Can I achieve Azure function chaining with Durable Functions located in different resource groups & consumption plans? OR do the functions have to exist in the same resource group/service plan?
If this is not possible, then apart from using service bus, how can functions communicate with each other across different services?
We only support chaining durable functions from within a single function app. This is a technical limitation imposed by the current design of the underlying Azure Storage provider.
However, you could work around this in various ways depending on your needs. For example an orchestration in function app A could send a queue message that triggers a queue-trigger function in function app B which internally starts another orchestration or raises an event to an existing orchestration using the Instance Management APIs.
Durable Function orchestrations also support the async HTTP model, which means that an orchestration in function app A could use HTTP to start an orchestration in function app B, then poll the status endpoint it gets back to get the response when it's available (more info in the HTTP API topic).
But can you comment on why you want to have communication across different function apps? We've received this request before and having more data might help us implement a solution sooner. :)
