Add support for auto tag

[rverma-nikiai]

Drone docker plugin has support for auto tag, may be we can borrow some code from there..

[andrewmclagan]

At present this plugin is a simple shell script. Would need to migrate to Go or another language to add support for this.

[andrewmclagan]

Thinking this through, we may be able to use the Kaniko binary as a replacement for the docker binary and build then use the base drone-docker plugin. Simply replacing the docker binary with Kaniko binary? Or perhaps importing the Kaniko go package?

--- thoughts?

[bonifaido]

I don't think that the docker binary is simply replaceable with the kaniko binary since the command line arguments differ. Importing it as a package is another thing, let me have a look on the auto-tag feature, I'm not that familiar with that one.

[annProg]

possible solution

diff --git a/plugin.sh b/tmp/plugin.sh
index 57c2e34..c650ccd 100755
--- a/plugin.sh
+++ b/tmp/plugin.sh
@@ -50,6 +50,30 @@ if [ -n "${PLUGIN_BUILD_ARGS_FROM_ENV:-}" ]; then
     BUILD_ARGS_FROM_ENV=$(echo "${PLUGIN_BUILD_ARGS_FROM_ENV}" | tr ',' '\n' | while read build_arg; do echo "--build-arg ${build_arg}=$(eval "echo \$$build_arg")"; done)
 fi
 
+# auto_tag, if set auto_tag: true, auto generate .tags file
+if [[ "${PLUGIN_AUTO_TAG:-}" == "true" ]]; then
+    # only support va.b.c and a.b.c
+    TAG=$(echo "${DRONE_TAG}" |sed 's/^v//g')
+    l=$(echo "${TAG}" |tr '.' '\n' |wc -l)
+    echo ${TAG} |grep -E "[a-z-]" &>/dev/null && r=0 || r=1
+
+       if [ ! -n "${TAG:-}" ];then
+               echo "latest" > .tags
+       elif [ ${r} -eq 0 -o ${l} -gt 3 ];then
+        echo "v${TAG},latest" > .tags
+    else
+        major=$(echo "${TAG}" |awk -F'.' '{print $1}')
+        minor=$(echo "${TAG}" |awk -F'.' '{print $2}')
+        release=$(echo "${TAG}" |awk -F'.' '{print $3}')
+    
+        major=${major:-0}
+        minor=${minor:-0}
+        release=${release:-0}
+    
+        echo "v${major},v${major}.${minor},v${major}.${minor}.${release},latest" > .tags
+    fi  
+fi
+
 if [ -n "${PLUGIN_TAGS:-}" ]; then
     DESTINATIONS=$(echo "${PLUGIN_TAGS}" | tr ',' '\n' | while read tag; do echo "--destination=${REGISTRY}/${PLUGIN_REPO}:${tag} "; done)
 elif [ -f .tags ]; then

[bonifaido]

Looks promising! Would you mind contributing this in form of a PR @annProg ? 🙂