consul: truncate output strings to 200 characters

client/allocrunner/taskrunner/script_check_hook.go

@@ -3,6 +3,7 @@ package taskrunner
 import (
 	"context"
 	"fmt"
+	"strings"
 	"sync"
 	"time"
 
@@ -14,6 +15,7 @@ import (
 	"github.com/hashicorp/nomad/client/consul"
 	"github.com/hashicorp/nomad/client/taskenv"
 	agentconsul "github.com/hashicorp/nomad/command/agent/consul"
+	"github.com/hashicorp/nomad/helper"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
@@ -21,8 +23,14 @@ var _ interfaces.TaskPoststartHook = &scriptCheckHook{}
 var _ interfaces.TaskUpdateHook = &scriptCheckHook{}
 var _ interfaces.TaskStopHook = &scriptCheckHook{}
 
-// default max amount of time to wait for all scripts on shutdown.
-const defaultShutdownWait = time.Minute
+const (
+	// default max amount of time to wait for all scripts on shutdown.
+	defaultShutdownWait = time.Minute
+
+	// maxOutputMsgSize is the max length of script check output that will
+	// be logged
+	maxOutputMsgSize = 200
+)
 
 type scriptCheckHookConfig struct {
 	alloc        *structs.Allocation
@@ -372,7 +380,8 @@ func newScriptCheckCallback(s *scriptCheck) taskletCallback {
 
 		// If the check is unhealthy, log the output
 		if state == api.HealthCritical || state == api.HealthWarning {
-			s.logger.Warn("unhealthy script check", "health", state, "output", hclog.Quote(outputMsg))
+			trimmed := helper.TruncateString(strings.TrimSpace(outputMsg), maxOutputMsgSize)
+			s.logger.Warn("unhealthy script check", "health", state, "output", hclog.Quote(trimmed))
 		}
 
 		// heartbeat the check to Consul

helper/funcs.go

@@ -551,3 +551,14 @@ func PathEscapesSandbox(sandboxDir, path string) bool {
 	}
 	return false
 }
+
+// TruncateString ensures a string is below max characters. If not the string
+// is truncated to "max-3" and "..." are appended.
+//
+// Max must be > 3
+func TruncateString(s string, max int) string {
+	if len(s) > max {
+		return s[:max-3] + "..."
+	}
+	return s
+}

helper/funcs_test.go

@@ -8,6 +8,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -403,3 +404,54 @@ func TestPathEscapesSandbox(t *testing.T) {
 		})
 	}
 }
+
+func TestTruncateString(t *testing.T) {
+	cases := []struct {
+		In  string
+		Max int
+		Out string
+	}{
+		{
+			In:  "Hello World!",
+			Max: 3,
+			Out: "...",
+		},
+		{
+			In:  "Hello World!",
+			Max: 4,
+			Out: "H...",
+		},
+		{
+			In:  "Hello World!",
+			Max: 5,
+			Out: "He...",
+		},
+		{
+			In:  "Hello World!",
+			Max: 11,
+			Out: "Hello Wo...",
+		},
+		{
+			In:  "Hello World!",
+			Max: 12,
+			Out: "Hello World!",
+		},
+		{
+			In:  "Hello World!",
+			Max: 13,
+			Out: "Hello World!",
+		},
+		{
+			In:  "",
+			Max: 3,
+			Out: "",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(fmt.Sprintf("%s-%d-%s", tc.In, tc.Max, tc.Out), func(t *testing.T) {
+			out := TruncateString(tc.In, tc.Max)
+			assert.Equal(t, tc.Out, out)
+		})
+	}
+}