build(aio): add script for updating the preview server

aio/aio-builds-setup/docs/_TOC.md

@@ -23,6 +23,10 @@
 - [Start docker container](vm-setup--start-docker-container.md)
 
 
+## Updating the docker container
+- [Update docker container](vm-setup--update-docker-container.md)
+
+
 ## Miscellaneous
 - [Debug docker container](misc--debug-docker-container.md)
 - [Integrate with CI](misc--integrate-with-ci.md)

aio/aio-builds-setup/docs/overview--scripts-and-commands.md

@@ -22,6 +22,9 @@ available:
   upload build artifacts. This is useful for CI integration. See [here](misc--integrate-with-ci.md)
   for more info.
 
+- `update-preview-server.sh`
+  Can be used for updating the docker container (and image) based on the latest changes checked out
+  from a git repository. See [here](vm-setup--update-docker-container.md) for more info.
 
 ## Commands
 The following commands are available globally from inside the docker container. They are either used

aio/aio-builds-setup/docs/vm-setup--update-docker-container.md

@@ -0,0 +1,52 @@
+# VM setup - Update docker container
+
+
+## Overview
+Assuming you have cloned the repository containing the preview server code (as described
+[here](vm-setup--create-docker-image.md)), you can use the `update-preview-server.sh` script on the
+VM host to update the preview server based on changes in the source code.
+
+The script will pull the latest changes from the origin's master branch and examine if there have
+been any changes in files inside the preview server source code directory (see below). If there are,
+it will create a new image and verify that is works as expected. Finally, it will stop and remove
+the old docker container and image, create and new container based on the new image and start it.
+
+The script assumes that the preview server source code is in the repository's
+`aio/aio-builds-setup/` directory and expects the following inputs:
+
+- **$1**: `HOST_REPO_DIR`
+- **$2**: `HOST_LOCALCERTS_DIR`
+- **$3**: `HOST_SECRETS_DIR`
+- **$4**: `HOST_BUILDS_DIR`
+- **$5**: `HOST_LOGS_DIR`
+
+See [here](vm-setup--create-host-dirs-and-files.md) for more info on what each input directory is
+used for.
+
+**Note 1:** The script has to execute docker commands with `sudo`.
+
+**Note 2:** Make sure the user that executes the script has access to update the repository
+
+
+## Run the script manually
+You may choose to manually run the script, when necessary. Example:
+
+```
+update-preview-server.sh \
+    /path/to/repo \
+    /path/to/localcerts \
+    /path/to/secrets \
+    /path/to/builds \
+    /path/to/logs
+```
+
+
+## Run the script automatically
+You may choose to automatically trigger the script, e.g. using a cronjob. For example, the following
+cronjob entry would run the script every hour and update the preview server (assuming the user has
+the necessary permissions):
+
+```
+# Periodically check for changes and update the preview server (if necessary)
+*/30 *  * * *   /path/to/update-preview-server.sh /path/to/repo /path/to/localcerts /path/to/secrets /path/to/builds /path/to/logs
+```

aio/aio-builds-setup/scripts/update-preview-server.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+
+set -eux -o pipefail
+exec 3>&1
+
+# Input
+readonly HOST_REPO_DIR=$1
+readonly HOST_LOCALCERTS_DIR=$2
+readonly HOST_SECRETS_DIR=$3
+readonly HOST_BUILDS_DIR=$4
+readonly HOST_LOGS_DIR=$5
+
+# Constants
+readonly PROVISIONAL_IMAGE_NAME=aio-builds:provisional
+readonly LATEST_IMAGE_NAME=aio-builds:latest
+readonly CONTAINER_NAME=aio
+
+# Run
+(
+  echo "[`date`] - Updating the preview server..."
+
+  cd "$HOST_REPO_DIR"
+
+  readonly lastDeployedCommit=$(git rev-parse HEAD)
+  echo "Currently at commit $lastDeployedCommit."
+
+  # Pull latest master from origin.
+  git pull origin master
+
+  # Do not update the server unless files inside `aio-builds-setup/` have changed.
+  readonly relevantChangedFilesCount=$(git diff --name-only $lastDeployedCommit...HEAD | grep -P "^aio/aio-builds-setup/" | wc -l)
+  if [[ $relevantChangedFilesCount -eq 0 ]]; then
+    echo "Skipping update because no relevant files have been touched."
+    exit 0
+  fi
+
+  # Create and verify a new docker image.
+  sudo docker rmi "$PROVISIONAL_IMAGE_NAME" || true
+  aio/aio-builds-setup/scripts/create-image.sh "$PROVISIONAL_IMAGE_NAME"
+  readonly imageVerified=$(sudo docker run --dns 127.0.0.1 --rm --volume $HOST_SECRETS_DIR:/aio-secrets:ro "$PROVISIONAL_IMAGE_NAME" /bin/bash -c "aio-init && aio-health-check && aio-verify-setup" > /dev/fd/3 && echo "true" || echo "false")
+
+  if [[ "$imageVerified" != "true" ]]; then
+    echo "Failed to verify new docker image. Aborting update!"
+    exit 1
+  fi
+
+  # Remove the old container and replace the docker image.
+  sudo docker stop "$CONTAINER_NAME" || true
+  sudo docker rm "$CONTAINER_NAME" || true
+  sudo docker rmi "$LATEST_IMAGE_NAME" || true
+  sudo docker tag "$PROVISIONAL_IMAGE_NAME" "$LATEST_IMAGE_NAME"
+  sudo docker rmi "$PROVISIONAL_IMAGE_NAME"
+
+  # Create and start a docker container based on the new image.
+  sudo docker run \
+      --detach \
+      --dns 127.0.0.1 \
+      --name "$CONTAINER_NAME" \
+      --publish 80:80 \
+      --publish 443:443 \
+      --restart unless-stopped \
+      --volume $HOST_LOCALCERTS_DIR:/etc/ssl/localcerts:ro \
+      --volume $HOST_SECRETS_DIR:/aio-secrets:ro \
+      --volume $HOST_BUILDS_DIR:/var/www/aio-builds \
+      --volume $HOST_LOGS_DIR:/var/log/aio \
+      "$LATEST_IMAGE_NAME"
+
+  echo "The new docker image has been successfully deployed."
+)