CI: create a function to check if an image can be pulled

1 files changed, 26 insertions, 13 deletions

diff --git a/scripts/check_dockerfiles.sh b/scripts/check_dockerfiles.sh
index a0294b1..f2b8512 100755
--- a/scripts/check_dockerfiles.sh
+++ b/scripts/check_dockerfiles.sh
@@ -32,6 +32,31 @@ get_build() {
     fi
 }
 
+can_pull() {
+    local image="${1:?"can_pull: argument 1 'image' is unset"}"
+
+    local master_commit
+    if master_commit="$(
+            get_build "refs/heads/master" \
+            | jq -re '.value[0].sourceVersion'
+        )" \
+        && git diff --quiet "${master_commit}" -- "${@:2}"
+    then
+        printf \
+            '%s\n' \
+            "Can pull ${image} image from Docker Hub; no changes since master."
+
+        printf '%s\n' "##vso[task.setvariable variable=${image^^}_PULL]True"
+    else
+        printf \
+            '%s\n' \
+            "Cannot pull ${image} image from Docker Hub due to detected " \
+            "changes; the ${image} image will be built."
+
+        return 1
+    fi
+}
+
 # Get the previous commit
 if [[ "${BUILD_REASON}" = "PullRequest" ]]; then
     if ! prev_commit="$(
@@ -80,17 +105,5 @@ else
         "the venv image will be built."
 
     # Though base image hasn't changed, it's still needed to build the venv.
-    if master_commit="$(
-            get_build "refs/heads/master" \
-            | jq -re '.value[0].sourceVersion'
-        )" \
-        && git diff --quiet "${master_commit}" -- docker/base.Dockerfile
-    then
-        echo "Can pull base image from Docker Hub; no changes since master."
-        echo "##vso[task.setvariable variable=BASE_PULL]True"
-    else
-        echo \
-            "Cannot pull base image from Docker Hub due to detected changes;" \
-            "the base image will be built."
-    fi
+    can_pull base docker/base.Dockerfile
 fi