Allow changing port via Environment Variables

[pnutmath]

Currently, the application only allows changing the port number by passing a command-line parameter when launching the application. However, some users may not have access to this parameter switch, and as a result, they are unable to change the port number.

To make the application more flexible and accessible, I propose adding support for changing the port number via environment variables. This will enable users to specify the port number without having to pass command-line parameters.

The implementation of this feature will involve adding a new configuration option that checks for the value of an environment variable, and if present, uses it as the port number. If the environment variable is not set, the application will default to the current behavior of using the command-line parameter.

We believe this change will improve the usability and accessibility of the application for all users.

Suggested change:

Just setting default value PORT to api-port-from-env should work

fs.String("api-port-from-env", "PORT", "Set the environment variable with the port on which the API should listen - override the default port")		

gotenberg/pkg/modules/api/api.go

Line 165 in 888f3fe

fs.String("api-port-from-env", "", "Set the environment variable with the port on which the API should listen - override the default port")

[gulien]

Hello @pnutmath,

I'm not against the idea, but do you have an exemple of a provider / infrastructure that does not allow the setting of a command flag? 😄

[pnutmath]

Our internal layer on top of Kubernetes does not support args and does not allow changing the targetPort at the service level as of now. Change request is also taking time than expected.

It would be helpful to support environment variables for port selection using the standard PORT variable. This would definitely improve usability.