Support for GITLAB_RUNNER_{UID,GID} build args added

Dockerfile

@@ -8,6 +8,14 @@ MAINTAINER Michał "rysiek" Woźniak <rysiek@occrp.org>
 # environment
 ENV DEBIAN_FRONTEND=noninteractive
 
+# uid and gid of the gitlab-runner user
+ARG GITLAB_RUNNER_UID=999
+ARG GITLAB_RUNNER_GID=999
+
+# and let's modify the group and the user
+RUN groupmod --gid ${GITLAB_RUNNER_GID} gitlab-runner \
+    && usermod --uid "${GITLAB_RUNNER_UID}" gitlab-runner
+
 # adding repository keys
 ARG ADD_REPOSITORY_KEYS=
 RUN if [ "$ADD_REPOSITORY_KEYS" != "" ]; then \

entrypoint

+#!/bin/bash
+
+#
+# almost exact copy of:
+# https://gitlab.com/gitlab-org/gitlab-runner/blob/master/dockerfiles/ubuntu/entrypoint
+# (original is MIT-licensed)
+#
+# we need our copy because we want to run gitlab-runner as a specific user:group
+#
+
+# gitlab-runner data directory
+DATA_DIR="/etc/gitlab-runner"
+CONFIG_FILE=${CONFIG_FILE:-$DATA_DIR/config.toml}
+# custom certificate authority path
+CA_CERTIFICATES_PATH=${CA_CERTIFICATES_PATH:-$DATA_DIR/certs/ca.crt}
+LOCAL_CA_PATH="/usr/local/share/ca-certificates/ca.crt"
+
+update_ca() {
+  echo "Updating CA certificates..."
+  cp "${CA_CERTIFICATES_PATH}" "${LOCAL_CA_PATH}"
+  update-ca-certificates --fresh >/dev/null
+}
+
+if [ -f "${CA_CERTIFICATES_PATH}" ]; then
+  # update the ca if the custom ca is different than the current
+  cmp --silent "${CA_CERTIFICATES_PATH}" "${LOCAL_CA_PATH}" || update_ca
+fi
+
+# launch gitlab-runner passing all arguments
+exec su -p -c "env PATH=\"$PATH\" gitlab-runner $*" gitlab-runner