client: fix FailOnNonTempDialError and add a test for it

[virtuald]

• Fixes FailOnNonTempDialError doesn't fail #2266

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[virtuald]

Added CLA.

[dfawley]

Looks great, thanks for putting this fix together. One minor comment on the test, otherwise 👍 👍

[dfawley]

Please make this timeout eventually so the test won't hang forever if it breaks. E.g.

ctx := context.WithTimeout(context.Background(), 10*time.Second)

[virtuald]

Why don't any of the other tests do that then?

[dfawley]

🤷‍♂️ 😞

I'm fixing the ones I see when I run into them.

[virtuald]

Also, thinking about it, should a note be added to the documentation that FailOnNonTempDialError is only useful if WithBlock is also used? It's not immediately clear to me that it does anything if not using WithBlock...

[dfawley]

Also, thinking about it, should a note be added to the documentation that FailOnNonTempDialError is only useful if WithBlock is also used? It's not immediately clear to me that it does anything if not using WithBlock...

That would be great, thanks.

The whole idea of a blocking Dial is a bit unusual for the gRPC model, where a ClientConn is actually a long-lived pool of connections that may be unavailable at times. The initial connection attempt is only interesting in that if it fails, it's possible your configuration was incorrect, vs. transient network/unavailability problems.
Note that in all other languages, gRPC does not attempt to connect until the first RPC is dispatched, and the initial connection is not treated specially.

[virtuald]

Added documentation note also.

[dfawley]

Thanks!