[cmd/builder] Add --verbose flag to log go subcommands output (#8715)

**Description:** 

Log output from `go` subcommands being ran as part of an ocb build if passing the `--verbose` flag

.chloggen/mx-psi_logging-builder.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: cmd/builder
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Add --verbose flag to log `go` subcommands output that are ran as part of a build"
+
+# One or more tracking issues or pull requests related to the change
+issues: [8715]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

cmd/builder/internal/builder/config.go

@@ -28,6 +28,7 @@ type Config struct {
 	SkipCompilation bool   `mapstructure:"-"`
 	SkipGetModules  bool   `mapstructure:"-"`
 	LDFlags         string `mapstructure:"-"`
+	Verbose         bool   `mapstructure:"-"`
 
 	Distribution Distribution `mapstructure:"dist"`
 	Exporters    []Module     `mapstructure:"exporters"`

cmd/builder/internal/builder/main.go

@@ -13,13 +13,35 @@ import (
 	"time"
 
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapio"
 )
 
 var (
 	// ErrGoNotFound is returned when a Go binary hasn't been found
 	ErrGoNotFound = errors.New("go binary not found")
 )
 
+func runGoCommand(cfg Config, args ...string) error {
+	cfg.Logger.Info("Running go subcommand.", zap.Any("arguments", args))
+	// #nosec G204 -- cfg.Distribution.Go is trusted to be a safe path and the caller is assumed to have carried out necessary input validation
+	cmd := exec.Command(cfg.Distribution.Go, args...)
+	cmd.Dir = cfg.Distribution.OutputPath
+
+	if cfg.Verbose {
+		writer := &zapio.Writer{Log: cfg.Logger}
+		defer func() { _ = writer.Close() }()
+		cmd.Stdout = writer
+		cmd.Stderr = writer
+		return cmd.Run()
+	}
+
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("go subcommand failed with args '%v': %w. Output:\n%s", args, err, out)
+	}
+
+	return nil
+}
+
 // GenerateAndCompile will generate the source files based on the given configuration, update go mod, and will compile into a binary
 func GenerateAndCompile(cfg Config) error {
 	if err := Generate(cfg); err != nil {
@@ -93,11 +115,8 @@ func Compile(cfg Config) error {
 	if cfg.Distribution.BuildTags != "" {
 		args = append(args, "-tags", cfg.Distribution.BuildTags)
 	}
-	// #nosec G204 -- cfg.Distribution.Go is trusted to be a safe path and the caller is  assumed to have carried out necessary input validation
-	cmd := exec.Command(cfg.Distribution.Go, args...)
-	cmd.Dir = cfg.Distribution.OutputPath
-	if out, err := cmd.CombinedOutput(); err != nil {
-		return fmt.Errorf("failed to compile the OpenTelemetry Collector distribution: %w. Output:\n%s", err, out)
+	if err := runGoCommand(cfg, args...); err != nil {
+		return fmt.Errorf("failed to compile the OpenTelemetry Collector distribution: %w", err)
 	}
 	cfg.Logger.Info("Compiled", zap.String("binary", fmt.Sprintf("%s/%s", cfg.Distribution.OutputPath, cfg.Distribution.Name)))
 
@@ -112,18 +131,12 @@ func GetModules(cfg Config) error {
 	}
 
 	// ambiguous import: found package cloud.google.com/go/compute/metadata in multiple modules
-	// #nosec G204 -- cfg.Distribution.Go is trusted to be a safe path
-	cmd := exec.Command(cfg.Distribution.Go, "get", "cloud.google.com/go")
-	cmd.Dir = cfg.Distribution.OutputPath
-	if out, err := cmd.CombinedOutput(); err != nil {
-		return fmt.Errorf("failed to go get: %w. Output:\n%s", err, out)
+	if err := runGoCommand(cfg, "get", "cloud.google.com/go"); err != nil {
+		return fmt.Errorf("failed to go get: %w", err)
 	}
 
-	// #nosec G204 -- cfg.Distribution.Go is trusted to be a safe path
-	cmd = exec.Command(cfg.Distribution.Go, "mod", "tidy", "-compat=1.20")
-	cmd.Dir = cfg.Distribution.OutputPath
-	if out, err := cmd.CombinedOutput(); err != nil {
-		return fmt.Errorf("failed to update go.mod: %w. Output:\n%s", err, out)
+	if err := runGoCommand(cfg, "mod", "tidy", "-compat=1.20"); err != nil {
+		return fmt.Errorf("failed to update go.mod: %w", err)
 	}
 
 	cfg.Logger.Info("Getting go modules")
@@ -132,11 +145,8 @@ func GetModules(cfg Config) error {
 	retries := 3
 	failReason := "unknown"
 	for i := 1; i <= retries; i++ {
-		// #nosec G204
-		cmd := exec.Command(cfg.Distribution.Go, "mod", "download")
-		cmd.Dir = cfg.Distribution.OutputPath
-		if out, err := cmd.CombinedOutput(); err != nil {
-			failReason = fmt.Sprintf("%s. Output:\n%s", err, out)
+		if err := runGoCommand(cfg, "mod", "download"); err != nil {
+			failReason = err.Error()
 			cfg.Logger.Info("Failed modules download", zap.String("retry", fmt.Sprintf("%d/%d", i, retries)))
 			time.Sleep(5 * time.Second)
 			continue

cmd/builder/internal/command.go

@@ -31,6 +31,7 @@ const (
 	distributionOutputPathFlag     = "output-path"
 	distributionGoFlag             = "go"
 	distributionModuleFlag         = "module"
+	verboseFlag                    = "verbose"
 )
 
 var (
@@ -82,6 +83,7 @@ configuration is provided, ocb will generate a default Collector.
 	cmd.Flags().BoolVar(&cfg.SkipGenerate, skipGenerateFlag, false, "Whether builder should skip generating go code (default false)")
 	cmd.Flags().BoolVar(&cfg.SkipCompilation, skipCompilationFlag, false, "Whether builder should only generate go code with no compile of the collector (default false)")
 	cmd.Flags().BoolVar(&cfg.SkipGetModules, skipGetModulesFlag, false, "Whether builder should skip updating go.mod and retrieve Go module list (default false)")
+	cmd.Flags().BoolVar(&cfg.Verbose, verboseFlag, false, "Whether builder should print verbose output (default false)")
 	cmd.Flags().StringVar(&cfg.LDFlags, ldflagsFlag, "", `ldflags to include in the "go build" command`)
 	cmd.Flags().StringVar(&cfg.Distribution.Name, distributionNameFlag, "otelcol-custom", "The executable name for the OpenTelemetry Collector distribution")
 	if err := cmd.Flags().MarkDeprecated(distributionNameFlag, "use config distribution::name"); err != nil {