Add GCP Cloud SDK to Terraform deployer image (#638)

* update terraform deployer image

Terraform deployer image may need some additional Cloud Service Provider
specific tooling to handle corner cases not handled by Terraform itself.

In this case this commits adds support for `bq` tool from GCP Cloud SDK.

As `bq` and the entire GCP Cloud SDK requires python, is easy to add AWS
or Azure dedicated tooling in the future (as both are Python-based).

* install git and openssh

* skip using apk cache

* cleanup google cloud SDK archive

Author: endorama

internal/install/_static/Dockerfile.terraform_deployer

@@ -1,6 +1,24 @@
-FROM hashicorp/terraform:light
-ENV TF_IN_AUTOMATION=true
+FROM hashicorp/terraform:light as terraform
+
+FROM python:3-alpine
+
+# required by gcloud SDK
+RUN apk add --no-cache git openssh curl
+
+ENV GCLOUD_SDK_VERSION 367.0.0
+ENV PATH $PATH:/usr/local/gcloud/google-cloud-sdk/bin
+RUN curl "https://dl.google.com/dl/cloudsdk/channels/rapid/downloads/google-cloud-sdk-$GCLOUD_SDK_VERSION-linux-x86_64.tar.gz" > /tmp/google-cloud-sdk.tar.gz \
+  && mkdir -p /usr/local/gcloud \
+  && tar -C /usr/local/gcloud -xvf /tmp/google-cloud-sdk.tar.gz \
+  && /usr/local/gcloud/google-cloud-sdk/install.sh -q --override-components="bq" \
+  && rm /tmp/google-cloud-sdk.tar.gz
+
 HEALTHCHECK --timeout=3s CMD sh -c "[ -f /tmp/tf-applied ]"
+
+COPY --from=terraform /bin/terraform /usr/bin/terraform
+
+ENV TF_IN_AUTOMATION=true
 ADD run.sh /
 WORKDIR /workspace
+
 ENTRYPOINT sh /run.sh