Other: Improve check-drone-drift script (#5925)

* Improve check-drone-drift script

Instead of checking the line count of the current branch an main, run
`make drone` and check if there are changes to the target
`.drone/drone.yml` file.

Signed-off-by: Christian Haudum <christian.haudum@gmail.com>

* Generate .drone/drone.yml using `make drone`

Signed-off-by: Christian Haudum <christian.haudum@gmail.com>

* fixup! Generate .drone/drone.yml using `make drone`

Signed-off-by: Christian Haudum <christian.haudum@gmail.com>

.drone/drone.yml

@@ -12,7 +12,7 @@ steps:
       from_secret: docker_password
     repo: grafana/loki-build-image
     tags:
-    - 0.20.2
+    - 0.20.3
     username:
       from_secret: docker_username
   when:
@@ -1118,6 +1118,6 @@ kind: secret
 name: deploy_config
 ---
 kind: signature
-hmac: 2f47de5e61231501593c473c31c46c695edabd18e6dd5e06817d272720c144f8
+hmac: 64871d70248fbe43acab816fe107dc657442ded224b48779ac15f4559143a2c6
 
 ...

Makefile

@@ -576,7 +576,7 @@ else
 endif
 
 check-drone-drift:
-	./tools/check-drone-drift.sh main
+	./tools/check-drone-drift.sh $(BUILD_IMAGE_VERSION)
 
 
 # support go modules

tools/check-drone-drift.sh

@@ -4,18 +4,30 @@ set -uo pipefail
 
 command -v drone >/dev/null 2>&1 || { echo "drone is not installed"; exit 1; }
 
-TARGET_BRANCH="$1"
 DRONE_JSONNET_FILE=".drone/drone.jsonnet"
 DRONE_CONFIG_FILE=".drone/drone.yml"
+DRONE_ACTUAL_CONFIG_FILE="$(mktemp)"
+DRONE_EXPECTED_CONFIG_FILE="$(mktemp)"
 
 # Check for a drift between the jsonnet and the resulting file consumed by Drone
-modified_drone_jsonnet=$(git diff "${TARGET_BRANCH}" -- "${DRONE_JSONNET_FILE}" | wc -l)
-  if [[ "${modified_drone_jsonnet}" -gt "0" ]]; then
-    modified_drone_config=$(git diff "${TARGET_BRANCH}" -- "${DRONE_CONFIG_FILE}" | wc -l)
-    if [[ "${modified_drone_config}" -lt "1" ]]; then
-      echo "There is a drift between ${DRONE_JSONNET_FILE} and ${DRONE_CONFIG_FILE}"
-      echo "You can fix it by running:"
-      echo "make drone"
-      exit 1
-    fi
-  fi
+drone jsonnet \
+    --stream \
+    --stdout \
+    --format \
+    -V __build-image-version="${1:-latest}" \
+    --source "${DRONE_JSONNET_FILE}" \
+    > "${DRONE_EXPECTED_CONFIG_FILE}"
+# remove last 5 lines which contain the signature
+head -n -5 "${DRONE_CONFIG_FILE}" > "${DRONE_ACTUAL_CONFIG_FILE}"
+diff "${DRONE_EXPECTED_CONFIG_FILE}" "${DRONE_ACTUAL_CONFIG_FILE}"
+
+EXIT_STATUS=$?
+if [[ "${EXIT_STATUS}" -eq 1 ]]; then
+    echo "There is a drift between ${DRONE_JSONNET_FILE} and ${DRONE_CONFIG_FILE}"
+    echo "You can fix it by running:"
+    echo "make drone"
+else
+    echo "${DRONE_CONFIG_FILE} is up to date"
+fi
+
+exit "${EXIT_STATUS}"