKey, false)
+	defer teardownBackend(t, be)
+
+	remoteClient := func() (remote.Client, error) {
+		ss, err := be.StateMgr(backend.DefaultStateName)
+		if err != nil {
+			return nil, err
+		}
+
+		rs, ok := ss.(*remote.State)
+		if !ok {
+			return nil, fmt.Errorf("be.StateMgr(): got a %T, want a *remote.State", ss)
+		}
+
+		return rs.Client, nil
+	}
+
+	c0, err := remoteClient()
+	assert.Nil(t, err)
+
+	c1, err := remoteClient()
+	assert.Nil(t, err)
+
+	remote.TestRemoteLocks(t, c0, c1)
+}
+
+func TestBackend(t *testing.T) {
+	t.Parallel()
+
+	bucket := bucketName(t)
+
+	be0 := setupBackend(t, bucket, defaultPrefix, defaultKey, false)
+	defer teardownBackend(t, be0)
+
+	be1 := setupBackend(t, bucket, defaultPrefix, defaultKey, false)
+	defer teardownBackend(t, be1)
+
+	backend.TestBackendStates(t, be0)
+	backend.TestBackendStateLocks(t, be0, be1)
+	backend.TestBackendStateForceUnlock(t, be0, be1)
+}
+
+func TestBackendWithPrefix(t *testing.T) {
+	t.Parallel()
+
+	prefix := "prefix/test"
+	bucket := bucketName(t)
+
+	be0 := setupBackend(t, bucket, prefix, defaultKey, false)
+	defer teardownBackend(t, be0)
+
+	be1 := setupBackend(t, bucket, prefix+"/", defaultKey, false)
+	defer teardownBackend(t, be1)
+
+	backend.TestBackendStates(t, be0)
+	backend.TestBackendStateLocks(t, be0, be1)
+}
+
+func TestBackendWithEncryption(t *testing.T) {
+	t.Parallel()
+
+	bucket := bucketName(t)
+
+	be0 := setupBackend(t, bucket, defaultPrefix, defaultKey, true)
+	defer teardownBackend(t, be0)
+
+	be1 := setupBackend(t, bucket, defaultPrefix, defaultKey, true)
+	defer teardownBackend(t, be1)
+
+	backend.TestBackendStates(t, be0)
+	backend.TestBackendStateLocks(t, be0, be1)
+}
+
+func setupBackend(t *testing.T, bucket, prefix, key string, encrypt bool) backend.Backend {
+	t.Helper()
+
+	skip := os.Getenv("TF_COS_APPID") == ""
+	if skip {
+		t.Skip("This test require setting TF_COS_APPID environment variables")
+	}
+
+	if os.Getenv(PROVIDER_REGION) == "" {
+		os.Setenv(PROVIDER_REGION, "ap-guangzhou")
+	}
+
+	appId := os.Getenv("TF_COS_APPID")
+	region := os.Getenv(PROVIDER_REGION)
+
+	config := map[string]interface{}{
+		"region": region,
+		"bucket": bucket + appId,
+		"prefix": prefix,
+		"key":    key,
+	}
+
+	b := backend.TestBackendConfig(t, New(), backend.TestWrapConfig(config))
+	be := b.(*Backend)
+
+	c, err := be.client("tencentcloud")
+	assert.Nil(t, err)
+
+	err = c.putBucket()
+	assert.Nil(t, err)
+
+	return b
+}
+
+func teardownBackend(t *testing.T, b backend.Backend) {
+	t.Helper()
+
+	c, err := b.(*Backend).client("tencentcloud")
+	assert.Nil(t, err)
+
+	err = c.deleteBucket(true)
+	assert.Nil(t, err)
+}
+
+func bucketName(t *testing.T) string {
+	unique := fmt.Sprintf("%s-%x", t.Name(), time.Now().UnixNano())
+	return fmt.Sprintf("terraform-test-%s-%s", fmt.Sprintf("%x", md5.Sum([]byte(unique)))[:10], "")
+}

backend/remote-state/cos/client.go

+package cos
+
+import (
+	"bytes"
+	"context"
+	"crypto/md5"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"strings"
+	"time"
+
+	multierror "github.com/hashicorp/go-multierror"
+	"github.com/hashicorp/terraform/state"
+	"github.com/hashicorp/terraform/state/remote"
+	tag "github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/tag/v20180813"
+	"github.com/tencentyun/cos-go-sdk-v5"
+)
+
+const (
+	lockTagKey = "tencentcloud-terraform-lock"
+)
+
+// RemoteClient implements the client of remote state
+type remoteClient struct {
+	cosContext context.Context
+	cosClient  *cos.Client
+	tagClient  *tag.Client
+
+	bucket    string
+	stateFile string
+	lockFile  string
+	encrypt   bool
+	acl       string
+}
+
+// Get returns remote state file
+func (c *remoteClient) Get() (*remote.Payload, error) {
+	log.Printf("[DEBUG] get remote state file %s", c.stateFile)
+
+	exists, data, checksum, err := c.getObject(c.stateFile)
+	if err != nil {
+		return nil, err
+	}
+
+	if !exists {
+		return nil, nil
+	}
+
+	payload := &remote.Payload{
+		Data: data,
+		MD5:  []byte(checksum),
+	}
+
+	return payload, nil
+}
+
+// Put put state file to remote
+func (c *remoteClient) Put(data []byte) error {
+	log.Printf("[DEBUG] put remote state file %s", c.stateFile)
+
+	return c.putObject(c.stateFile, data)
+}
+
+// Delete delete remote state file
+func (c *remoteClient) Delete() error {
+	log.Printf("[DEBUG] delete remote state file %s", c.stateFile)
+
+	return c.deleteObject(c.stateFile)
+}
+
+// Lock lock remote state file for writing
+func (c *remoteClient) Lock(info *state.LockInfo) (string, error) {
+	log.Printf("[DEBUG] lock remote state file %s", c.lockFile)
+
+	err := c.cosLock(c.bucket, c.lockFile)
+	if err != nil {
+		return "", c.lockError(err)
+	}
+	defer c.cosUnlock(c.bucket, c.lockFile)
+
+	exists, _, _, err := c.getObject(c.lockFile)
+	if err != nil {
+		return "", c.lockError(err)
+	}
+
+	if exists {
+		return "", c.lockError(fmt.Errorf("lock file %s exists", c.lockFile))
+	}
+
+	info.Path = c.lockFile
+	data, err := json.Marshal(info)
+	if err != nil {
+		return "", c.lockError(err)
+	}
+
+	check := fmt.Sprintf("%x", md5.Sum(data))
+	err = c.putObject(c.lockFile, data)
+	if err != nil {
+		return "", c.lockError(err)
+	}
+
+	return check, nil
+}
+
+// Unlock unlock remote state file
+func (c *remoteClient) Unlock(check string) error {
+	log.Printf("[DEBUG] unlock remote state file %s", c.lockFile)
+
+	info, err := c.lockInfo()
+	if err != nil {
+		return c.lockError(err)
+	}
+
+	if info.ID != check {
+		return c.lockError(fmt.Errorf("lock id mismatch, %v != %v", info.ID, check))
+	}
+
+	err = c.deleteObject(c.lockFile)
+	if err != nil {
+		return c.lockError(err)
+	}
+
+	return nil
+}
+
+// lockError returns state.LockError
+func (c *remoteClient) lockError(err error) *state.LockError {
+	log.Printf("[DEBUG] failed to lock or unlock %s: %v", c.lockFile, err)
+
+	lockErr := &state.LockError{
+		Err: err,
+	}
+
+	info, infoErr := c.lockInfo()
+	if infoErr != nil {
+		lockErr.Err = multierror.Append(lockErr.Err, infoErr)
+	} else {
+		lockErr.Info = info
+	}
+
+	return lockErr
+}
+
+// lockInfo returns LockInfo from lock file
+func (c *remoteClient) lockInfo() (*state.LockInfo, error) {
+	exists, data, checksum, err := c.getObject(c.lockFile)
+	if err != nil {
+		return nil, err
+	}
+
+	if !exists {
+		return nil, fmt.Errorf("lock file %s not exists", c.lockFile)
+	}
+
+	info := &state.LockInfo{}
+	if err := json.Unmarshal(data, info); err != nil {
+		return nil, err
+	}
+
+	info.ID = checksum
+
+	return info, nil
+}
+
+// getObject get remote object
+func (c *remoteClient) getObject(cosFile string) (exists bool, data []byte, checksum string, err error) {
+	rsp, err := c.cosClient.Object.Get(c.cosContext, cosFile, nil)
+	if rsp == nil {
+		log.Printf("[DEBUG] getObject %s: error: %v", cosFile, err)
+		err = fmt.Errorf("failed to open file at %v: %v", cosFile, err)
+		return
+	}
+	defer rsp.Body.Close()
+
+	log.Printf("[DEBUG] getObject %s: code: %d, error: %v", cosFile, rsp.StatusCode, err)
+	if err != nil {
+		if rsp.StatusCode == 404 {
+			err = nil
+		} else {
+			err = fmt.Errorf("failed to open file at %v: %v", cosFile, err)
+		}
+		return
+	}
+
+	checksum = rsp.Header.Get("X-Cos-Meta-Md5")
+	log.Printf("[DEBUG] getObject %s: checksum: %s", cosFile, checksum)
+	if len(checksum) != 32 {
+		err = fmt.Errorf("failed to open file at %v: checksum %s invalid", cosFile, checksum)
+		return
+	}
+
+	exists = true
+	data, err = ioutil.ReadAll(rsp.Body)
+	log.Printf("[DEBUG] getObject %s: data length: %d", cosFile, len(data))
+	if err != nil {
+		err = fmt.Errorf("failed to open file at %v: %v", cosFile, err)
+		return
+	}
+
+	check := fmt.Sprintf("%x", md5.Sum(data))
+	log.Printf("[DEBUG] getObject %s: check: %s", cosFile, check)
+	if check != checksum {
+		err = fmt.Errorf("failed to open file at %v: checksum mismatch, %s != %s", cosFile, check, checksum)
+		return
+	}
+
+	return
+}
+
+// putObject put object to remote
+func (c *remoteClient) putObject(cosFile string, data []byte) error {
+	opt := &cos.ObjectPutOptions{
+		ObjectPutHeaderOptions: &cos.ObjectPutHeaderOptions{
+			XCosMetaXXX: &http.Header{
+				"X-Cos-Meta-Md5": []string{fmt.Sprintf("%x", md5.Sum(data))},
+			},
+		},
+		ACLHeaderOptions: &cos.ACLHeaderOptions{
+			XCosACL: c.acl,
+		},
+	}
+
+	if c.encrypt {
+		opt.ObjectPutHeaderOptions.XCosServerSideEncryption = "AES256"
+	}
+
+	r := bytes.NewReader(data)
+	rsp, err := c.cosClient.Object.Put(c.cosContext, cosFile, r, opt)
+	if rsp == nil {
+		log.Printf("[DEBUG] putObject %s: error: %v", cosFile, err)
+		return fmt.Errorf("failed to save file to %v: %v", cosFile, err)
+	}
+	defer rsp.Body.Close()
+
+	log.Printf("[DEBUG] putObject %s: code: %d, error: %v", cosFile, rsp.StatusCode, err)
+	if err != nil {
+		return fmt.Errorf("failed to save file to %v: %v", cosFile, err)
+	}
+
+	return nil
+}
+
+// deleteObject delete remote object
+func (c *remoteClient) deleteObject(cosFile string) error {
+	rsp, err := c.cosClient.Object.Delete(c.cosContext, cosFile)
+	if rsp == nil {
+		log.Printf("[DEBUG] deleteObject %s: error: %v", cosFile, err)
+		return fmt.Errorf("failed to delete file %v: %v", cosFile, err)
+	}
+	defer rsp.Body.Close()
+
+	log.Printf("[DEBUG] deleteObject %s: code: %d, error: %v", cosFile, rsp.StatusCode, err)
+	if rsp.StatusCode == 404 {
+		return nil
+	}
+
+	if err != nil {
+		return fmt.Errorf("failed to delete file %v: %v", cosFile, err)
+	}
+
+	return nil
+}
+
+// getBucket list bucket by prefix
+func (c *remoteClient) getBucket(prefix string) (obs []cos.Object, err error) {
+	fs, rsp, err := c.cosClient.Bucket.Get(c.cosContext, &cos.BucketGetOptions{Prefix: prefix})
+	if rsp == nil {
+		log.Printf("[DEBUG] getBucket %s/%s: error: %v", c.bucket, prefix, err)
+		err = fmt.Errorf("bucket %s not exists", c.bucket)
+		return
+	}
+	defer rsp.Body.Close()
+
+	log.Printf("[DEBUG] getBucket %s/%s: code: %d, error: %v", c.bucket, prefix, rsp.StatusCode, err)
+	if rsp.StatusCode == 404 {
+		err = fmt.Errorf("bucket %s not exists", c.bucket)
+		return
+	}
+
+	if err != nil {
+		return
+	}
+
+	return fs.Contents, nil
+}
+
+// putBucket create cos bucket
+func (c *remoteClient) putBucket() error {
+	rsp, err := c.cosClient.Bucket.Put(c.cosContext, nil)
+	if rsp == nil {
+		log.Printf("[DEBUG] putBucket %s: error: %v", c.bucket, err)
+		return fmt.Errorf("failed to create bucket %v: %v", c.bucket, err)
+	}
+	defer rsp.Body.Close()
+
+	log.Printf("[DEBUG] putBucket %s: code: %d, error: %v", c.bucket, rsp.StatusCode, err)
+	if rsp.StatusCode == 409 {
+		return nil
+	}
+
+	if err != nil {
+		return fmt.Errorf("failed to create bucket %v: %v", c.bucket, err)
+	}
+
+	return nil
+}
+
+// deleteBucket delete cos bucket
+func (c *remoteClient) deleteBucket(recursive bool) error {
+	if recursive {
+		obs, err := c.getBucket("")
+		if err != nil {
+			if strings.Contains(err.Error(), "not exists") {
+				return nil
+			}
+			log.Printf("[DEBUG] deleteBucket %s: empty bucket error: %v", c.bucket, err)
+			return fmt.Errorf("failed to empty bucket %v: %v", c.bucket, err)
+		}
+		for _, v := range obs {
+			c.deleteObject(v.Key)
+		}
+	}
+
+	rsp, err := c.cosClient.Bucket.Delete(c.cosContext)
+	if rsp == nil {
+		log.Printf("[DEBUG] deleteBucket %s: error: %v", c.bucket, err)
+		return fmt.Errorf("failed to delete bucket %v: %v", c.bucket, err)
+	}
+	defer rsp.Body.Close()
+
+	log.Printf("[DEBUG] deleteBucket %s: code: %d, error: %v", c.bucket, rsp.StatusCode, err)
+	if rsp.StatusCode == 404 {
+		return nil
+	}
+
+	if err != nil {
+		return fmt.Errorf("failed to delete bucket %v: %v", c.bucket, err)
+	}
+
+	return nil
+}
+
+// cosLock lock cos for writing
+func (c *remoteClient) cosLock(bucket, cosFile string) error {
+	log.Printf("[DEBUG] lock cos file %s:%s", bucket, cosFile)
+
+	cosPath := fmt.Sprintf("%s:%s", bucket, cosFile)
+	lockTagValue := fmt.Sprintf("%x", md5.Sum([]byte(cosPath)))
+
+	return c.CreateTag(lockTagKey, lockTagValue)
+}
+
+// cosUnlock unlock cos writing
+func (c *remoteClient) cosUnlock(bucket, cosFile string) error {
+	log.Printf("[DEBUG] unlock cos file %s:%s", bucket, cosFile)
+
+	cosPath := fmt.Sprintf("%s:%s", bucket, cosFile)
+	lockTagValue := fmt.Sprintf("%x", md5.Sum([]byte(cosPath)))
+
+	var err error
+	for i := 0; i < 30; i++ {
+		err = c.DeleteTag(lockTagKey, lockTagValue)
+		if err == nil {
+			return nil
+		}
+		time.Sleep(1 * time.Second)
+	}
+
+	return err
+}
+
+// CreateTag create tag by key and value
+func (c *remoteClient) CreateTag(key, value string) error {
+	request := tag.NewCreateTagRequest()
+	request.TagKey = &key
+	request.TagValue = &value
+
+	_, err := c.tagClient.CreateTag(request)
+	log.Printf("[DEBUG] create tag %s:%s: error: %v", key, value, err)
+	if err != nil {
+		return fmt.Errorf("failed to create tag: %s -> %s: %s", key, value, err)
+	}
+
+	return nil
+}
+
+// DeleteTag create tag by key and value
+func (c *remoteClient) DeleteTag(key, value string) error {
+	request := tag.NewDeleteTagRequest()
+	request.TagKey = &key
+	request.TagValue = &value
+
+	_, err := c.tagClient.DeleteTag(request)
+	log.Printf("[DEBUG] delete tag %s:%s: error: %v", key, value, err)
+	if err != nil {
+		return fmt.Errorf("failed to delete tag: %s -> %s: %s", key, value, err)
+	}
+
+	return nil
+}

go.mod

@@ -84,6 +84,7 @@ require (
 	github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0
 	github.com/keybase/go-crypto v0.0.0-20161004153544-93f5b35093ba // indirect
 	github.com/lib/pq v1.0.0
+	github.com/likexian/gokit v0.20.15
 	github.com/lusis/go-artifactory v0.0.0-20160115162124-7e4ce345df82
 	github.com/masterzen/winrm v0.0.0-20190223112901-5e5c9a7fe54b
 	github.com/mattn/go-colorable v0.1.1
@@ -113,6 +114,8 @@ require (
 	github.com/smartystreets/goconvey v0.0.0-20180222194500-ef6db91d284a // indirect
 	github.com/soheilhy/cmux v0.1.4 // indirect
 	github.com/spf13/afero v1.2.1
+	github.com/tencentcloud/tencentcloud-sdk-go v3.0.82+incompatible
+	github.com/tencentyun/cos-go-sdk-v5 v0.0.0-20190808065407-f07404cefc8c
 	github.com/terraform-providers/terraform-provider-openstack v1.15.0
 	github.com/tmc/grpc-websocket-proxy v0.0.0-20171017195756-830351dc03c6 // indirect
 	github.com/ugorji/go v0.0.0-20180813092308-00b869d2f4a5 // indirect

go.sum

@@ -41,6 +41,7 @@ github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/ChrisTrenkamp/goxpath v0.0.0-20170922090931-c385f95c6022 h1:y8Gs8CzNfDF5AZvjr+5UyGQvQEBL7pwo+v+wX6q9JI8=
 github.com/ChrisTrenkamp/goxpath v0.0.0-20170922090931-c385f95c6022/go.mod h1:nuWgzSkT5PnyOd+272uUmV0dnAnAn42Mk7PiQC5VzN4=
+github.com/QcloudApi/qcloud_sign_golang v0.0.0-20141224014652-e4130a326409/go.mod h1:1pk82RBxDY/JZnPQrtqHlUFfCctgdorsd9M06fMynOM=
 github.com/Unknwon/com v0.0.0-20151008135407-28b053d5a292 h1:tuQ7w+my8a8mkwN7x2TSd7OzTjkZ7rAeSyH4xncuAMI=
 github.com/Unknwon/com v0.0.0-20151008135407-28b053d5a292/go.mod h1:KYCjqMOeHpNuTOiFQU6WEcTG7poCJrUs0YgyHNtn1no=
 github.com/abdullin/seq v0.0.0-20160510034733-d5467c17e7af h1:DBNMBMuMiWYu0b+8KMJuWmfCkcxl09JwdlqwDZZ6U14=
@@ -285,6 +286,14 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/lib/pq v1.0.0 h1:X5PMW56eZitiTeO7tKzZxFCSpbFZJtkMMooicw2us9A=
 github.com/lib/pq v1.0.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
+github.com/likexian/gokit v0.0.0-20190309162924-0a377eecf7aa/go.mod h1:QdfYv6y6qPA9pbBA2qXtoT8BMKha6UyNbxWGWl/9Jfk=
+github.com/likexian/gokit v0.0.0-20190418170008-ace88ad0983b/go.mod h1:KKqSnk/VVSW8kEyO2vVCXoanzEutKdlBAPohmGXkxCk=
+github.com/likexian/gokit v0.0.0-20190501133040-e77ea8b19cdc/go.mod h1:3kvONayqCaj+UgrRZGpgfXzHdMYCAO0KAt4/8n0L57Y=
+github.com/likexian/gokit v0.20.15 h1:DgtIqqTRFqtbiLJFzuRESwVrxWxfs8OlY6hnPYBa3BM=
+github.com/likexian/gokit v0.20.15/go.mod h1:kn+nTv3tqh6yhor9BC4Lfiu58SmH8NmQ2PmEl+uM6nU=
+github.com/likexian/simplejson-go v0.0.0-20190409170913-40473a74d76d/go.mod h1:Typ1BfnATYtZ/+/shXfFYLrovhFyuKvzwrdOnIDHlmg=
+github.com/likexian/simplejson-go v0.0.0-20190419151922-c1f9f0b4f084/go.mod h1:U4O1vIJvIKwbMZKUJ62lppfdvkCdVd2nfMimHK81eec=
+github.com/likexian/simplejson-go v0.0.0-20190502021454-d8787b4bfa0b/go.mod h1:3BWwtmKP9cXWwYCr5bkoVDEfLywacOv0s06OBEDpyt8=
 github.com/lusis/go-artifactory v0.0.0-20160115162124-7e4ce345df82 h1:wnfcqULT+N2seWf6y4yHzmi7GD2kNx4Ute0qArktD48=
 github.com/lusis/go-artifactory v0.0.0-20160115162124-7e4ce345df82/go.mod h1:y54tfGmO3NKssKveTEFFzH8C/akrSOy/iW9qEAUDV84=
 github.com/masterzen/simplexml v0.0.0-20160608183007-4572e39b1ab9 h1:SmVbOZFWAlyQshuMfOkiAx1f5oUTsOGG5IXplAEYeeM=
@@ -336,6 +345,8 @@ github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/reflect2 v1.0.1 h1:9f412s+6RmYXLWZSEzVVgPGK7C2PphHj5RJrvfx9AWI=
 github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
+github.com/mozillazg/go-httpheader v0.2.1 h1:geV7TrjbL8KXSyvghnFm+NyTux/hxwueTSrwhe88TQQ=
+github.com/mozillazg/go-httpheader v0.2.1/go.mod h1:jJ8xECTlalr6ValeXYdOF8fFUISeBAdw6E61aqQma60=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d h1:VhgPp6v9qf9Agr/56bj7Y/xa04UccTW04VP0Qed4vnQ=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d/go.mod h1:YUTz3bUH2ZwIWBy3CJBeOBEugqcmXREj14T+iG/4k4U=
@@ -392,6 +403,10 @@ github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/svanharmelen/jsonapi v0.0.0-20180618144545-0c0828c3f16d h1:Z4EH+5EffvBEhh37F0C0DnpklTMh00JOkjW5zK3ofBI=
 github.com/svanharmelen/jsonapi v0.0.0-20180618144545-0c0828c3f16d/go.mod h1:BSTlc8jOjh0niykqEGVXOLXdi9o0r0kR8tCYiMvjFgw=
+github.com/tencentcloud/tencentcloud-sdk-go v3.0.82+incompatible h1:5Td2b0yfaOvw9M9nZ5Oav6Li9bxUNxt4DgxMfIPpsa0=
+github.com/tencentcloud/tencentcloud-sdk-go v3.0.82+incompatible/go.mod h1:0PfYow01SHPMhKY31xa+EFz2RStxIqj6JFAJS+IkCi4=
+github.com/tencentyun/cos-go-sdk-v5 v0.0.0-20190808065407-f07404cefc8c h1:iRD1CqtWUjgEVEmjwTMbP1DMzz1HRytOsgx/rlw/vNs=
+github.com/tencentyun/cos-go-sdk-v5 v0.0.0-20190808065407-f07404cefc8c/go.mod h1:wk2XFUg6egk4tSDNZtXeKfe2G6690UVyt163PuUxBZk=
 github.com/terraform-providers/terraform-provider-openstack v1.15.0 h1:adpjqej+F8BAX9dHmuPF47sUIkgifeqBu6p7iCsyj0Y=
 github.com/terraform-providers/terraform-provider-openstack v1.15.0/go.mod h1:2aQ6n/BtChAl1y2S60vebhyJyZXBsuAI5G4+lHrT1Ew=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20171017195756-830351dc03c6 h1:lYIiVDtZnyTWlNwiAxLj0bbpTcx1BWCFhXjfsvmPdNc=

vendor/github.com/likexian/gokit/LICENSE

+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright 2012-2019 Li Kexian
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+   APPENDIX: Copyright 2012-2019 Li Kexian
+
+       https://www.likexian.com/

vendor/github.com/likexian/gokit/assert/README.md

+# GoKit - assert
+
+Assert kits for Golang development.
+
+## Installation
+
+    go get -u github.com/likexian/gokit
+
+## Importing
+
+    import (
+        "github.com/likexian/gokit/assert"
+    )
+
+## Documentation
+
+Visit the docs on [GoDoc](https://godoc.org/github.com/likexian/gokit/assert)
+
+## Example
+
+### assert panic
+
+```go
+func willItPanic() {
+    panic("failed")
+}
+assert.Panic(t, willItPanic)
+```
+
+### assert err is nil
+
+```go
+fp, err := os.Open("/data/dev/gokit/LICENSE")
+assert.Nil(t, err)
+```
+
+### assert equal
+
+```go
+x := map[string]int{"a": 1, "b": 2}
+y := map[string]int{"a": 1, "b": 2}
+assert.Equal(t, x, y, "x shall equal to y")
+```
+
+### check string in array
+
+```go
+ok := assert.IsContains([]string{"a", "b", "c"}, "b")
+if ok {
+    fmt.Println("value in array")
+} else {
+    fmt.Println("value not in array")
+}
+```
+
+### check string in interface array
+
+```go
+ok := assert.IsContains([]interface{}{0, "1", 2}, "1")
+if ok {
+    fmt.Println("value in array")
+} else {
+    fmt.Println("value not in array")
+}
+```
+
+### check object in struct array
+
+```go
+ok := assert.IsContains([]A{A{0, 1}, A{1, 2}, A{1, 3}}, A{1, 2})
+if ok {
+    fmt.Println("value in array")
+} else {
+    fmt.Println("value not in array")
+}
+```
+
+### a := c ? x : y
+
+```go
+a := 1
+// b := a == 1 ? true : false
+b := assert.If(a == 1, true, false)
+```
+
+## LICENSE
+
+Copyright 2012-2019 Li Kexian
+
+Licensed under the Apache License 2.0
+
+## About
+
+- [Li Kexian](https://www.likexian.com/)
+
+## DONATE
+
+- [Help me make perfect](https://www.likexian.com/donate/)

vendor/github.com/likexian/gokit/assert/assert.go

+/*
+ * Copyright 2012-2019 Li Kexian
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * A toolkit for Golang development
+ * https://www.likexian.com/
+ */
+
+package assert
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+// Version returns package version
+func Version() string {
+	return "0.10.1"
+}
+
+// Author returns package author
+func Author() string {
+	return "[Li Kexian](https://www.likexian.com/)"
+}
+
+// License returns package license
+func License() string {
+	return "Licensed under the Apache License 2.0"
+}
+
+// Equal assert test value to be equal
+func Equal(t *testing.T, got, exp interface{}, args ...interface{}) {
+	equal(t, got, exp, 1, args...)
+}
+
+// NotEqual assert test value to be not equal
+func NotEqual(t *testing.T, got, exp interface{}, args ...interface{}) {
+	notEqual(t, got, exp, 1, args...)
+}
+
+// Nil assert test value to be nil
+func Nil(t *testing.T, got interface{}, args ...interface{}) {
+	equal(t, got, nil, 1, args...)
+}
+
+// NotNil assert test value to be not nil
+func NotNil(t *testing.T, got interface{}, args ...interface{}) {
+	notEqual(t, got, nil, 1, args...)
+}
+
+// True assert test value to be true
+func True(t *testing.T, got interface{}, args ...interface{}) {
+	equal(t, got, true, 1, args...)
+}
+
+// False assert test value to be false
+func False(t *testing.T, got interface{}, args ...interface{}) {
+	notEqual(t, got, true, 1, args...)
+}
+
+// Zero assert test value to be zero value
+func Zero(t *testing.T, got interface{}, args ...interface{}) {
+	equal(t, IsZero(got), true, 1, args...)
+}
+
+// NotZero assert test value to be not zero value
+func NotZero(t *testing.T, got interface{}, args ...interface{}) {
+	notEqual(t, IsZero(got), true, 1, args...)
+}
+
+// Len assert length of test vaue to be exp
+func Len(t *testing.T, got interface{}, exp int, args ...interface{}) {
+	equal(t, Length(got), exp, 1, args...)
+}
+
+// NotLen assert length of test vaue to be not exp
+func NotLen(t *testing.T, got interface{}, exp int, args ...interface{}) {
+	notEqual(t, Length(got), exp, 1, args...)
+}
+
+// Contains assert test value to be contains
+func Contains(t *testing.T, got, exp interface{}, args ...interface{}) {
+	equal(t, IsContains(got, exp), true, 1, args...)
+}
+
+// NotContains assert test value to be contains
+func NotContains(t *testing.T, got, exp interface{}, args ...interface{}) {
+	notEqual(t, IsContains(got, exp), true, 1, args...)
+}
+
+// Match assert test value match exp pattern
+func Match(t *testing.T, got, exp interface{}, args ...interface{}) {
+	equal(t, IsMatch(got, exp), true, 1, args...)
+}
+
+// NotMatch assert test value not match exp pattern
+func NotMatch(t *testing.T, got, exp interface{}, args ...interface{}) {
+	notEqual(t, IsMatch(got, exp), true, 1, args...)
+}
+
+// Lt assert test value less than exp
+func Lt(t *testing.T, got, exp interface{}, args ...interface{}) {
+	equal(t, IsLt(got, exp), true, 1, args...)
+}
+
+// Le assert test value less than exp or equal
+func Le(t *testing.T, got, exp interface{}, args ...interface{}) {
+	equal(t, IsLe(got, exp), true, 1, args...)
+}
+
+// Gt assert test value greater than exp
+func Gt(t *testing.T, got, exp interface{}, args ...interface{}) {
+	equal(t, IsGt(got, exp), true, 1, args...)
+}
+
+// Ge assert test value greater than exp or equal
+func Ge(t *testing.T, got, exp interface{}, args ...interface{}) {
+	equal(t, IsGe(got, exp), true, 1, args...)
+}
+
+// Panic assert testing to be panic
+func Panic(t *testing.T, fn func(), args ...interface{}) {
+	defer func() {
+		ff := func() {
+			t.Error("! -", "assert expected to be panic")
+			if len(args) > 0 {
+				t.Error("! -", fmt.Sprint(args...))
+			}
+		}
+		ok := recover() != nil
+		assert(t, ok, ff, 2)
+	}()
+
+	fn()
+}
+
+// NotPanic assert testing to be panic
+func NotPanic(t *testing.T, fn func(), args ...interface{}) {
+	defer func() {
+		ff := func() {
+			t.Error("! -", "assert expected to be not panic")
+			if len(args) > 0 {
+				t.Error("! -", fmt.Sprint(args...))
+			}
+		}
+		ok := recover() == nil
+		assert(t, ok, ff, 3)
+	}()
+
+	fn()
+}
+
+func equal(t *testing.T, got, exp interface{}, step int, args ...interface{}) {
+	fn := func() {
+		switch got.(type) {
+		case error:
+			t.Errorf("! unexpected error: \"%s\"", got)
+		default:
+			t.Errorf("! expected %#v, but got %#v", exp, got)
+		}
+		if len(args) > 0 {
+			t.Error("! -", fmt.Sprint(args...))
+		}
+	}
+	ok := reflect.DeepEqual(exp, got)
+	assert(t, ok, fn, step+1)
+}
+
+func notEqual(t *testing.T, got, exp interface{}, step int, args ...interface{}) {
+	fn := func() {
+		t.Errorf("! unexpected: %#v", got)
+		if len(args) > 0 {
+			t.Error("! -", fmt.Sprint(args...))
+		}
+	}
+	ok := !reflect.DeepEqual(exp, got)
+	assert(t, ok, fn, step+1)
+}
+
+func assert(t *testing.T, pass bool, fn func(), step int) {
+	if !pass {
+		_, file, line, ok := runtime.Caller(step + 1)
+		if ok {
+			t.Errorf("%s:%d", file, line)
+		}
+		fn()
+		t.FailNow()
+	}
+}

vendor/github.com/likexian/gokit/assert/values.go

+/*
+ * Copyright 2012-2019 Li Kexian
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * A toolkit for Golang development
+ * https://www.likexian.com/
+ */
+
+package assert
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// ErrInvalid is value invalid for operation
+var ErrInvalid = errors.New("value if invalid")
+
+// ErrLess is expect to be greater error
+var ErrLess = errors.New("left is less the right")
+
+// ErrGreater is expect to be less error
+var ErrGreater = errors.New("left is greater then right")
+
+// CMP is compare operation
+var CMP = struct {
+	LT string
+	LE string
+	GT string
+	GE string
+}{
+	"<",
+	"<=",
+	">",
+	">=",
+}
+
+// IsZero returns value is zero value
+func IsZero(v interface{}) bool {
+	vv := reflect.ValueOf(v)
+	switch vv.Kind() {
+	case reflect.Invalid:
+		return true
+	case reflect.Bool:
+		return !vv.Bool()
+	case reflect.Ptr, reflect.Interface:
+		return vv.IsNil()
+	case reflect.Array, reflect.Slice, reflect.Map, reflect.String:
+		return vv.Len() == 0
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return vv.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return vv.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return vv.Float() == 0
+	default:
+		return false
+	}
+}
+
+// IsContains returns whether value is within array
+func IsContains(array interface{}, value interface{}) bool {
+	vv := reflect.ValueOf(array)
+	if vv.Kind() == reflect.Ptr || vv.Kind() == reflect.Interface {
+		if vv.IsNil() {
+			return false
+		}
+		vv = vv.Elem()
+	}
+
+	switch vv.Kind() {
+	case reflect.Invalid:
+		return false
+	case reflect.Slice:
+		for i := 0; i < vv.Len(); i++ {
+			if reflect.DeepEqual(value, vv.Index(i).Interface()) {
+				return true
+			}
+		}
+		return false
+	case reflect.Map:
+		s := vv.MapKeys()
+		for i := 0; i < len(s); i++ {
+			if reflect.DeepEqual(value, s[i].Interface()) {
+				return true
+			}
+		}
+		return false
+	case reflect.String:
+		ss := reflect.ValueOf(value)
+		switch ss.Kind() {
+		case reflect.String:
+			return strings.Contains(vv.String(), ss.String())
+		}
+		return false
+	default:
+		return reflect.DeepEqual(array, value)
+	}
+}
+
+// IsMatch returns if value v contains any match of pattern r
+//   IsMatch(regexp.MustCompile("v\d+"), "v100")
+//   IsMatch("v\d+", "v100")
+//   IsMatch("\d+\.\d+", 100.1)
+func IsMatch(r interface{}, v interface{}) bool {
+	var re *regexp.Regexp
+
+	if v, ok := r.(*regexp.Regexp); ok {
+		re = v
+	} else {
+		re = regexp.MustCompile(fmt.Sprint(r))
+	}
+
+	return re.MatchString(fmt.Sprint(v))
+}
+
+// Length returns length of value
+func Length(v interface{}) int {
+	vv := reflect.ValueOf(v)
+	if vv.Kind() == reflect.Ptr || vv.Kind() == reflect.Interface {
+		if vv.IsNil() {
+			return 0
+		}
+		vv = vv.Elem()
+	}
+
+	switch vv.Kind() {
+	case reflect.Invalid:
+		return 0
+	case reflect.Ptr, reflect.Interface:
+		return 0
+	case reflect.Array, reflect.Slice, reflect.Map, reflect.String:
+		return vv.Len()
+	default:
+		return len(fmt.Sprintf("%#v", v))
+	}
+}
+
+// IsLt returns if x less than y, value invalid will returns false
+func IsLt(x, y interface{}) bool {
+	return Compare(x, y, CMP.LT) == nil
+}
+
+// IsLe returns if x less than or equal to y, value invalid will returns false
+func IsLe(x, y interface{}) bool {
+	return Compare(x, y, CMP.LE) == nil
+}
+
+// IsGt returns if x greater than y, value invalid will returns false
+func IsGt(x, y interface{}) bool {
+	return Compare(x, y, CMP.GT) == nil
+}
+
+// IsGe returns if x greater than or equal to y, value invalid will returns false
+func IsGe(x, y interface{}) bool {
+	return Compare(x, y, CMP.GE) == nil
+}
+
+// Compare compare x and y, by operation
+// It returns nil for true, ErrInvalid for invalid operation, err for false
+//   Compare(1, 2, ">") // number compare -> true
+//   Compare("a", "a", ">=") // string compare -> true
+//   Compare([]string{"a", "b"}, []string{"a"}, "<") // slice len compare -> false
+func Compare(x, y interface{}, op string) error {
+	if !IsContains([]string{CMP.LT, CMP.LE, CMP.GT, CMP.GE}, op) {
+		return ErrInvalid
+	}
+
+	vv := reflect.ValueOf(x)
+	if vv.Kind() == reflect.Ptr || vv.Kind() == reflect.Interface {
+		if vv.IsNil() {
+			return ErrInvalid
+		}
+		vv = vv.Elem()
+	}
+
+	var c float64
+	switch vv.Kind() {
+	case reflect.Invalid:
+		return ErrInvalid
+	case reflect.String:
+		yy := reflect.ValueOf(y)
+		switch yy.Kind() {
+		case reflect.String:
+			c = float64(strings.Compare(vv.String(), yy.String()))
+		default:
+			return ErrInvalid
+		}
+	case reflect.Slice, reflect.Map, reflect.Array:
+		yy := reflect.ValueOf(y)
+		switch yy.Kind() {
+		case reflect.Slice, reflect.Map, reflect.Array:
+			c = float64(vv.Len() - yy.Len())
+		default:
+			return ErrInvalid
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		yy, err := ToInt64(y)
+		if err != nil {
+			return ErrInvalid
+		}
+		c = float64(vv.Int() - yy)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		yy, err := ToUint64(y)
+		if err != nil {
+			return ErrInvalid
+		}
+		c = float64(vv.Uint()) - float64(yy)
+	case reflect.Float32, reflect.Float64:
+		yy, err := ToFloat64(y)
+		if err != nil {
+			return ErrInvalid
+		}
+		c = float64(vv.Float() - yy)
+	default:
+		return ErrInvalid
+	}
+
+	switch {
+	case c < 0:
+		switch op {
+		case CMP.LT, CMP.LE:
+			return nil
+		default:
+			return ErrLess
+		}
+	case c > 0:
+		switch op {
+		case CMP.GT, CMP.GE:
+			return nil
+		default:
+			return ErrGreater
+		}
+	default:
+		switch op {
+		case CMP.LT:
+			return ErrGreater
+		case CMP.GT:
+			return ErrLess
+		default:
+			return nil
+		}
+	}
+}
+
+// ToInt64 returns int value for int or uint or float
+func ToInt64(v interface{}) (int64, error) {
+	vv := reflect.ValueOf(v)
+	switch vv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return int64(vv.Int()), nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return int64(vv.Uint()), nil
+	case reflect.Float32, reflect.Float64:
+		return int64(vv.Float()), nil
+	case reflect.String:
+		r, err := strconv.ParseInt(vv.String(), 10, 64)
+		if err != nil {
+			return 0, ErrInvalid
+		}
+		return r, nil
+	default:
+		return 0, ErrInvalid
+	}
+}
+
+// ToUint64 returns uint value for int or uint or float
+func ToUint64(v interface{}) (uint64, error) {
+	vv := reflect.ValueOf(v)
+	switch vv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return uint64(vv.Int()), nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return uint64(vv.Uint()), nil
+	case reflect.Float32, reflect.Float64:
+		return uint64(vv.Float()), nil
+	case reflect.String:
+		r, err := strconv.ParseUint(vv.String(), 10, 64)
+		if err != nil {
+			return 0, ErrInvalid
+		}
+		return r, nil
+	default:
+		return 0, ErrInvalid
+	}
+}
+
+// ToFloat64 returns float64 value for int or uint or float
+func ToFloat64(v interface{}) (float64, error) {
+	vv := reflect.ValueOf(v)
+	switch vv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return float64(vv.Int()), nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return float64(vv.Uint()), nil
+	case reflect.Float32, reflect.Float64:
+		return float64(vv.Float()), nil
+	case reflect.String:
+		r, err := strconv.ParseFloat(vv.String(), 64)
+		if err != nil {
+			return 0, ErrInvalid
+		}
+		return r, nil
+	default:
+		return 0, ErrInvalid
+	}
+}
+
+// If returns x if c is true, else y
+//   z = If(c, x, y)
+// equal to:
+//   z = c ? x : y
+func If(c bool, x, y interface{}) interface{} {
+	if c {
+		return x
+	}
+
+	return y
+}

vendor/github.com/mozillazg/go-httpheader/.bumpversion.cfg

+[bumpversion]
+commit = True
+tag = True
+current_version = 0.2.1
+
+[bumpversion:file:encode.go]
+

vendor/github.com/mozillazg/go-httpheader/.gitignore

+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
+dist/
+cover.html
+cover.out

vendor/github.com/mozillazg/go-httpheader/.travis.yml

+language: go
+go:
+  - 1.6
+  - 1.7
+  - 1.8
+  - tip
+
+sudo: false
+
+before_install:
+  - go get github.com/mattn/goveralls
+
+install:
+  - go get
+  - go build
+
+script:
+  - make test
+  - $HOME/gopath/bin/goveralls -service=travis-ci -ignore=vendor/
+
+matrix:
+  allow_failures:
+    - go: 1.6
+    - go: 1.7
+    - go: tip

vendor/github.com/mozillazg/go-httpheader/CHANGELOG.md

+# Changelog
+
+## 0.2.1 (2018-11-03)
+
+* add go.mod file to identify as a module
+
+
+## 0.2.0 (2017-06-24)
+
+* support http.Header field.
+
+
+## 0.1.0 (2017-06-10)
+
+* Initial Release

vendor/github.com/mozillazg/go-httpheader/LICENSE

+MIT License
+
+Copyright (c) 2017 mozillazg
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/github.com/mozillazg/go-httpheader/Makefile

+help:
+	@echo "test             run test"
+	@echo "lint             run lint"
+
+.PHONY: test
+test:
+	go test -v -cover -coverprofile cover.out
+	go tool cover -html=cover.out -o cover.html
+
+.PHONY: lint
+lint:
+	gofmt -s -w .
+	goimports -w .
+	golint .
+	go vet

vendor/github.com/mozillazg/go-httpheader/README.md

+# go-httpheader
+
+go-httpheader is a Go library for encoding structs into Header fields.
+
+[![Build Status](https://img.shields.io/travis/mozillazg/go-httpheader/master.svg)](https://travis-ci.org/mozillazg/go-httpheader)
+[![Coverage Status](https://img.shields.io/coveralls/mozillazg/go-httpheader/master.svg)](https://coveralls.io/r/mozillazg/go-httpheader?branch=master)
+[![Go Report Card](https://goreportcard.com/badge/github.com/mozillazg/go-httpheader)](https://goreportcard.com/report/github.com/mozillazg/go-httpheader)
+[![GoDoc](https://godoc.org/github.com/mozillazg/go-httpheader?status.svg)](https://godoc.org/github.com/mozillazg/go-httpheader)
+
+## install
+
+`go get -u github.com/mozillazg/go-httpheader`
+
+
+## usage
+
+```go
+package main
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/mozillazg/go-httpheader"
+)
+
+type Options struct {
+	hide         string
+	ContentType  string `header:"Content-Type"`
+	Length       int
+	XArray       []string `header:"X-Array"`
+	TestHide     string   `header:"-"`
+	IgnoreEmpty  string   `header:"X-Empty,omitempty"`
+	IgnoreEmptyN string   `header:"X-Empty-N,omitempty"`
+	CustomHeader http.Header
+}
+
+func main() {
+	opt := Options{
+		hide:         "hide",
+		ContentType:  "application/json",
+		Length:       2,
+		XArray:       []string{"test1", "test2"},
+		TestHide:     "hide",
+		IgnoreEmptyN: "n",
+		CustomHeader: http.Header{
+			"X-Test-1": []string{"233"},
+			"X-Test-2": []string{"666"},
+		},
+	}
+	h, _ := httpheader.Header(opt)
+	fmt.Printf("%#v", h)
+	// h:
+	// http.Header{
+	//	"X-Test-1":     []string{"233"},
+	//	"X-Test-2":     []string{"666"},
+	//	"Content-Type": []string{"application/json"},
+	//	"Length":       []string{"2"},
+	//	"X-Array":      []string{"test1", "test2"},
+	//	"X-Empty-N":    []string{"n"},
+	//}
+}
+```