exec plugins should not truncate messages in debug mode (#8333)

cmd/telegraf/telegraf.go

@@ -15,6 +15,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/agent"
 	"github.com/influxdata/telegraf/config"
 	"github.com/influxdata/telegraf/internal"
@@ -158,8 +159,9 @@ func runAgent(ctx context.Context,
 	}
 
 	// Setup logging as configured.
+	telegraf.Debug = ag.Config.Agent.Debug || *fDebug
 	logConfig := logger.LogConfig{
-		Debug:               ag.Config.Agent.Debug || *fDebug,
+		Debug:               telegraf.Debug,
 		Quiet:               ag.Config.Agent.Quiet || *fQuiet,
 		LogTarget:           ag.Config.Agent.LogTarget,
 		Logfile:             ag.Config.Agent.Logfile,

plugin.go

@@ -1,5 +1,7 @@
 package telegraf
 
+var Debug bool
+
 // Initializer is an interface that all plugin types: Inputs, Outputs,
 // Processors, and Aggregators can optionally implement to initialize the
 // plugin.
@@ -21,7 +23,7 @@ type PluginDescriber interface {
 	Description() string
 }
 
-// Logger defines an interface for logging.
+// Logger defines an plugin-related interface for logging.
 type Logger interface {
 	// Errorf logs an error message, patterned after log.Printf.
 	Errorf(format string, args ...interface{})

plugins/inputs/exec/exec.go

@@ -3,6 +3,7 @@ package exec
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"os/exec"
 	"path/filepath"
 	"runtime"
@@ -39,12 +40,12 @@ const sampleConfig = `
   data_format = "influx"
 `
 
-const MaxStderrBytes = 512
+const MaxStderrBytes int = 512
 
 type Exec struct {
-	Commands []string
-	Command  string
-	Timeout  internal.Duration
+	Commands []string          `toml:"commands"`
+	Command  string            `toml:"command"`
+	Timeout  internal.Duration `toml:"timeout"`
 
 	parser parsers.Parser
 
@@ -85,16 +86,16 @@ func (c CommandRunner) Run(
 
 	runErr := internal.RunTimeout(cmd, timeout)
 
-	out = removeCarriageReturns(out)
-	if stderr.Len() > 0 {
-		stderr = removeCarriageReturns(stderr)
-		stderr = truncate(stderr)
+	out = removeWindowsCarriageReturns(out)
+	if stderr.Len() > 0 && !telegraf.Debug {
+		stderr = removeWindowsCarriageReturns(stderr)
+		stderr = c.truncate(stderr)
 	}
 
 	return out.Bytes(), stderr.Bytes(), runErr
 }
 
-func truncate(buf bytes.Buffer) bytes.Buffer {
+func (c CommandRunner) truncate(buf bytes.Buffer) bytes.Buffer {
 	// Limit the number of bytes.
 	didTruncate := false
 	if buf.Len() > MaxStderrBytes {
@@ -114,27 +115,21 @@ func truncate(buf bytes.Buffer) bytes.Buffer {
 	return buf
 }
 
-// removeCarriageReturns removes all carriage returns from the input if the
+// removeWindowsCarriageReturns removes all carriage returns from the input if the
 // OS is Windows. It does not return any errors.
-func removeCarriageReturns(b bytes.Buffer) bytes.Buffer {
+func removeWindowsCarriageReturns(b bytes.Buffer) bytes.Buffer {
 	if runtime.GOOS == "windows" {
 		var buf bytes.Buffer
 		for {
-			byt, er := b.ReadBytes(0x0D)
-			end := len(byt)
-			if nil == er {
-				end--
+			byt, err := b.ReadBytes(0x0D)
+			byt = bytes.TrimRight(byt, "\x0d")
+			if len(byt) > 0 {
+				_, _ = buf.Write(byt)
 			}
-			if nil != byt {
-				buf.Write(byt[:end])
-			} else {
-				break
-			}
-			if nil != er {
-				break
+			if err == io.EOF {
+				return buf
 			}
 		}
-		b = buf
 	}
 	return b
 }

plugins/inputs/exec/exec_test.go

@@ -259,9 +259,10 @@ func TestTruncate(t *testing.T) {
 		},
 	}
 
+	c := CommandRunner{}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			res := truncate(*tt.bufF())
+			res := c.truncate(*tt.bufF())
 			require.Equal(t, tt.expF().Bytes(), res.Bytes())
 		})
 	}
@@ -272,14 +273,14 @@ func TestRemoveCarriageReturns(t *testing.T) {
 		// Test that all carriage returns are removed
 		for _, test := range crTests {
 			b := bytes.NewBuffer(test.input)
-			out := removeCarriageReturns(*b)
+			out := removeWindowsCarriageReturns(*b)
 			assert.True(t, bytes.Equal(test.output, out.Bytes()))
 		}
 	} else {
 		// Test that the buffer is returned unaltered
 		for _, test := range crTests {
 			b := bytes.NewBuffer(test.input)
-			out := removeCarriageReturns(*b)
+			out := removeWindowsCarriageReturns(*b)
 			assert.True(t, bytes.Equal(test.input, out.Bytes()))
 		}
 	}

plugins/outputs/exec/README.md

@@ -8,6 +8,8 @@ The command should be defined similar to docker's `exec` form:
 
 On non-zero exit stderr will be logged at error level.
 
+For better performance, consider execd, which runs continuously.
+
 ### Configuration
 
 ```toml

plugins/outputs/exec/exec.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"log"
 	"os/exec"
+	"runtime"
 	"time"
 
 	"github.com/influxdata/telegraf"
@@ -39,6 +40,10 @@ var sampleConfig = `
   # data_format = "influx"
 `
 
+func (e *Exec) Init() error {
+	return nil
+}
+
 // SetSerializer sets the serializer for the output.
 func (e *Exec) SetSerializer(serializer serializers.Serializer) {
 	e.serializer = serializer
@@ -105,8 +110,13 @@ func (c *CommandRunner) Run(timeout time.Duration, command []string, buffer io.R
 			return fmt.Errorf("%q timed out and was killed", command)
 		}
 
+		s = removeWindowsCarriageReturns(s)
 		if s.Len() > 0 {
-			log.Printf("E! [outputs.exec] Command error: %q", truncate(s))
+			if !telegraf.Debug {
+				log.Printf("E! [outputs.exec] Command error: %q", c.truncate(s))
+			} else {
+				log.Printf("D! [outputs.exec] Command error: %q", s)
+			}
 		}
 
 		if status, ok := internal.ExitStatus(err); ok {
@@ -121,7 +131,7 @@ func (c *CommandRunner) Run(timeout time.Duration, command []string, buffer io.R
 	return nil
 }
 
-func truncate(buf bytes.Buffer) string {
+func (c *CommandRunner) truncate(buf bytes.Buffer) string {
 	// Limit the number of bytes.
 	didTruncate := false
 	if buf.Len() > maxStderrBytes {
@@ -149,3 +159,22 @@ func init() {
 		}
 	})
 }
+
+// removeWindowsCarriageReturns removes all carriage returns from the input if the
+// OS is Windows. It does not return any errors.
+func removeWindowsCarriageReturns(b bytes.Buffer) bytes.Buffer {
+	if runtime.GOOS == "windows" {
+		var buf bytes.Buffer
+		for {
+			byt, err := b.ReadBytes(0x0D)
+			byt = bytes.TrimRight(byt, "\x0d")
+			if len(byt) > 0 {
+				_, _ = buf.Write(byt)
+			}
+			if err == io.EOF {
+				return buf
+			}
+		}
+	}
+	return b
+}

plugins/outputs/exec/exec_test.go

@@ -83,9 +83,10 @@ func TestTruncate(t *testing.T) {
 			len:  len("hola") + len("..."),
 		},
 	}
+	c := CommandRunner{}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			s := truncate(*tt.buf)
+			s := c.truncate(*tt.buf)
 			require.Equal(t, tt.len, len(s))
 		})
 	}