entrypoint: Launch our entrypoint via tini

Even single process containers (which this one is actually not) should
have an init system. However most init systems are too big and complex
for containerization purposes. [Dumb-init][0] (and tini init) address
this problem _specifically_ for Docker containers.

See the [dumb-init][0] documentation for more details.

[0]: https://github.com/Yelp/dumb-init

Signed-off-by: Olliver Schinagl <[email protected]>

Author: oliv3r

Dockerfile-alpine-slim.template

@@ -99,6 +99,9 @@ RUN set -x \
 # forward request and error logs to docker log collector
     && ln -sf /dev/stdout /var/log/nginx/access.log \
     && ln -sf /dev/stderr /var/log/nginx/error.log \
+# Ensure we can run our entrypoint and make it debian compatible
+    && apk add --no-cache tini \
+    && ln -s /sbin/tini /usr/bin/tini \
 # create a docker-entrypoint.d directory
     && mkdir /docker-entrypoint.d
 

Dockerfile-alpine.template

@@ -75,4 +75,7 @@ RUN set -x \
     && if [ -n "/etc/apk/keys/abuild-key.rsa.pub" ]; then rm -f /etc/apk/keys/abuild-key.rsa.pub; fi \
     && if [ -n "/etc/apk/keys/nginx_signing.rsa.pub" ]; then rm -f /etc/apk/keys/nginx_signing.rsa.pub; fi \
 # Bring in curl and ca-certificates to make registering on DNS SD easier
-    && apk add --no-cache curl ca-certificates
+    && apk add --no-cache curl ca-certificates \
+# Ensure we can run our entrypoint and do it compatible with alpine
+    && apk add --no-cache tini \
+    && ln -s /sbin/tini /usr/bin/tini

Dockerfile-debian.template

@@ -82,6 +82,8 @@ RUN set -x \
                         $nginxPackages \
                         gettext-base \
                         curl \
+                        tini \
+    && ln -s /usr/bin/tini /sbin/tini \
     && apt-get remove --purge --auto-remove -y && rm -rf /var/lib/apt/lists/* /etc/apt/sources.list.d/nginx.list \
     \
 # if we have leftovers from building, let's purge them (including extra, unnecessary build deps)

entrypoint/docker-entrypoint.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/sbin/init /bin/sh
 # vim:sw=4:ts=4:et
 
 set -e