Squashed 'hack/libbuild/' changes from 5e13446a..6274f165

6274f165 fix TAG_STRATEGY: unbound variable (#19)
46c48326 Remove gopath static flags.
637d3545 Fix reproducible build and add tags for static.

git-subtree-dir: hack/libbuild
git-subtree-split: 6274f1651a34103aeb545f5289c98d050e825ff1

common/lib.sh

@@ -91,7 +91,7 @@ detect_tag() {
   echo "commit_timestamp = $commit_timestamp"
 
   # write TAG info to a file so that it can be loaded by a different command or script
-  if [ "$1" != '' ]; then
+  if [ $# -gt 0 ] && [ "$1" != '' ]; then
     cat >"$1" <<EOL
 TAG=$TAG
 TAG_STRATEGY=$TAG_STRATEGY
@@ -136,7 +136,7 @@ hub_canary() {
   hub_up
 
   # ref: https://www.gnu.org/software/bash/manual/html_node/Conditional-Constructs.html#Conditional-Constructs
-  if [[ "$TAG_STRATEGY" == "commit_hash" && "$git_branch" == "master" ]]; then
+  if [[ "${TAG_STRATEGY:-}" == "commit_hash" && "${git_branch:-}" == "master" ]]; then
     local cmd="docker tag $DOCKER_REGISTRY/$IMG:$TAG $DOCKER_REGISTRY/$IMG:canary"
     echo $cmd
     $cmd

libbuild.py

@@ -174,13 +174,15 @@ def go_build(name, goos, goarch, main, compress=False, upx=False):
     if linker_opts:
         ldflags = "-ldflags '{}'".format(' '.join(linker_opts))
 
+    tags = "-tags 'osusergo netgo static_build'"
+
     bindir = 'dist/{name}'.format(name=name)
     if not os.path.isdir(bindir):
         os.makedirs(bindir)
     if goos == 'alpine':
         repo_dir = REPO_ROOT[len(GOPATH):]
         uid = check_output('id -u').strip()
-        cmd = "docker run --rm -u {uid} -v /tmp:/.cache -v {repo_root}:/go{repo_dir} -w /go{repo_dir} -e {cgo_env} golang:1.9-alpine {goc} build -o {bindir}/{name}-{goos}-{goarch}{ext} {cgo} {ldflags} {main}".format(
+        cmd = "docker run --rm -u {uid} -v /tmp:/.cache -v {repo_root}:/go{repo_dir} -w /go{repo_dir} -e {cgo_env} golang:1.9-alpine {goc} build -o {bindir}/{name}-{goos}-{goarch}{ext} {cgo} {ldflags} {tags} {main}".format(
             repo_root=REPO_ROOT,
             repo_dir=repo_dir,
             uid=uid,
@@ -192,11 +194,12 @@ def go_build(name, goos, goarch, main, compress=False, upx=False):
             cgo_env=cgo_env,
             cgo=cgo,
             ldflags=ldflags,
+            tags=tags,
             ext='.exe' if goos == 'windows' else '',
             main=main
         )
     else:
-        cmd = "GOOS={goos} GOARCH={goarch} {cgo_env} {goc} build -o {bindir}/{name}-{goos}-{goarch}{ext} {cgo} {ldflags} {main}".format(
+        cmd = "GOOS={goos} GOARCH={goarch} {cgo_env} {goc} build -o {bindir}/{name}-{goos}-{goarch}{ext} {cgo} {ldflags} {tags} {main}".format(
             name=name,
             goc=GOC,
             goos=goos,
@@ -205,6 +208,7 @@ def go_build(name, goos, goarch, main, compress=False, upx=False):
             cgo_env=cgo_env,
             cgo=cgo,
             ldflags=ldflags,
+            tags=tags,
             ext='.exe' if goos == 'windows' else '',
             main=main
         )