Add published version/tag check to skip docker builds

.drone.yml

@@ -7,11 +7,11 @@ steps:
 - name: build
   image: alpine
   commands:
-    - apk update && apk add bash grep sed curl unzip
+    - apk update && apk add bash grep sed curl unzip jq
     - chmod +x ./build.sh
     - ./build.sh
 
-- name: docker  
+- name: docker
   image: plugins/docker
   settings:
     repo: fbrinker/tileboard
@@ -19,7 +19,7 @@ steps:
       from_secret: docker_username
     password:
       from_secret: docker_password
-      
+
 trigger:
   branch:
   - master

build.sh

@@ -10,20 +10,35 @@ getVersionFromLatestRelease() {
 }
 
 downloadLatestRelease() {
-    URL=`curl -s "https://api.github.com/repos/resoai/TileBoard/releases/latest" \
+    url=`curl -s "https://api.github.com/repos/resoai/TileBoard/releases/latest" \
         | grep "browser_download_url" \
         | cut -d '"' -f 4`
-    echo "Url: $URL"
+    echo "Url: $url"
     
-    curl -sL -o $1 ${URL}
+    curl -sL -o $1 ${url}
 }
 
-LATEST=`getVersionFromLatestRelease`
-SEMVER=( ${LATEST//./ } )
+getLatestPublishedTag() {
+    latest_tag=`curl -s "https://hub.docker.com/v2/repositories/fbrinker/tileboard/tags?page_size=1" \
+        | jq -r ".results[0].name"`
 
+    echo "$latest_tag"
+}
+
+LATEST_RELEASE=`getVersionFromLatestRelease`
+LATEST_TAG=`getLatestPublishedTag`
+
+if [ "$LATEST_RELEASE" = "$LATEST_TAG" ]; then
+    echo "Nothing to do. Versions already match."
+    echo "Release: $LATEST_RELEASE"
+    echo "Tag: $LATEST_TAG"
+    exit 78 # drone.io exit code to stop but success the pipeline
+fi
+
+SEMVER=( ${LATEST_RELEASE//./ } )
 MAJOR=${SEMVER[0]}
 MINOR=${SEMVER[0]}.${SEMVER[1]}
-PATCH=$LATEST
+PATCH=$LATEST_RELEASE
 
 echo "latest,$MAJOR,$MINOR,$PATCH" > .tags