gobuilder: write build and benchmarking logs to disk

R=rsc
CC=golang-dev
https://golang.org/cl/2637041

misc/dashboard/builder/exec.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"exec"
+	"io"
 	"os"
 	"strings"
 )
@@ -21,8 +22,9 @@ func run(envv []string, dir string, argv ...string) os.Error {
 	return p.Close()
 }
 
-// runLog runs a process and returns the combined stdout/stderr
-func runLog(envv []string, dir string, argv ...string) (output string, exitStatus int, err os.Error) {
+// runLog runs a process and returns the combined stdout/stderr, 
+// as well as writing it to logfile (if specified).
+func runLog(envv []string, logfile, dir string, argv ...string) (output string, exitStatus int, err os.Error) {
 	bin, err := pathLookup(argv[0])
 	if err != nil {
 		return
@@ -34,15 +36,24 @@ func runLog(envv []string, dir string, argv ...string) (output string, exitStatu
 	}
 	defer p.Close()
 	b := new(bytes.Buffer)
-	_, err = b.ReadFrom(p.Stdout)
+	var w io.Writer = b
+	if logfile != "" {
+		f, err := os.Open(logfile, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
+		if err != nil {
+			return
+		}
+		defer f.Close()
+		w = io.MultiWriter(f, b)
+	}
+	_, err = io.Copy(w, p.Stdout)
 	if err != nil {
 		return
 	}
-	w, err := p.Wait(0)
+	wait, err := p.Wait(0)
 	if err != nil {
 		return
 	}
-	return b.String(), w.WaitStatus.ExitStatus(), nil
+	return b.String(), wait.WaitStatus.ExitStatus(), nil
 }
 
 // Find bin in PATH if a relative or absolute path hasn't been specified

misc/dashboard/builder/hg.go

@@ -45,7 +45,7 @@ func getCommit(rev string) (c Commit, err os.Error) {
 
 func getCommitParts(rev string) (parts []string, err os.Error) {
 	const format = "{rev}>{node}>{author|escape}>{date}>{desc}"
-	s, _, err := runLog(nil, goroot,
+	s, _, err := runLog(nil, "", goroot,
 		"hg", "log", "-r", rev, "-l", "1", "--template", format)
 	if err != nil {
 		return

misc/dashboard/builder/main.go

@@ -82,7 +82,7 @@ func main() {
 	if *buildRevision != "" {
 		c, err := getCommit(*buildRevision)
 		if err != nil {
-			log.Exit("Error finding revision:", err)
+			log.Exit("Error finding revision: ", err)
 		}
 		for _, b := range builders {
 			if err := b.buildCommit(c); err != nil {
@@ -138,7 +138,8 @@ func runBenchmark(r BenchRequest) {
 		"GOARCH=" + r.builder.goarch,
 		"PATH=" + bin + ":" + os.Getenv("PATH"),
 	}
-	benchLog, _, err := runLog(env, pkg, "gomake", "bench")
+	logfile := path.Join(r.path, "bench.log")
+	benchLog, _, err := runLog(env, logfile, pkg, "gomake", "bench")
 	if err != nil {
 		log.Println(r.builder.name, "gomake bench:", err)
 		return
@@ -195,7 +196,6 @@ func (b *Builder) build() bool {
 	if c == nil {
 		return false
 	}
-	log.Println(b.name, "building", c.num)
 	err = b.buildCommit(*c)
 	if err != nil {
 		log.Println(err)
@@ -233,6 +233,8 @@ func (b *Builder) buildCommit(c Commit) (err os.Error) {
 		}
 	}()
 
+	log.Println(b.name, "building", c.num)
+
 	// create place in which to do work
 	workpath := path.Join(buildroot, b.name+"-"+strconv.Itoa(c.num))
 	err = os.Mkdir(workpath, mkdirPerm)
@@ -269,7 +271,8 @@ func (b *Builder) buildCommit(c Commit) (err os.Error) {
 	srcDir := path.Join(workpath, "go", "src")
 
 	// build
-	buildLog, status, err := runLog(env, srcDir, *buildCmd)
+	logfile := path.Join(workpath, "build.log")
+	buildLog, status, err := runLog(env, logfile, srcDir, *buildCmd)
 	if err != nil {
 		return fmt.Errorf("all.bash: %s", err)
 	}
@@ -311,8 +314,7 @@ func (b *Builder) buildCommit(c Commit) (err os.Error) {
 		if err != nil {
 			return fmt.Errorf("tar: %s", err)
 		}
-		err = run(nil, workpath, "python",
-			path.Join(goroot, codePyScript),
+		err = run(nil, workpath, path.Join(goroot, codePyScript),
 			"-s", release,
 			"-p", codeProject,
 			"-u", b.codeUsername,