152 lines
3.4 KiB
Go
152 lines
3.4 KiB
Go
package exec
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import (
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"bytes"
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"fmt"
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"io"
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"log"
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"os/exec"
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"time"
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"github.com/influxdata/telegraf"
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"github.com/influxdata/telegraf/internal"
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"github.com/influxdata/telegraf/plugins/outputs"
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"github.com/influxdata/telegraf/plugins/serializers"
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)
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const maxStderrBytes = 512
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// Exec defines the exec output plugin.
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type Exec struct {
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Command []string `toml:"command"`
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Timeout internal.Duration `toml:"timeout"`
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runner Runner
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serializer serializers.Serializer
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}
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var sampleConfig = `
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## Command to ingest metrics via stdin.
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command = ["tee", "-a", "/dev/null"]
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## Timeout for command to complete.
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# timeout = "5s"
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## Data format to output.
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## Each data format has its own unique set of configuration options, read
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## more about them here:
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## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_OUTPUT.md
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# data_format = "influx"
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`
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// SetSerializer sets the serializer for the output.
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func (e *Exec) SetSerializer(serializer serializers.Serializer) {
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e.serializer = serializer
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}
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// Connect satisfies the Output interface.
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func (e *Exec) Connect() error {
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return nil
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}
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// Close satisfies the Output interface.
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func (e *Exec) Close() error {
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return nil
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}
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// Description describes the plugin.
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func (e *Exec) Description() string {
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return "Send metrics to command as input over stdin"
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}
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// SampleConfig returns a sample configuration.
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func (e *Exec) SampleConfig() string {
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return sampleConfig
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}
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// Write writes the metrics to the configured command.
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func (e *Exec) Write(metrics []telegraf.Metric) error {
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var buffer bytes.Buffer
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serializedMetrics, err := e.serializer.SerializeBatch(metrics)
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if err != nil {
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return err
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}
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buffer.Write(serializedMetrics)
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if buffer.Len() <= 0 {
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return nil
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}
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return e.runner.Run(e.Timeout.Duration, e.Command, &buffer)
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}
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// Runner provides an interface for running exec.Cmd.
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type Runner interface {
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Run(time.Duration, []string, io.Reader) error
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}
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// CommandRunner runs a command with the ability to kill the process before the timeout.
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type CommandRunner struct {
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cmd *exec.Cmd
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}
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// Run runs the command.
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func (c *CommandRunner) Run(timeout time.Duration, command []string, buffer io.Reader) error {
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cmd := exec.Command(command[0], command[1:]...)
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cmd.Stdin = buffer
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var stderr bytes.Buffer
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cmd.Stderr = &stderr
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err := internal.RunTimeout(cmd, timeout)
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s := stderr
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if err != nil {
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if err == internal.TimeoutErr {
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return fmt.Errorf("%q timed out and was killed", command)
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}
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if s.Len() > 0 {
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log.Printf("E! [outputs.exec] Command error: %q", truncate(s))
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}
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if status, ok := internal.ExitStatus(err); ok {
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return fmt.Errorf("%q exited %d with %s", command, status, err.Error())
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}
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return fmt.Errorf("%q failed with %s", command, err.Error())
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}
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c.cmd = cmd
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return nil
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}
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func truncate(buf bytes.Buffer) string {
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// Limit the number of bytes.
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didTruncate := false
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if buf.Len() > maxStderrBytes {
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buf.Truncate(maxStderrBytes)
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didTruncate = true
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}
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if i := bytes.IndexByte(buf.Bytes(), '\n'); i > 0 {
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// Only show truncation if the newline wasn't the last character.
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if i < buf.Len()-1 {
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didTruncate = true
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}
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buf.Truncate(i)
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}
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if didTruncate {
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buf.WriteString("...")
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}
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return buf.String()
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}
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func init() {
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outputs.Add("exec", func() telegraf.Output {
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return &Exec{
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runner: &CommandRunner{},
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Timeout: internal.Duration{Duration: time.Second * 5},
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}
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})
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}
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