Not work with grpc v1.53.0

[erisenxu]

The latest version v3.3.1 does not work with grpc v1.53.0. When compiling, I get the following error:

../go1.18.1/pkg/mod/github.com/sercand/kuberesolver/v3@v3.1.1/builder.go:81:12: invalid operation: end == "" (mismatched types func() string and untyped string)
../go1.18.1/pkg/mod/github.com/sercand/kuberesolver/v3@v3.1.1/builder.go:82:9: cannot use target.Authority (variable of type string) as type func() string in assignment
../go1.18.1/pkg/mod/github.com/sercand/kuberesolver/v3@v3.1.1/builder.go:86:12: invalid operation: end == "" (mismatched types func() string and untyped string)
../go1.18.1/pkg/mod/github.com/sercand/kuberesolver/v3@v3.1.1/builder.go:91:23: cannot use end (variable of type func() string) as type string in argument to strings.LastIndex
../go1.18.1/pkg/mod/github.com/sercand/kuberesolver/v3@v3.1.1/builder.go:92:10: cannot use end (variable of type func() string) as type string in assignment
../go1.18.1/pkg/mod/github.com/sercand/kuberesolver/v3@v3.1.1/builder.go:97:39: cannot use end (variable of type func() string) as type string in argument to net.SplitHostPort

This is because in grpc v1.53.0, the "target.Endpoint" is a function. Can you fix it?

[dannyskoog]

See #36

[dannyskoog]

@sercand 2 weeks+ have now passed and it's blocking people. Could you please have a look at the above PR?

[mikewiacek]

See #37

Different than PR 36 as net/url can't adequately parse named ports in URLs correctly. 37 above goes to some extensive efforts to make sure all the supported resolving approaches work. If I missed one, let me know.

[wyattanderson]

Different than PR 36 as net/url can't adequately parse named ports in URLs correctly. 37 above goes to some extensive efforts to make sure all the supported resolving approaches work. If I missed one, let me know.

@mikewiacek As far as I'm aware, #36 still supports all existing supported use cases. It's not that net/url can't adequately parse named ports in URLs, it's that ports in the authority component of RFC 3986 URLs must be numeric (see RFC 3986 § 3.2.3). As of grpc/grpc-go#4817, the Go gRPC target parser uses url.Parse to parse the dial target, so a custom resolver wouldn't ever even be able to handle a URL like kubernetes://service:port because that's not a valid RFC 3986 URL and gRPC now formally requires RFC 3986 URLs for targets.

[mikewiacek]

Totally true, but if the historic behavior was to allow named ports, then maintaining backwards compatibility may be important. Especially if using an older version of grpc. But I have no pride in the fight, I just wanted it work. :-)

[sercand]

I'm really sorry for the late response. For some reason, I couldn't see the notifications for this.

#36 is merged and v4.0.0 released