Rework hack/ and build/ directories.

* Rewrite a bunch of the hack/ directory with modular reusable bash libraries.
* Have 'build/*' build on 'hack/*'.  The stuff in build now just runs hack/* in a docker container.
* Use a docker data container to enable faster incremental builds.
* Standardize output to _output/{local,dockerized}/bin/OS/ARCH/*.  This regularized placement makes cross compilation work.
* Move travis specific scripts under hack/travis

With new dockerized incremental builds, I can do a no-op `make quick-release` in ~30s.  This is a significant improvement.

hack/lib/version.sh

@@ -0,0 +1,126 @@
+#!/bin/bash
+
+# Copyright 2014 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Version management helpers.  These functions help to set, save and load the
+# following variables:
+#
+#    KUBE_GIT_COMMIT - The git commit id corresponding to this
+#          source code.
+#    KUBE_GIT_TREE_STATE - "clean" indicates no changes since the git commit id
+#        "dirty" indicates source code changes after the git commit id
+#    KUBE_GIT_VERSION - "vX.Y" used to indicate the last release version.
+#    KUBE_GIT_MAJOR - The major part of the version
+#    KUBE_GIT_MINOR - The minor component of the version
+
+# Grovels through git to set a set of env variables.
+#
+# If KUBE_GIT_VERSION_FILE, this function will load from that file instead of
+# querying git.
+kube::version::get_version_vars() {
+  if [[ -n ${KUBE_GIT_VERSION_FILE-} ]]; then
+    kube::version::load_version_vars "${KUBE_GIT_VERSION_FILE}"
+    return
+  fi
+
+  local git=(git --work-tree "${KUBE_ROOT}")
+
+  if [[ -n ${KUBE_GIT_COMMIT-} ]] || KUBE_GIT_COMMIT=$("${git[@]}" rev-parse "HEAD^{commit}" 2>/dev/null); then
+    if [[ -z ${KUBE_GIT_TREE_STATE-} ]]; then
+      # Check if the tree is dirty.  default to dirty
+      if git_status=$("${git[@]}" status --porcelain 2>/dev/null) && [[ -z ${git_status} ]]; then
+        KUBE_GIT_TREE_STATE="clean"
+      else
+        KUBE_GIT_TREE_STATE="dirty"
+      fi
+    fi
+
+    # Use git describe to find the version based on annotated tags.
+    if [[ -n ${KUBE_GIT_VERSION-} ]] || KUBE_GIT_VERSION=$("${git[@]}" describe --abbrev=14 "${KUBE_GIT_COMMIT}^{commit}" 2>/dev/null); then
+      if [[ "${KUBE_GIT_TREE_STATE}" == "dirty" ]]; then
+        # git describe --dirty only considers changes to existing files, but
+        # that is problematic since new untracked .go files affect the build,
+        # so use our idea of "dirty" from git status instead.
+        KUBE_GIT_VERSION+="-dirty"
+      fi
+
+      # Try to match the "git describe" output to a regex to try to extract
+      # the "major" and "minor" versions and whether this is the exact tagged
+      # version or whether the tree is between two tagged versions.
+      if [[ "${KUBE_GIT_VERSION}" =~ ^v([0-9]+)\.([0-9]+)([.-].*)?$ ]]; then
+        KUBE_GIT_MAJOR=${BASH_REMATCH[1]}
+        KUBE_GIT_MINOR=${BASH_REMATCH[2]}
+        if [[ -n "${BASH_REMATCH[3]}" ]]; then
+          KUBE_GIT_MINOR+="+"
+        fi
+      fi
+    fi
+  fi
+}
+
+# Saves the environment flags to $1
+kube::version::save_version_vars() {
+  local version_file=${1-}
+  [[ -n ${version_file} ]] || {
+    echo "!!! Internal error.  No file specified in kube::version::save_version_vars"
+    return 1
+  }
+
+  cat <<EOF >"${version_file}"
+KUBE_GIT_COMMIT='${KUBE_GIT_COMMIT-}'
+KUBE_GIT_TREE_STATE='${KUBE_GIT_TREE_STATE-}'
+KUBE_GIT_VERSION='${KUBE_GIT_VERSION-}'
+KUBE_GIT_MAJOR='${KUBE_GIT_MAJOR-}'
+KUBE_GIT_MINOR='${KUBE_GIT_MINOR-}'
+EOF
+}
+
+# Loads up the version variables from file $1
+kube::version::load_version_vars() {
+  local version_file=${1-}
+  [[ -n ${version_file} ]] || {
+    echo "!!! Internal error.  No file specified in kube::version::load_version_vars"
+    return 1
+  }
+
+  source "${version_file}"
+}
+
+# Prints the value that needs to be passed to the -ldflags parameter of go build
+# in order to set the Kubernetes based on the git tree status.
+kube::version::ldflags() {
+  kube::version::get_version_vars
+
+  local -a ldflags=()
+  if [[ -n ${KUBE_GIT_COMMIT-} ]]; then
+    ldflags+=(-X "${KUBE_GO_PACKAGE}/pkg/version.gitCommit" "${KUBE_GIT_COMMIT}")
+    ldflags+=(-X "${KUBE_GO_PACKAGE}/pkg/version.gitTreeState" "${KUBE_GIT_TREE_STATE}")
+  fi
+
+  if [[ -n ${KUBE_GIT_VERSION-} ]]; then
+    ldflags+=(-X "${KUBE_GO_PACKAGE}/pkg/version.gitVersion" "${KUBE_GIT_VERSION}")
+  fi
+
+  if [[ -n ${KUBE_GIT_MAJOR-} && -n ${KUBE_GIT_MINOR-} ]]; then
+    ldflags+=(
+      -X "${KUBE_GO_PACKAGE}/pkg/version.gitMajor" "${KUBE_GIT_MAJOR}"
+      -X "${KUBE_GO_PACKAGE}/pkg/version.gitMinor" "${KUBE_GIT_MINOR}"
+    )
+  fi
+
+  # The -ldflags parameter takes a single string, so join the output.
+  echo "${ldflags[*]-}"
+}