Better error log when dialing without internet connection

[allisonschiang]

Old error:
2025-11-10T22:55:40.444Z ERROR client gosdk/gosdk.go:28 context deadline exceeded; context deadline exceeded; mDNS query failed to find a candidate

new error:
2025-11-11T16:13:31.449Z ERROR client gosdk/gosdk.go:28 failed to connect to robot within time limit. check network connection and try again. see http://docs.viam.com/dev/tools/common-errors/#conn-time-out for troubleshooting steps.

note: this only changes CLI and Go SDK logs, as other SDKs have their own conn logic

note2: currently no viam link system to shorten links so itll stay long

[aldenh-viam]

Same as other PRs: Would there be any significant performance improvement if we use the errors.Is pattern instead of strings.Contains?

[allisonschiang]

Same as other PRs: Would there be any significant performance improvement if we use the errors.Is pattern instead of strings.Contains?

the error returned when the user has no internet and all three connection types fail is "context deadline exceeded; context deadline exceeded; mDNS query failed to find a candidate" which all individually don't have an error type. I also believe context deadline exceeded is returned from an external package, so would have to check it coming in if its that error with strings.Contains() and then make it into a Viam error type anyways? unless there is another way to do it

[cheukt]

would prefer the change to be made where the error is getting returned, so in goutils in the dial function. There it'll be easier to use errors.Is

[allisonschiang]

would prefer the change to be made where the error is getting returned, so in goutils in the dial function. There it'll be easier to use errors.Is

connectWithLock() seems to be calling dial() once for webRTC and then once for gRPC, so not sure how to make the changes in dial() when we want both dial() attempts to have the contextDeadlineExceeded before we return "failed to connect to robot within time limit". I did make the change to use Errors.is() on dial returns though.

[cheukt]

for example, we can have https://github.com/viamrobotics/goutils/blob/0101be5c0b20620db2ee121dd37dccdcec751361/rpc/dial.go#L103 return a different error (maybe something like all connection attempts timed out) if all connection methods failed with deadline exceeded or mDNS query failed to find a candidate. Then here, we can check that the last error is all connection attempts timed out and then return this custom error. I suggest doing it this way because goutils shouldn't return errors that link specifically to viam doc sites, so something intermediate would be preferred.

As it is, I think we're only checking that one out of the possibly three bundled errors is a context deadline exceeded error, which would be incorrect

[cheukt]

talked offline - go clients makes a second dial if the first dial fails. the first dial already (unintentionally) swallows the mDNS timeout, which was why I was a bit confused. I think it makes sense to make the change here instead of a combination of both goutils and rdk, but to make sure that the err is deadline exceeded, and grpcErr comprises of both deadline exceeded and mDNS query failed to find a candidate

[allisonschiang]

ErrMDNSQuery gets exported with my matching goutils changes

[allisonschiang]

tested again and got error message: failed to connect to machine within time limit. check network connection, whether the viam-server is running, and try again. see https://docs.viam.com/dev/tools/common-errors/#conn-time-out for troubleshooting steps

[cheukt]

we should do this check before we combine the errors in L538

[cheukt]

LGTM

[allisonschiang]

LGTM

oops sorry I rerequested review