How to deploy Synchronizer Docker container in Heroku?

Question

How to deploy Synchronizer Docker Container in heroku environment?

Answer

Follow the steps below to deploy Synchronizer container in heroku

1. Download the Synchronizer source code from the git repository

2. Unzip the source code in a new folder (for example: mysync), then open terminal and cd to the folder. Run the following command:

heroku create

This will create the heroku application, you will see a response similar to this:

Creating app... done, ⬢ secret-anchorage-16496
https://secret-anchorage-16496.herokuapp.com/ | https://git.heroku.com/secret-anchorage-16496.git

3. Next step is to set the image as container, then add the go language pack

heroku stack:set container
heroku buildpacks:set heroku/go

4. Open the existing Dockerfile and replace the last line

ENTRYPOINT ["sh", "./entrypoint.sh"]

with

CMD ["sh", "./entrypoint.sh"]

This is due to heroku supporting  CMD only.

5. Create new file named heroku.yml with the content below:

build:
 docker:
 web: Dockerfile
 worker:
 dockerfile: Dockerfile

6. Create new file name Procfile with the content below:

worker: sh entrypoint.sh

7. To add the Docker environment variables, open the heroku.com page and click on your new app, click on "Settings" tab and add the environment variables below:

SPLIT_SYNC_API_KEY
SPLIT_SYNC_REDIS_HOST
SPLIT_SYNC_REDIS_PORT
SPLIT_SYNC_REDIS_DB
SPLIT_SYNC_REDIS_PASS

8. To expose the Admin dashboard, we need to map it to the $PORT environment variable set by heroku, and overwrite the existing port used by synchronizer. Open the entrypoint.sh file and replace this line at the end:

exec split-sync ${PARAMETERS}

With:

exec split-sync ${PARAMETERS} -sync-admin-port $PORT

9. Run the git commands below to push the image:

git init
git add .
git commit
git push heroku master

10. Once the push is finished successfully, run the command below to verify if the synchronizer is running successfully.

heroku logs

You should see content like below:

2019-09-11T19:53:06.954882+00:00 app[worker.1]: __      ____        _ _ _
2019-09-11T19:53:06.954887+00:00 app[worker.1]: / /__   / ___| _ __ | (_) |_
2019-09-11T19:53:06.954890+00:00 app[worker.1]: / / \ \  \___ \| '_ \| | | __|
2019-09-11T19:53:06.954891+00:00 app[worker.1]: \ \  \ \  ___) | |_) | | | |_
2019-09-11T19:53:06.954893+00:00 app[worker.1]: \_\ / / |____/| .__/|_|_|\__|
2019-09-11T19:53:06.954895+00:00 app[worker.1]: /_/        |_|
2019-09-11T19:53:06.954897+00:00 app[worker.1]: 
2019-09-11T19:53:06.954899+00:00 app[worker.1]: 
2019-09-11T19:53:06.954922+00:00 app[worker.1]: 
2019-09-11T19:53:06.954924+00:00 app[worker.1]: Split Synchronizer - Version: 2.5.1 (2178c61)
2019-09-11T19:53:06.955154+00:00 app[worker.1]: Log file: /tmp/split-agent.log

 11. You can also view the admin dashboard from the URL:

https://[heroku app name].herokuapp.com/admin/dashboard

Note:

When using Synchronizer as a proxy service, we have to assign the listener port to the $PORT environment variable created by heroku, which will be mapped to port 80 in heroku router. Follow the instructions below:

a- Open entrypoint.sh file and scroll to the end, replace the line:

exec split-sync ${PARAMETERS}

With:

exec split-sync ${PARAMETERS} -proxy-port $PORT

b- Deploy using web to open port 80 in heroku, change content of file Procfile with the content below:

web: sh entrypoint.sh

c- Make sure to add the following environment variables in heroku UI with:

SPLIT_SYNC_PROXY (value: on)
SPLIT_SYNC_PROXY_SDK_APIKEYS (value: any custom api key)

c- Push the new image using git:

git add .
git commit
git push heroku master

 d- On the SDK side, (for example Java SDK) use the heroku app URL for the endpoint in the config object:

SplitClientConfig config = SplitClientConfig.builder()
    .setBlockUntilReadyTimeout(5000)
    .endpoint("http://[heroku app name].herokuapp.com", "http://[heroku app name].herokuapp.com")
    .build();
try {
      splitFactory = SplitFactoryBuilder.build("custom api key", config);
      client = this.splitFactory.client();
      client.blockUntilReady();
} catch (Exception e) {
   System.out.print("Exception: "+e.getMessage());
}

 Since the default heroku deployment allows mapping only one port, which is used for the proxy listener service, the admin dashboard page will be unaccessible.