use latest tag before non-release version (#164)

Updates the `build-controller-release.sh` script to check for the latest
Git tag on the target service controller repository before defaulting
the RELEASE_VERSION to `v0.0.0-non-release-version`. This allows
developers to regenerate their service controllers with new ACK runtimes
without overwriting the static manifests' image versions from the latest
published Git tag to `v0.0.0-non-release-version`. For service
controllers that have yet to release any images, the
`v0.0.0-non-release-version` continues to be used.

Before this patch:

```
[jaypipes@thelio code-generator]$ make build-controller SERVICE=rds
building ack-generate ... ok.
==== building rds-controller ====
Copying common custom resource definitions into rds
Building Kubernetes API objects for rds
Generating deepcopy code for rds
Generating custom resource definitions for rds
Building service controller for rds
Generating RBAC manifests for rds
Running gofmt against generated code for rds
==== building rds-controller release artifacts ====
Building release artifacts for rds-v0.0.0-non-release-version
Generating common custom resource definitions
Generating custom resource definitions for rds
Generating RBAC manifests for rds
```

After this patch:

```
[jaypipes@thelio code-generator]$ make build-controller SERVICE=rds
building ack-generate ... ok.
==== building rds-controller ====
Copying common custom resource definitions into rds
Building Kubernetes API objects for rds
Generating deepcopy code for rds
Generating custom resource definitions for rds
Building service controller for rds
Generating RBAC manifests for rds
Running gofmt against generated code for rds
==== building rds-controller release artifacts ====
Building release artifacts for rds-v0.0.4
Generating common custom resource definitions
Generating custom resource definitions for rds
Generating RBAC manifests for rds
```

Note that at this time, the RDS controller's latest published image is
`v0.0.4`.

Issue aws-controllers-k8s/community#912

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Author: jaypipes

scripts/build-controller-release.sh

@@ -41,19 +41,7 @@ TEMPLATES_DIR=${TEMPLATES_DIR:-$DEFAULT_TEMPLATES_DIR}
 DEFAULT_RUNTIME_DIR="$ROOT_DIR/../runtime"
 RUNTIME_DIR=${RUNTIME_DIR:-$DEFAULT_RUNTIME_DIR}
 RUNTIME_API_VERSION=${RUNTIME_API_VERSION:-"v1alpha1"}
-DEFAULT_RELEASE_VERSION="v0.0.0-non-release-version"
-# If the release version is not provided, use "v0.0.0-non-release-version".
-# This non-release version will allow generation of release artifacts and
-# executing presubmit 'release-test' job on those artifacts.
-# ACK postsubmit release job makes sure this version does not get released to
-# public ecr repository.
-#
-# Using a static non-release version works because this is only a placeholder
-# value which gets replaced during presubmit 'release-test' job. Having a
-# default non-release value also helps AWS service teams to develop the
-# controller without worrying about the version until actual controller
-# release.
-RELEASE_VERSION=${RELEASE_VERSION:-$DEFAULT_RELEASE_VERSION}
+NON_RELEASE_VERSION="v0.0.0-non-release-version"
 
 USAGE="
 Usage:
@@ -142,7 +130,25 @@ if [[ ! -d $SERVICE_CONTROLLER_SOURCE_PATH ]]; then
     exit 1
 fi
 
-if [[ $RELEASE_VERSION != $DEFAULT_RELEASE_VERSION ]]; then
+# If the release version is not provided, check if the source controller
+# repository has a Git tag on it. If it does, use that as the version. If it
+# does not, use "v0.0.0-non-release-version".
+#
+# This non-release version will allow generation of release artifacts and
+# executing presubmit 'release-test' job on those artifacts.
+# ACK postsubmit release job makes sure this version does not get released to
+# public ecr repository.
+#
+# Using a static non-release version works because this is only a placeholder
+# value which gets replaced during presubmit 'release-test' job. Having a
+# default non-release value also helps AWS service teams to develop the
+# controller without worrying about the version until actual controller
+# release.
+pushd $SERVICE_CONTROLLER_SOURCE_PATH 1>/dev/null
+    RELEASE_VERSION=${RELEASE_VERSION:-`git describe --tags --abbrev=0 2>/dev/null || echo $NON_RELEASE_VERSION`}
+popd 1>/dev/null
+
+if [[ $RELEASE_VERSION != $NON_RELEASE_VERSION ]]; then
   # validate that release version is in the format vx.y.z , where x,y,z are
   # positive real numbers
   if ! (echo "$RELEASE_VERSION" | grep -Eq "^v[0-9]+\.[0-9]+\.[0-9]+$"); then
@@ -246,4 +252,4 @@ if [[ $ACK_GENERATE_OLM == "true" ]]; then
     fi
 
     $ACK_GENERATE_BIN_PATH olm $ag_olm_args
-fi
+fi