move docker_tls_args into weaveutil

and also give users a clue what went wrong when docker isn't running

.gitignore

@@ -42,7 +42,6 @@ prog/weavewait/weavewait
 prog/weavewait/weavewait_noop
 prog/weavewait/weavewait_nomcast
 prog/weaveutil/weaveutil
-prog/docker_tls_args/docker_tls_args
 prog/plugin/plugin
 testing/cover/cover
 testing/runner/runner
@@ -60,7 +59,6 @@ prog/weaveexec/weavewait_noop
 prog/weaveexec/weavewait_nomcast
 prog/weaveexec/sigproxy
 prog/weaveexec/weaveutil
-prog/weaveexec/docker_tls_args
 prog/weaveexec/docker*.tgz
 Vagrantfile.local
 test/tls/tls

Makefile

@@ -16,12 +16,11 @@ WEAVEWAIT_EXE=prog/weavewait/weavewait
 WEAVEWAIT_NOOP_EXE=prog/weavewait/weavewait_noop
 WEAVEWAIT_NOMCAST_EXE=prog/weavewait/weavewait_nomcast
 WEAVEUTIL_EXE=prog/weaveutil/weaveutil
-DOCKERTLSARGS_EXE=prog/docker_tls_args/docker_tls_args
 DOCKERPLUGIN_EXE=prog/plugin/plugin
 RUNNER_EXE=tools/runner/runner
 TEST_TLS_EXE=test/tls/tls
 
-EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(DOCKERTLSARGS_EXE) $(DOCKERPLUGIN_EXE) $(TEST_TLS_EXE)
+EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(DOCKERPLUGIN_EXE) $(TEST_TLS_EXE)
 
 WEAVER_UPTODATE=.weaver.uptodate
 WEAVEEXEC_UPTODATE=.weaveexec.uptodate
@@ -82,11 +81,10 @@ $(WEAVEUTIL_EXE): prog/weaveutil/*.go
 # These next programs need separate rules as they fail the netgo check in
 # the main build stanza due to not importing net package
 $(SIGPROXY_EXE): prog/sigproxy/*.go
-$(DOCKERTLSARGS_EXE): prog/docker_tls_args/*.go
 $(DOCKERPLUGIN_EXE): prog/plugin/*.go plugin/net/*.go plugin/ipam/*.go plugin/skel/*.go api/*.go common/docker/*.go
 $(TEST_TLS_EXE): test/tls/*.go
 
-$(SIGPROXY_EXE) $(DOCKERTLSARGS_EXE) $(DOCKERPLUGIN_EXE) $(TEST_TLS_EXE):
+$(SIGPROXY_EXE) $(DOCKERPLUGIN_EXE) $(TEST_TLS_EXE):
 	go get -tags netgo ./$(@D)
 	go build $(BUILD_FLAGS) -o $@ ./$(@D)
 
@@ -106,7 +104,7 @@ $(WEAVER_UPTODATE): prog/weaver/Dockerfile $(WEAVER_EXE)
 	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker build -t $(WEAVER_IMAGE) prog/weaver
 	touch $@
 
-$(WEAVEEXEC_UPTODATE): prog/weaveexec/Dockerfile prog/weaveexec/symlink $(DOCKER_DISTRIB) weave $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(DOCKERTLSARGS_EXE)
+$(WEAVEEXEC_UPTODATE): prog/weaveexec/Dockerfile prog/weaveexec/symlink $(DOCKER_DISTRIB) weave $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE)
 	cp weave prog/weaveexec/weave
 	cp $(SIGPROXY_EXE) prog/weaveexec/sigproxy
 	cp $(WEAVEPROXY_EXE) prog/weaveexec/weaveproxy
@@ -114,7 +112,6 @@ $(WEAVEEXEC_UPTODATE): prog/weaveexec/Dockerfile prog/weaveexec/symlink $(DOCKER
 	cp $(WEAVEWAIT_NOOP_EXE) prog/weaveexec/weavewait_noop
 	cp $(WEAVEWAIT_NOMCAST_EXE) prog/weaveexec/weavewait_nomcast
 	cp $(WEAVEUTIL_EXE) prog/weaveexec/weaveutil
-	cp $(DOCKERTLSARGS_EXE) prog/weaveexec/docker_tls_args
 	cp $(DOCKER_DISTRIB) prog/weaveexec/docker.tgz
 	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker build -t $(WEAVEEXEC_IMAGE) prog/weaveexec
 	touch $@

prog/weaveexec/Dockerfile

@@ -20,7 +20,7 @@ RUN apk add --update \
   && rm -rf /var/cache/apk/*
 
 ADD ./weave ./sigproxy ./weaveproxy ./symlink /home/weave/
-ADD ./weaveutil ./docker_tls_args /usr/bin/
+ADD ./weaveutil /usr/bin/
 ADD ./weavewait /w/w
 ADD ./weavewait_noop /w-noop/w
 ADD ./weavewait_nomcast /w-nomcast/w

prog/weaveutil/docker_tls_args.go

@@ -13,14 +13,18 @@ import (
 	"strings"
 )
 
-func main() {
+func dockerTLSArgs(args []string) error {
+	if len(args) > 0 {
+		cmdUsage("docker-tls-args", "")
+	}
 	procRoot := os.Getenv("PROCFS")
 	if procRoot == "" {
 		procRoot = "/proc"
 	}
-
 	dirEntries, err := ioutil.ReadDir(procRoot)
-	checkErr(err)
+	if err != nil {
+		return err
+	}
 
 	for _, dirEntry := range dirEntries {
 		dirName := dirEntry.Name()
@@ -63,15 +67,8 @@ func main() {
 		}
 
 		fmt.Println(strings.Join(tlsArgs, " "))
-		os.Exit(0)
+		return nil
 	}
 
-	os.Exit(1)
-}
-
-func checkErr(err error) {
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
+	return fmt.Errorf("cannot locate running docker daemon")
 }

prog/weaveutil/main.go

@@ -10,8 +10,9 @@ var commands map[string]func([]string) error
 
 func init() {
 	commands = map[string]func([]string) error{
-		"help":     help,
-		"netcheck": netcheck,
+		"help":            help,
+		"netcheck":        netcheck,
+		"docker-tls-args": dockerTLSArgs,
 	}
 }
 

weave

@@ -1434,8 +1434,8 @@ proxy_args() {
     PROXY_HOST=""
     proxy_parse_args "$@"
 
-    if [ -z "$PROXY_TLS_ENABLED" -a -z "$PROXY_TLS_DETECTION_DISABLED" ] && command_exists docker_tls_args ; then
-        if ! DOCKER_TLS_ARGS=$(docker_tls_args) ; then
+    if [ -z "$PROXY_TLS_ENABLED" -a -z "$PROXY_TLS_DETECTION_DISABLED" ] && command_exists weaveutil ; then
+        if ! DOCKER_TLS_ARGS=$(weaveutil docker-tls-args) ; then
             echo "Unable to auto-detect proxy TLS configuration; you must launch the proxy with" >&2
             echo "'weave launch-proxy' and supply '--no-detect-tls' or TLS options." >&2
             exit 1