Handling a dollar sign in a username for deploying Azure Web App via FTP on GitLab CI
As usual the easiest things take a lot of time – or luck – to debug. Last few days I was trying to deploy this blog to a Azure Web App from GitLab’s CI via good old FTP. The problem is the FTP username on Web App is always in the form of web_app_name\$web_app_name. So the backslash and dollar cannot be avoided i.e. by regenerating publishing credentials. And I don’t have to explain to you these characters are often, in various environments, handled specifically.
tl;dr;
Long story short, if you have dollar sign in a GitLab CI variable, you have to escape it by another $. In my example it would be web_app_name\$$web_app_name.
Full story
For FTP deployment I’m using lftp and a trivial bash script. Putting the username and password into Secret variables, to be able to have the repository public. Running the build I was unable to login. Some debugging later I found the username was not correctly passed to the FTP server. At that point I somewhat convinced myself the lftp is doing something wrong handling the credentials and I spent days trying to avoid it (various quotings, different commands, …).
Luckily I got a nudge in a correct direction. What if the lftp is innocent and GitLab CI is doing something wrong? Quick echo test confirmed it. The dollar sign (and whatever follows) is expanded on GitLab CI before (as if it was a regular variable) passing it to the script. Quoting it with another $ solves it right away.
I was hunting in a completely wrong forest!
