Add offline docker example for air gapped networks (#160)

This adds an example of how to use heartbeat / synthetics in an air
gapped network, where our calls to NPM won't work. Users will have to
pre-bake a container on a machine with internet access and ship that
behind their firewall.

Dockerfile

@@ -15,12 +15,15 @@ ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /tini
 RUN chmod +x /tini
 ENTRYPOINT ["/tini", "--", "/usr/local/bin/docker-entrypoint"]
 
+ENV SUITES_DIR=/usr/share/heartbeat/suites
+
 # or docker run your-image /your/program ...
 RUN echo /usr/share/heartbeat/.node \\
       /usr/share/heartbeat/.npm \\
       /usr/share/heartbeat/.cache \\
       /usr/share/heartbeat/.config \\
-      /opt/elastic-synthetics | xargs -IDIR sh -c "mkdir DIR && chown -R heartbeat DIR"
+      $SUITES_DIR \\
+      /opt/elastic-synthetics | xargs -IDIR sh -c "mkdir DIR && chown -R heartbeat:heartbeat DIR"
 ENV NODE_PATH=/usr/share/heartbeat/.node
 USER heartbeat
 RUN  cd /usr/share/heartbeat/.node \\

examples/docker/run-build-local.sh

@@ -4,4 +4,4 @@
 pushd ../../
 ./build-docker.sh $1
 popd
-./run.sh heartbeat-synthetics-local $@
+./run.sh heartbeat-synthetics-local "${@:2}"

examples/docker/run.sh

@@ -20,13 +20,15 @@ else
 	IMAGE=$VERSION
 fi
 
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+
 echo "Using image '$IMAGE' with extra args: $HEARTBEAT_ARGS"
 docker run \
   --rm \
   --name=heartbeat \
   --user=heartbeat \
   --net=host \
-  --security-opt seccomp=seccomp_profile.json \
+  --security-opt seccomp=$SCRIPT_DIR/seccomp_profile.json \
   --volume="$(pwd)/heartbeat.docker.yml:/usr/share/heartbeat/heartbeat.yml:ro" \
   --volume="$(pwd)/../../:/opt/elastic-synthetics:rw" \
   $IMAGE \

examples/todos/Dockerfile

@@ -0,0 +1,30 @@
+# This Dockerfile illustrates the usage of synthetics in an air gapped environment, where 
+# public internet access is not available. In this situation you'll want to create
+# a custom image using our official docker image as a base.
+
+# Use our synthetics image as a base.
+ARG STACK_VERSION=latest
+FROM docker.elastic.co/experimental/synthetics:${STACK_VERSION}-synthetics
+# Use the line below if you're using a custom base image, usually only for
+# developers
+#FROM heartbeat-synthetics-local
+
+# This flag variable will prevent heartbeat from running `npm i` or
+# similar commands that depend on an internet connection.
+# We'll have to do that work now, when we bake the image.
+ENV ELASTIC_SYNTHETICS_OFFLINE=true
+
+# Copy our heartbeat config directly to the image.
+# This could be done as a shared mount instead, but if we're
+# baking an image anyway, this may be something that may be easier
+# to do in this manner.
+COPY heartbeat.docker.yml /usr/share/heartbeat/heartbeat.yml
+
+RUN mkdir -p $SUITES_DIR/todos
+# Copy your custom synthetics tests into a folder on the image
+COPY . $SUITES_DIR/todos/
+
+# Install NPM deps locally on this image
+# Please note that it's important to run both `npm install` AND `npm install playwright`
+# for more see this issue: https://github.com/microsoft/playwright/issues/3712
+RUN cd $SUITES_DIR/todos && npm install

examples/todos/build-offline-dockerfile.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+# This demonstrates building and tagging a custom offline docker heartbeat image with synthetics
+# with all dependencies pre-bundled.
+
+# You'll want to run this in an environment with internet access so that NPM deps can be installed,
+# then, take the resultant image and transfer that to your air gapped network.
+docker build --build-arg STACK_VERSION=7.10.0 -t my-custom-heartbeat .

examples/todos/heartbeat.docker.yml

@@ -0,0 +1,12 @@
+---
+seccomp.enabled: false
+heartbeat.config.monitors:
+  path: "${path.config}/monitors.d/*.yml"
+  reload.enabled: false
+  reload.period: 5s
+
+heartbeat.synthetic_suites:
+- name: Todos
+  # SUITES_DIR is an environment var provided by the docker container
+  path: "${SUITES_DIR}/todos"
+  schedule: "@every 1m"