Is `config.sessionStartupCustom` possible on Workbench?

[SamEdwardes]

The Workbench Helm chart currently has a config.startupCustom key. For example:

helm/examples/auto-scaling/rstudio-workbench/values.yaml

Lines 148 to 162 in c48d94f

	startupCustom:
	create-users-ongoing.sh: |
	#!/bin/bash
	for user in users.txt; do
	USERNAME=$(cat users.txt | grep -v '^\s*#'| cut -d: -f1)
	USERID=$(cat users.txt | grep -v '^\s*#'| cut -d: -f2)
	echo "$USERNAME"
	PASSWORD=$(cat users.txt | grep -v '^\s*#'| cut -d: -f3)
	useradd -u $USERID -m -s /bin/bash -N $USERNAME
	echo "$USERNAME:$PASSWORD" | sudo chpasswd
	done;
	echo 'sleeping forever'
	while :; do read; done

Would it be possible to have scripts that run when a IDE session starts? The motivation for this is a want to create a symlink on the session container before the IDE starts. For example:

config:
  session:
    repos.conf:
      RSPM: https://packagemanager.rstudio.com/cran/__linux__/jammy/latest
      CRAN: https://packagemanager.rstudio.com/cran/__linux__/jammy/latest
  sessionStartupCustom:
    symlink-odbc.sh: |
      #!/bin/bash
      ln -s /mnt/session-secret/odbc.ini /ect/odbc.ini
  sessionSecret:
    odbc.ini: |
      [ProjectAbcDatabase]
      Database=project_abc
      Driver=PostgreSQL
      Password=password
      Port=5432
      Servername=database-postgresql
      UserName=posit_team

Or maybe there is a way to already do this?

[colearendt]

I think for proper function, this would need to be built into the product. We have this doc here, but it is really gross and not something we would want to standardize:

https://support.posit.co/hc/en-us/articles/360059743753-Customizing-the-Entrypoint-with-RStudio-Workbench-RStudio-Server-Pro-Job-Launcher-and-Kubernetes

But maybe something like a /docker-entrypoint.d/ directory for session images that is respected and used by the rserver-launcher process could help with situations like this... although it would not help "launcher jobs," which do not run a parent binary. This is kinda the convention being set up here: rstudio/rstudio-docker-products#337

[SamEdwardes]

Thanks for the input Cole. How does it work for config.startupCustom? Is that baked in at the product level? Could we just replicate the same logic to have a config.sessionStartupCustom?