misc/docker: Go1.5 update + related simplifications

Update our Go image to use Go1.5.

Also, with Go1.5, we can compile static binaries (with CGO_ENABLED=0 and
--tags=netgo) without having to first rebuild Go itself from source with
CGO_ENABLED=0.

Finally, with Go1.5, we can now cross-compile straight outta the (linux)
binary tarball (without having to first build the necessary runtime in
src).

For both these above reasons, we don't need to use the Go -src tarball,
and we don't need to have a dedicated Go docker image for each GOOS we
cross-compile too.

Yay, progress!

Change-Id: Ibafb542a4771b151638e796ad3df78e0c8f1a4bf

misc/docker/dock.go

@@ -103,9 +103,6 @@ func genCamlistore(ctxDir string) {
 func genBinaries(ctxDir string) {
 	check(os.Mkdir(filepath.Join(ctxDir, "/camlistore.org"), 0755))
 	image := goDockerImage
-	if *buildOS != "linux" {
-		image += "-" + *buildOS
-	}
 	args := []string{
 		"run",
 		"--rm",
@@ -358,11 +355,10 @@ func main() {
 	// using docker all along, and it's convenient for now for code reuse. I
 	// can refactor it all out of dock.go afterwards if we like the process.
 	if *doBinaries {
-		goDir := "go"
-		if *buildOS != "linux" {
-			goDir = path.Join(goDir, *buildOS)
-		}
-		buildDockerImage(goDir, goDockerImage+"-"+*buildOS)
+		// TODO(mpl): consider using an "official" or trusted existing
+		// Go docker image, since we don't do anything special anymore in
+		// ours?
+		buildDockerImage("go", goDockerImage+"-linux")
 		ctxDir, err := ioutil.TempDir("", "camli-build")
 		if err != nil {
 			log.Fatal(err)

misc/docker/go/Dockerfile

@@ -7,11 +7,6 @@ RUN apt-get -y --no-install-recommends install ca-certificates libc6-dev
 
 # Get Go stable release
 WORKDIR /tmp
-# TODO(mpl): good enough for now with binary version. switch back to src tarball when go1.5 is out, if needed.
-RUN curl -O https://storage.googleapis.com/golang/go1.5rc1.linux-amd64.tar.gz
-RUN echo '2abf55effd93f5c2dcef306eaf14d3e7f614a407  go1.5rc1.linux-amd64.tar.gz' | sha1sum -c
-RUN tar -C /usr/local -xzf go1.5rc1.linux-amd64.tar.gz
-
-# rebuild Go with cgo disabled so we can build static binaries
-#WORKDIR /usr/local/go/src
-#RUN CGO_ENABLED=0 GOARCH=amd64 GOOS=linux ./make.bash
+RUN curl -O https://storage.googleapis.com/golang/go1.5.1.linux-amd64.tar.gz
+RUN echo '46eecd290d8803887dec718c691cc243f2175fe0  go1.5.1.linux-amd64.tar.gz' | sha1sum -c
+RUN tar -C /usr/local -xzf go1.5.1.linux-amd64.tar.gz

misc/docker/go/darwin/Dockerfile

@@ -1,4 +0,0 @@
-# Copyright 2015 The Camlistore Authors.
-FROM camlistore/go
-WORKDIR /usr/local/go/src
-RUN CGO_ENABLED=0 GOARCH=amd64 GOOS=darwin ./make.bash --no-clean

misc/docker/release/build-binaries.go

@@ -118,6 +118,7 @@ func fetchCamliSrc() {
 func build() {
 	check(os.Chdir("/gopath/src/camlistore.org"))
 	oldPath := os.Getenv("PATH")
+	// Note: no need to set GO15VENDOREXPERIMENT because make.go does it.
 	os.Setenv("GOPATH", "/gopath")
 	os.Setenv("PATH", "/usr/local/go/bin:"+oldPath)
 	cmd := exec.Command("go", "run", "make.go", "--use_gopath", "--os", *buildOS)