Fix backup Makefile and auth (knative#342)

* Fix backup Makefile and auth

Apparently "works on my machine" isn't enough.

1. The Makefile was broken, use the current directory for the build
context.
2. Activate the service account (not necessary for gcrane, but necessary
for gsutil).

* Get service account key from env

* For backup image, pass keyfile as first argument

ci/prow/config.yaml

@@ -1917,7 +1917,9 @@ periodics:
       imagePullPolicy: Always
       command:
       - "/backup.sh"
-
+      args:
+      - "/etc/backup-account/service-account.json"
+
 postsubmits:
   knative/serving:
   - name: post-knative-serving-go-coverage

images/backups/Dockerfile

@@ -21,6 +21,4 @@ LABEL maintainer "Jon Johnson <jonjohnson@google.com>"
 COPY --from=gcrane /ko-app /bin/gcrane
 
 # Copy the entrypoint shell script.
-COPY . .
-
-ENTRYPOINT ["/backup.sh"]
+ADD . .

images/backups/Makefile

@@ -18,7 +18,7 @@ TAG := $(shell date +v%Y%m%d)-$(shell git describe --always --dirty --match '^$$
 all: build
 
 build:
-	docker build -t $(IMG):$(TAG) -f Dockerfile ../..
+	docker build -t $(IMG):$(TAG) -f Dockerfile .
 	docker tag $(IMG):$(TAG) $(IMG):latest
 
 push_versioned: build

images/backups/backup.sh

@@ -17,6 +17,9 @@
 # This is a script to backup knative released images and yaml to the
 # knative-backups project.
 
+echo "Activating service account"
+gcloud auth activate-service-account --key-file=$1
+
 echo "Copying images"
 gcrane cp -r gcr.io/knative-releases gcr.io/knative-backups