Add flag to append a comment to a profile. (#221)

Add a flag to append a comment to a profile.

internal/driver/cli.go

 	Timeout      int
 	Symbolize    string
 	HTTPHostport string
+	Comment      string
 }
 
 // Parse parses the command lines through the specified flags package
 	flag := o.Flagset
 	// Comparisons.
 	flagBase := flag.StringList("base", "", "Source for base profile for comparison")
-	// Internal options.
+	// Source options.
 	flagSymbolize := flag.String("symbolize", "", "Options for profile symbolization")
 	flagBuildID := flag.String("buildid", "", "Override build id for first mapping")
+	flagTimeout := flag.Int("timeout", -1, "Timeout in seconds for fetching a profile")
+	flagAddComment := flag.String("add_comment", "", "Annotation string to record in the profile")
 	// CPU profile options
 	flagSeconds := flag.Int("seconds", -1, "Length of time for dynamic profiles")
 	// Heap profile options
 	flagMeanDelay := flag.Bool("mean_delay", false, "Display mean delay at each region")
 	flagTools := flag.String("tools", os.Getenv("PPROF_TOOLS"), "Path for object tool pathnames")
 
-	flagTimeout := flag.Int("timeout", -1, "Timeout in seconds for fetching a profile")
 	flagHTTP := flag.String("http", "", "Present interactive web based UI at the specified http host:port")
 
 	// Flags used during command processing
 		Timeout:      *flagTimeout,
 		Symbolize:    *flagSymbolize,
 		HTTPHostport: *flagHTTP,
+		Comment:      *flagAddComment,
 	}
 
 	for _, s := range *flagBase {
 	"    -seconds              Duration for time-based profile collection\n" +
 	"    -timeout              Timeout in seconds for profile collection\n" +
 	"    -buildid              Override build id for main binary\n" +
+	"    -add_comment          Free-form annotation to add to the profile\n" +
+	"                          Displayed on some reports or with pprof -comments\n" +
 	"    -base source          Source of profile to use as baseline\n" +
 	"    profile.pb.gz         Profile in compressed protobuf format\n" +
 	"    legacy_profile        Profile in legacy pprof format\n" +

internal/driver/driver_test.go

 		{"dot,unit=minimum", "heap_sizetags"},
 		{"dot,addresses,flat,ignore=[X3]002,focus=[X1]000", "contention"},
 		{"dot,files,cum", "contention"},
-		{"comments", "cpu"},
+		{"comments,add_comment=some-comment", "cpu"},
 		{"comments", "heap"},
 		{"tags", "cpu"},
 		{"tags,tagignore=tag[13],tagfocus=key[12]", "cpu"},
 			addFlags(&f, flags[:1])
 			solution = solutionFilename(tc.source, &f)
 		}
+		// The add_comment flag is not idempotent so only apply it on the first run.
+		delete(f.strings, "add_comment")
 
 		// Second pprof invocation to read the profile from profile.proto
 		// and generate a report.
 		}
 	case "heap_tags":
 		p = heapProfile()
-
 		for i := 0; i < len(p.Sample); i += 2 {
 			s := p.Sample[i]
 			if s.Label == nil {
 			s.NumLabel["request"] = s.NumLabel["bytes"]
 			s.Label["key1"] = []string{"tag"}
 		}
-
 	case "contention":
 		p = contentionProfile()
 	case "symbolz":

internal/driver/fetch.go

 	p.RemoveUninteresting()
 	unsourceMappings(p)
 
+	if s.Comment != "" {
+		p.Comments = append(p.Comments, s.Comment)
+	}
+
 	// Save a copy of the merged profile if there is at least one remote source.
 	if save {
 		dir, err := setTmpDir(o.UI)

internal/driver/testdata/pprof.cpu.comments

+some-comment