logger: add command logging

Add a 'LogCommand()' function to the 'TraceLogger', called in
'argparser.InvokeSubcommand()' right before the command is invoked. To
remain consistent with Git, do this only when a toplevel command (indicated
by 'isTopLevel') is invoked; nothing is done for subcommands of those
commands.

In the trace2 logger, this corresponds to the "cmd_name" event.

Signed-off-by: Victoria Dye <[email protected]>

Author: vdye

internal/argparse/argparse.go

@@ -215,6 +215,10 @@ func (a *argParser) InvokeSubcommand(ctx context.Context) error {
 		panic("subcommand has not been parsed")
 	}
 
+	if a.isTopLevel {
+		a.logger.LogCommand(ctx, a.selectedSubcommand.Name())
+	}
+
 	return a.selectedSubcommand.Run(ctx, a.Args())
 }
 

internal/log/logger.go

@@ -9,6 +9,7 @@ import (
 type loggedError error
 
 type TraceLogger interface {
+	LogCommand(ctx context.Context, commandName string) context.Context
 	Error(ctx context.Context, err error) error
 	Errorf(ctx context.Context, format string, a ...any) error
 	Exit(ctx context.Context, exitCode int)

internal/log/trace2.go

@@ -166,6 +166,14 @@ func (t *Trace2) logExit(ctx context.Context, exitCode int) {
 	t.logger.Sync()
 }
 
+func (t *Trace2) LogCommand(ctx context.Context, commandName string) context.Context {
+	ctx, sharedFields := t.sharedFields(ctx)
+
+	t.logger.Info("cmd_name", sharedFields.with(zap.String("name", commandName))...)
+
+	return ctx
+}
+
 func (t *Trace2) Error(ctx context.Context, err error) error {
 	// We only want to log the error if it's not already logged deeper in the
 	// call stack.