WIP: add instrumentation to plugins

Signed-off-by: Laura Brehm <laurabrehm@hey.com>
docker · May 6, 2024 · d607756 · d607756
1 parent e81b835
commit d607756
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Showing 3 changed files with 32 additions and 6 deletions.
diff --git a/cli-plugins/plugin/plugin.go b/cli-plugins/plugin/plugin.go
@@ -46,6 +46,22 @@ 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
+				//nolint:unparam // necessary because error will always be nil here
+				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(ctx, cmd)
+				err := ogRunE(cmd, args)
+				stopInstrumentation(err)
+				return err
+			}
 		})
 		return err
 	}

diff --git a/cli/command/telemetry_utils.go b/cli/command/telemetry_utils.go
@@ -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 {
@@ -55,17 +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(ctx, cmd)
 			cmdErr := ogRunE(cmd, args)
-			stopCobraCmdTimer(cmdErr)
+			stopInstrumentation(cmdErr)
 			return cmdErr
 		}
 
 		return ogPersistentPreRunE(cmd, args)
 	}
 }
 
+// StartInstrumentation instruments CLI commands with the individual metrics and spans configured.
+// It's the main command OTel utlility, 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(ctx context.Context, cmd *cobra.Command) (stopInstrumentation func(error)) {
+	mp := cli.MeterProvider(ctx)
+	meter := getDefaultMeter(mp)
+	baseAttrs := BaseCommandAttributes(cmd, cli)
+	return startCobraCommandTimer(cmd, meter, baseAttrs)
+}
+
 func startCobraCommandTimer(cmd *cobra.Command, meter metric.Meter, attrs []attribute.KeyValue) func(err error) {
 	ctx := cmd.Context()
 	durationCounter, _ := meter.Float64Counter(

diff --git a/cmd/docker/docker.go b/cmd/docker/docker.go
@@ -310,8 +310,9 @@ func runDocker(ctx context.Context, dockerCli *command.DockerCli) error {
 
 	mp := dockerCli.MeterProvider(ctx)
 	defer mp.Shutdown(ctx)
+
 	otel.SetMeterProvider(mp)
-	dockerCli.InstrumentCobraCommands(cmd, mp)
+	dockerCli.InstrumentCobraCommands(ctx, cmd)
 
 	var envs []string
 	args, os.Args, envs, err = processAliases(dockerCli, cmd, args, os.Args)