Add dynbinary and dyntest scripts for building/testing a separate static dockerinit binary

After a nice long brainstorming session with @shykes on IRC, we decided on using a SHA1 hash of dockerinit compiled into the dynamic docker binary to ensure that we always use the two in a perfect pair, and never mix and match.

hack/PACKAGERS.md

@@ -90,6 +90,16 @@ You would do the users of your distro a disservice and "void the docker warranty
 A good comparison is Busybox: all distros package it as a statically linked binary, because it just
 makes sense. Docker is the same way.
 
+If you *must* have a non-static Docker binary, please use:
+
+```bash
+./hack/make.sh dynbinary
+```
+
+This will create *./bundles/$VERSION/dynbinary/docker-$VERSION* and *./bundles/$VERSION/binary/dockerinit-$VERSION*.
+The first of these would usually be installed at */usr/bin/docker*, while the second must be installed
+at */usr/libexec/docker/dockerinit*.
+
 ## Testing Docker
 
 Before releasing your binary, make sure to run the tests! Run the following command with the source

hack/make.sh

@@ -35,6 +35,8 @@ grep -q "$RESOLVCONF" /proc/mounts || {
 DEFAULT_BUNDLES=(
 	binary
 	test
+	dynbinary
+	dyntest
 	ubuntu
 )
 
@@ -46,6 +48,7 @@ fi
 
 # Use these flags when compiling the tests and final binary
 LDFLAGS='-X main.GITCOMMIT "'$GITCOMMIT'" -X main.VERSION "'$VERSION'" -w'
+LDFLAGS_STATIC='-X github.com/dotcloud/docker/utils.IAMSTATIC true -linkmode external -extldflags "-lpthread -static -Wl,--unresolved-symbols=ignore-in-object-files"'
 BUILDFLAGS='-tags netgo'
 
 bundle() {

hack/make/binary

@@ -2,5 +2,5 @@
 
 DEST=$1
 
-go build -o $DEST/docker-$VERSION -ldflags "$LDFLAGS -linkmode external -extldflags \"-lpthread -static -Wl,--unresolved-symbols=ignore-in-object-files\"" $BUILDFLAGS ./docker
+go build -o $DEST/docker-$VERSION -ldflags "$LDFLAGS $LDFLAGS_STATIC" $BUILDFLAGS ./docker
 echo "Created binary: $DEST/docker-$VERSION"

hack/make/dynbinary

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+DEST=$1
+
+# dockerinit still needs to be a static binary, even if docker is dynamic
+CGO_ENABLED=0 go build -a -o $DEST/dockerinit-$VERSION -ldflags "$LDFLAGS -d" $BUILDFLAGS ./dockerinit
+echo "Created binary: $DEST/dockerinit-$VERSION"
+ln -sf dockerinit-$VERSION $DEST/dockerinit
+
+# sha1 our new dockerinit to ensure separate docker and dockerinit always run in a perfect pair compiled for one another
+export DOCKER_INITSHA1="$(sha1sum $DEST/dockerinit-$VERSION | cut -d' ' -f1)"
+# exported so that "dyntest" can easily access it later without recalculating it
+
+go build -o $DEST/docker-$VERSION -ldflags "$LDFLAGS -X github.com/dotcloud/docker/utils.INITSHA1 \"$DOCKER_INITSHA1\"" $BUILDFLAGS ./docker
+echo "Created binary: $DEST/docker-$VERSION"

hack/make/dyntest

@@ -0,0 +1,41 @@
+#!/bin/sh
+
+DEST=$1
+INIT=$DEST/../dynbinary/dockerinit-$VERSION
+
+set -e
+
+if [ ! -x "$INIT" ]; then
+	echo >&2 'error: dynbinary must be run before dyntest'
+	false
+fi
+
+# Run Docker's test suite, including sub-packages, and store their output as a bundle
+# If $TESTFLAGS is set in the environment, it is passed as extra arguments to 'go test'.
+# You can use this to select certain tests to run, eg.
+# 
+# 	TESTFLAGS='-run ^TestBuild$' ./hack/make.sh test
+#
+bundle_test() {
+	{
+		date
+		for test_dir in $(find_test_dirs); do (
+			set -x
+			cd $test_dir
+			export TEST_DOCKERINIT_PATH=$DEST/../dynbinary/dockerinit-$VERSION
+			go test -v -ldflags "$LDFLAGS -X github.com/dotcloud/docker/utils.INITSHA1 \"$DOCKER_INITSHA1\"" $BUILDFLAGS
+		)  done
+	} 2>&1 | tee $DEST/test.log
+}
+
+
+# This helper function walks the current directory looking for directories
+# holding Go test files, and prints their paths on standard output, one per
+# line.
+find_test_dirs() {
+       find . -name '*_test.go' | grep -v '^./vendor' |
+               { while read f; do dirname $f; done; } |
+               sort -u
+}
+
+bundle_test

hack/make/test

@@ -17,7 +17,7 @@ bundle_test() {
 			set -x
 			cd $test_dir
 			go test -i
-			go test -v -ldflags "$LDFLAGS -linkmode external -extldflags \"-lpthread -static -Wl,--unresolved-symbols=ignore-in-object-files\"" $BUILDFLAGS $TESTFLAGS
+			go test -v -ldflags "$LDFLAGS $LDFLAGS_STATIC" $BUILDFLAGS $TESTFLAGS
 		)  done
 	} 2>&1 | tee $DEST/test.log
 }