Pass pipelineArn to a stack deployed by the pipeline

[bmmin]

I have a cdk pipeline in a monorepo, and I would like to add a stage, that deploys some tooling to deal with the pipeline (e.g. notifications, etc).

I would prefer to have this stack separate, mostly becuase I dont want the pipeline update step to fail in case this stack would fail to deploy, I would rather that it fails at the stage where this should be in the pipeline.

My ops stack containing the tools, takes a pipelineArn as a parameter. How can I get the pipelineArn before building the pipeline?

I tried

pipeline.addWave("Ops").addStage(new OpsStage(this, "Ops", { pipelineArn: pipeline.pipeline.pipelineArn }));

but this fails with Pipeline not created yet during synth.

If I build the pipeline first, then I cannot add the stage any more.

How do I get around this?