Adds make-release script, static k8s manifests (#132)

Closes #75.  

### Changelog 

Adds 4 scripts to the `hack/` directory for building/pushing images, injecting images tags into static manifests, and tagging new releases. See [hack/README.md](https://github.com/m-okeefe/microservices-demo/tree/release-script/hack). 

**Note**: since we have not pushed images yet, the images in the `./release/` manifests are still set to the skaffold defaults (eg. `adservice`).

README.md

@@ -144,6 +144,21 @@ Find **Protocol Buffers Descriptions** at the [`./pb` directory](./pb).
     are seeing this, run `kubectl get service frontend-external -o=yaml | kubectl apply -f-`
     to trigger load balancer reconfiguration.
 
+### Option 3: Using Static Images 
+
+> 💡 Recommended for test-driving the application on an existing cluster. 
+
+**Prerequisite**: a running Kubernetes cluster. 
+
+1. Clone this repository.
+1. Deploy the application: `kubectl apply -f ./release/kubernetes-manifests`  
+1. Run `kubectl get pods` to see pods are in a healthy and ready state.
+1.  Find the IP address of your application, then visit the application on your
+    browser to confirm installation.
+
+        kubectl get service frontend-external
+
+
 ### (Optional) Deploying on a Istio-installed GKE cluster
 
 > **Note:** you followed GKE deployment steps above, run `skaffold delete` first

hack/README.md

@@ -0,0 +1,18 @@
+## `hack/` 
+
+This directory provides scripts for building and pushing Docker images, and tagging new demo
+releases. 
+
+### env variables 
+
+- `TAG` - git release tag / Docker tag. 
+- `REPO_PREFIX` - Docker repo prefix to push images. Format: `$user/$project`.  Resulting images will be of the
+  format `$user/$project/$svcname:$tag` (where `svcname` = `adservice`, `cartservice`,
+  etc.)
+
+### scripts 
+
+1. `./make-docker-images.sh`: builds and pushes images to the specified Docker repository.
+2. `./make-release-artifacts.sh`: generates a combined YAML file with image $TAG at: 
+   `./release/kubernetes-manifests/demo.yaml`. 
+3. `./make-release.sh`: runs scripts 1 and 2, then runs `git tag` / pushes updated manifests to master.

hack/make-docker-images.sh

@@ -0,0 +1,39 @@
+# Copyright 2019 Google LLC
+#
+# 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.
+
+# Builds and pushes docker image for each demo microservice. 
+
+#!/usr/bin/env bash
+set -euo pipefail
+
+log() { echo "$1" >&2; }
+fail() { log "$1"; exit 1; }
+
+TAG="${TAG?TAG env variable must be specified}"
+REPO_PREFIX="${REPO_PREFIX?REPO_PREFIX env variable must be specified}"
+
+
+for dir in ./src/*/    
+do
+    # build image  
+    svcname="$(basename $dir)"
+    image="$REPO_PREFIX/$svcname:$TAG"
+    echo "Building and pushing $image..." 
+    docker build -t $image -f $dir/Dockerfile $dir 
+
+    # push image 
+    docker push $image 
+done
+
+log "Successfully built and pushed images."

hack/make-release-artifacts.sh

@@ -0,0 +1,55 @@
+# Copyright 2019 Google LLC
+#
+# 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.
+
+# injects new image/tag into the images in ./release/kubernetes-manifests/demo.yaml 
+
+#!/usr/bin/env bash
+set -euo pipefail
+
+log() { echo "$1" >&2; }
+fail() { log "$1"; exit 1; }
+
+TAG="${TAG?TAG env variable must be specified}"
+REPO_PREFIX="${REPO_PREFIX?REPO_PREFIX env variable must be specified}"
+
+# overwrite release/ with the latest manifests, adding "---" separator.
+src="./kubernetes-manifests/*"
+manifestfile="./release/kubernetes-manifests/demo.yaml"
+tmp="./release/kubernetes-manifests/tmp.yaml"
+[ -e $manifestfile ] && rm $manifestfile
+for f in $src; do (cat "${f}"; echo "---") >> $tmp; done
+
+# remove extra google headers 
+gsed -i '/^#/d' $tmp 
+
+# remove empty lines 
+gsed -r -i '/^\s*$/d' $tmp 
+
+# add 1 google header to the top 
+cat "./release/.googleheader" $tmp > $manifestfile 
+rm $tmp 
+
+
+# replace image repo, tag for each deployment  
+for dir in ./src/*/    
+do
+    svcname="$(basename $dir)"
+    image="$REPO_PREFIX/$svcname:$TAG"
+
+    pattern="^(\s*)image:\s.*$svcname(.*)(\s*)"
+    replace="\1image: $image\3"  
+    gsed -r -i "s|$pattern|$replace|g" $manifestfile
+done
+
+log "Successfully added image tags > wrote to demo.yaml".

hack/make-release.sh

@@ -0,0 +1,41 @@
+# Copyright 2019 Google LLC
+#
+# 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.
+
+# Creates a new release by 1) building/pushing images, 2) injecting tag into YAML, 
+# 3) creating a new git tag, and 4) pushing tags/updated YAML to $BRANCH.
+
+#!/usr/bin/env bash
+set -euo pipefail
+
+log() { echo "$1" >&2; }
+fail() { log "$1"; exit 1; }
+
+TAG="${TAG?TAG env variable must be specified}"
+REPO_PREFIX="${REPO_PREFIX?REPO_PREFIX env variable must be specified}"
+
+# build and push images 
+./hack/make-docker-images.sh
+
+# update yaml 
+./hack/make-release-artifacts.sh 
+
+# create git release / push to master 
+log "Pushing k8s manifests to master..."
+git tag "$TAG"
+git add release/
+git commit --allow-empty -m "Release $TAG"
+git push --tags
+git push origin master
+
+log "Successfully tagged release $TAG."

release/.googleheader

@@ -0,0 +1,13 @@
+# Copyright 2019 Google LLC
+#
+# 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.