Use envsubst with yq variable

[robross0606]

I have a situation where I need to use an environment variable if not blank, or default to using a parsed yq variable if the environment variable is not set. I looked at strenv, env and envsubst. I would use the // alternative operator, but the environment variable would probably be blank and not null. envsubst looks like it might fit the bill other than that I'm not sure of the syntax for referencing the yq variable as the default.

Where GITOPS_BRANCH_OVERRIDE is an environment variable and item is a yq variable, would something like this work?

yq --null-input '"the ${GITOPS_BRANCH_OVERRIDE:-$$item.TRIGGER_CONTEXT} meows" | envsubst'