Asynchronous deployment of helm releases

[turkenh]

What problem are you facing?

Currently, install and upgrade calls using helm go client is blocking which means, reconcile loop is being blocked until deployment is done. Since we don't set wait (related), this is fine if chart does not contain hooks. However, with hooks we encounter problems like this.

How could Crossplane help solve your problem?

We need to make this action asynchronous somehow.

[turkenh]

Related: helm/helm#5891

[jbw976]

Are you still working on this @turkenh, or would it be available for someone else to take on?

[turkenh]

@jbw976 not really. Just unassigned from myself and available for anyone interested.

[turkenh]

For posterity, I believe this could be implemented by following a similar approach used in Terrajet: https://github.com/crossplane/terrajet/blob/6142eefbcf5b4e6490a4a39f8ceffa8810911d5f/pkg/terraform/workspace.go#L106

We might even consider to have a cli execution library (sync/async) as a reusable piece of code, e.g. in crossplane-runtime. Not sure if this worths the amount of work required though.