add docker build script from OpenGrok/docker repo

Author: Vladimir Kotal

dev/docker.sh

@@ -0,0 +1,51 @@
+#!/bin/bash
+
+#
+# Build and push new image to Docker hub.
+#
+# Uses the following Travis secure variables:
+#  - DOCKER_USERNAME
+#  - DOCKER_PASSWORD
+#  - GITHUB_TOKEN
+#
+# These are set via https://travis-ci.com/OpenGrok/docker/settings
+#
+
+set -x
+set -e
+
+# Travis can only work on master since it needs encrypted variables.
+if [ "${TRAVIS_PULL_REQUEST}" != "false" ]; then
+	exit 0
+fi
+
+JSON_OUT="ver.out"
+
+#
+# Get the latest OpenGrok version string. Use authenticated request to avoid
+# rate limiting induced errors.
+#
+curl -sS -o "$JSON_OUT" \
+    -H "Authorization: token $GITHUB_TOKEN" \
+    https://api.github.com/repos/oracle/opengrok/releases/latest
+cat "$JSON_OUT"
+VERSION=`jq -er .tag_name ver.out`
+echo "Latest OpenGrok tag: $VERSION"
+
+# Embed the tarball URL into the Dockerfile.
+tarball=`jq -er '.assets[]|select(.name|test("opengrok-.*tar.gz"))|.browser_download_url' "$JSON_OUT"`
+echo "Tarball URL: $tarball"
+sed "s%OPENGROK_DOWNLOAD_LINK%$tarball%" Dockerfile.tmpl > Dockerfile
+
+# Build and run the image in container.
+docker build -t opengrok/docker:$VERSION -t opengrok/docker:latest .
+docker run -d opengrok/docker
+docker ps -a
+
+# Publish the image to Docker hub.
+if [ -n "$DOCKER_PASSWORD" -a -n "$DOCKER_USERNAME" -a -n "$VERSION" ]; then
+	echo "Pushing image for version $VERSION"
+	echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin
+	docker push opengrok/docker:$VERSION
+	docker push opengrok/docker:latest
+fi