How to use my local browser and get access to the server on Circle CI with port-forwarding

This helped me to debug a failing test, that was only happening on the CircleCI Server.

How to do it?
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1. Go to Details Job Page on the Circle CI app and re-run the job as `Rerun Job with SSH`.
![image](https://user-images.githubusercontent.com/10084099/111015129-e664bb80-836c-11eb-89d4-e18887d80612.png)

2. You should be able to find an additional step called `Enable SSH`, just _**expand it**_ to see a command similar to this `ssh -p 64625 ubuntu@54.221.135.43` but with _**minor differences**_ (the port number and IP address will be different). Copy the command into your terminal.

3. _**Paste it and append this**_ `-L 3000:localhost:4000`. With this, every request happening on the port `4000` (CircleCI server) will be forwarded to my local computer in the port `3000`, so my local browser can reach the CircleCI server directly.

    `$ ssh -p 64625 ubuntu@54.221.135.43 -L 3000:localhost:4000`

4. Lastly, _**change of directory**_, go to your application folder and _**serve your app in port 4000**_.

    `$ cd my-app-directory && <command to serve your app>`
    
    In this example, I ran `yarn run dev` which runs a server on the port `4000`.

5. Go to the browser and visit the `localhost:3000`.

rogelio-alatorre
March 12, 2021