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OTel: add command.time metric to plugin commands
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Signed-off-by: Laura Brehm <laurabrehm@hey.com>
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laurazard committed May 14, 2024
1 parent 02537ea commit f07834d
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Showing 3 changed files with 41 additions and 8 deletions.
18 changes: 18 additions & 0 deletions cli-plugins/plugin/plugin.go
Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,24 @@ func RunPlugin(dockerCli *command.DockerCli, plugin *cobra.Command, meta manager
opts = append(opts, withPluginClientConn(plugin.Name()))
}
err = tcmd.Initialize(opts...)
ogRunE := cmd.RunE
if ogRunE == nil {
ogRun := cmd.Run
// necessary because error will always be nil here
// see: https://github.com/golangci/golangci-lint/issues/1379
//nolint:unparam
ogRunE = func(cmd *cobra.Command, args []string) error {
ogRun(cmd, args)
return nil
}
cmd.Run = nil
}
cmd.RunE = func(cmd *cobra.Command, args []string) error {
stopInstrumentation := dockerCli.StartInstrumentation(cmd)
err := ogRunE(cmd, args)
stopInstrumentation(err)
return err
}
})
return err
}
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29 changes: 22 additions & 7 deletions cli/command/telemetry_utils.go
Original file line number Diff line number Diff line change
Expand Up @@ -26,8 +26,7 @@ func BaseCommandAttributes(cmd *cobra.Command, streams Streams) []attribute.KeyV
// Note: this should be the last func to wrap/modify the PersistentRunE/RunE funcs before command execution.
//
// can also be used for spans!
func (cli *DockerCli) InstrumentCobraCommands(cmd *cobra.Command, mp metric.MeterProvider) {
meter := getDefaultMeter(mp)
func (cli *DockerCli) InstrumentCobraCommands(ctx context.Context, cmd *cobra.Command) {
// If PersistentPreRunE is nil, make it execute PersistentPreRun and return nil by default
ogPersistentPreRunE := cmd.PersistentPreRunE
if ogPersistentPreRunE == nil {
Expand Down Expand Up @@ -55,19 +54,27 @@ func (cli *DockerCli) InstrumentCobraCommands(cmd *cobra.Command, mp metric.Mete
}
cmd.RunE = func(cmd *cobra.Command, args []string) error {
// start the timer as the first step of every cobra command
baseAttrs := BaseCommandAttributes(cmd, cli)
stopCobraCmdTimer := startCobraCommandTimer(cmd, meter, baseAttrs)
stopInstrumentation := cli.StartInstrumentation(cmd)
cmdErr := ogRunE(cmd, args)
stopCobraCmdTimer(cmdErr)
stopInstrumentation(cmdErr)
return cmdErr
}

return ogPersistentPreRunE(cmd, args)
}
}

func startCobraCommandTimer(cmd *cobra.Command, meter metric.Meter, attrs []attribute.KeyValue) func(err error) {
ctx := cmd.Context()
// StartInstrumentation instruments CLI commands with the individual metrics and spans configured.
// It's the main command OTel utility, and new command-related metrics should be added to it.
// It should be called immediately before command execution, and returns a stopInstrumentation function
// that must be called with the error resulting from the command execution.
func (cli *DockerCli) StartInstrumentation(cmd *cobra.Command) (stopInstrumentation func(error)) {
baseAttrs := BaseCommandAttributes(cmd, cli)
return startCobraCommandTimer(cli.MeterProvider(), baseAttrs)
}

func startCobraCommandTimer(mp metric.MeterProvider, attrs []attribute.KeyValue) func(err error) {
meter := getDefaultMeter(mp)
durationCounter, _ := meter.Float64Counter(
"command.time",
metric.WithDescription("Measures the duration of the cobra command"),
Expand All @@ -76,12 +83,20 @@ func startCobraCommandTimer(cmd *cobra.Command, meter metric.Meter, attrs []attr
start := time.Now()

return func(err error) {
// Use a new context for the export so that the command being cancelled
// doesn't affect the metrics, and we get metrics for cancelled commands.
ctx, cancel := context.WithTimeout(context.Background(), exportTimeout)
defer cancel()

duration := float64(time.Since(start)) / float64(time.Millisecond)
cmdStatusAttrs := attributesFromError(err)
durationCounter.Add(ctx, duration,
metric.WithAttributes(attrs...),
metric.WithAttributes(cmdStatusAttrs...),
)
if mp, ok := mp.(MeterProvider); ok {
mp.ForceFlush(ctx)
}
}
}

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2 changes: 1 addition & 1 deletion cmd/docker/docker.go
Original file line number Diff line number Diff line change
Expand Up @@ -315,7 +315,7 @@ func runDocker(ctx context.Context, dockerCli *command.DockerCli) error {
fmt.Fprint(dockerCli.Err(), "Warning: Unexpected OTEL error, metrics may not be flushed")
}

dockerCli.InstrumentCobraCommands(cmd, mp)
dockerCli.InstrumentCobraCommands(ctx, cmd)

var envs []string
args, os.Args, envs, err = processAliases(dockerCli, cmd, args, os.Args)
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