Fix date handling for ISO8601 dates

check-master-for-changes.sh

@@ -1,13 +1,23 @@
 #!/usr/bin/env bash
 
-commitdate=$(curl -sL "https://api.github.com/repos/resoai/TileBoard/commits/master" | jq -r ".commit.author.date")
-commitdays=$(( ( $(date --utc +%s) - $(date --utc -d $commitdate +%s) ) / 86400 ))
-echo "Last commit was $commitdays days ago."
+docker_tag_exists() {
+    repo="${1-fbrinker/tileboard}"
+    tag="${2-nightly}"
+    curl --silent -f -lSL "https://hub.docker.com/v2/repositories/$repo/tags/$tag" > /dev/null 2>&1
+}
 
-if [ $commitdays -lt 2 ] ; then
-  echo "There ARE recent changes in the repository."
+commitdate=$(curl -sL "https://api.github.com/repos/resoai/TileBoard/commits/master" | jq -r ".commit.author.date" | sed 's/T/ /; s/Z//')
+commitdays=$(( ( $(date --utc +%s) - $(date --utc -d "$commitdate" +%s) ) / 86400 ))
+echo "Last commit was $commitdate and is $commitdays days ago."
+
+if [ $commitdays -lt 2 ]; then
+  echo "Found recent commits in the repository."
+  echo "Continuing with pipeline..."
+elif [ !docker_tag_exists ]; then
+  echo "Missing an nightly build."
+  echo "Continuing with pipeline..."
 else
-  echo "There are NO recent changes in the repository."
+  echo "No recent commits found."
   echo "Aborting pipeline."
   exit 78 # drone.io exit code to stop but success the pipeline
 fi