feat: immutable digest for the most specific tags (#113)

Detect updates of the Dockerfile template and Barman python
dependencies, and increase the imageReleaseVersion accordingly.
Avoid pushing an image if its most specific tag (fullTag)
already exists, thus preventing the override of the
existing digest.

Signed-off-by: Niccolò Fei <niccolo.fei@enterprisedb.com>

lib/repo_funcs.sh

@@ -90,6 +90,14 @@ generate_postgres() {
 		pipOptions="--break-system-packages"
 	fi
 
+	dockerTemplate="Dockerfile.template"
+	if [[ ${version} -gt "${POSTGRESQL_LATEST_MAJOR_RELEASE}" ]]; then
+		dockerTemplate="Dockerfile-beta.template"
+	fi
+
+	# Update requirements.txt
+	echo "$requirements" > "$versionDir/requirements.txt"
+
 	# Output the image being updated
 	echo "$postgresImageVersion"
 
@@ -111,9 +119,9 @@ generate_postgres() {
 
 	newRelease="false"
 
-	# Detect if postgres image updated
+	# Detect an update of the postgres image
 	if [ "$oldPostgresImageLastUpdate" != "$postgresImageLastUpdate" ]; then
-		echo "Debian Image changed from $oldPostgresImageLastUpdate to $postgresImageLastUpdate"
+		echo "Postgres image timestamp changed from $oldPostgresImageLastUpdate to $postgresImageLastUpdate"
 		newRelease="true"
 		record_version "${versionFile}" "POSTGRES_IMAGE_LAST_UPDATED" "${postgresImageLastUpdate}"
 	fi
@@ -125,6 +133,18 @@ generate_postgres() {
 		record_version "${versionFile}" "BARMAN_VERSION" "${barmanVersion}"
 	fi
 
+	# Detect an update of Dockerfile template
+	if [[ -n $(git diff --name-status "$dockerTemplate") ]]; then
+		echo "Detected update of $dockerTemplate"
+		newRelease="true"
+	fi
+
+	# Detect an update of requirements.txt
+	if [[ -n $(git diff --name-status "$versionDir/requirements.txt") ]]; then
+		echo "Detected update of requirements.txt dependencies"
+		newRelease="true"
+	fi
+
 	if [ "$oldPostgresImageVersion" != "$postgresImageVersion" ]; then
 		echo "PostgreSQL base image changed from $oldPostgresImageVersion to $postgresImageVersion"
 		record_version "${versionFile}" "IMAGE_RELEASE_VERSION" 1
@@ -135,12 +155,6 @@ generate_postgres() {
 		record_version "${versionFile}" "IMAGE_RELEASE_VERSION" $imageReleaseVersion
 	fi
 
-	dockerTemplate="Dockerfile.template"
-	if [[ ${version} -gt "${POSTGRESQL_LATEST_MAJOR_RELEASE}" ]]; then
-		dockerTemplate="Dockerfile-beta.template"
-	fi
-
-	echo "$requirements" > "$versionDir/requirements.txt"
 	sed -e 's/%%POSTGRES_IMAGE_VERSION%%/'"$postgresImageVersion"'/g' \
 		-e 's/%%IMAGE_RELEASE_VERSION%%/'"$imageReleaseVersion"'/g' \
 		-e 's/%%PIP_OPTIONS%%/'"${pipOptions}"'/g' \