protoc-gen-go: import_path flag doesn't do anything

[mwitkow]

We'd like to add a go get like prefix to all of our generated protobuf packages.

The option in generator.go called PackageImportPath seems like it should do what we want:

PackageImportPath string            // Go import path of the package we're generating code for

However, that value is never used in the codebase.

The ImportPrefix, unfortunately, prefixes all imports, including the full go get paths internal to protobufs.

[mwitkow]

PR with a proposed fix ready. We checked and it seems to be doing exactly as advertised :)

[dsymonds]

What do you mean it isn't used? It's used in the defaultGoPackage method.

But if you want to control the import path on a per-input basis, that's what the M parameter is for. It populates ImportMap and has full flexibility.

[mwitkow]

Apologies, I haven't made the connection between defaultGoPackage and the written go lines, partially because it's not clear what it's meant to do.

I thought that when I specify protoc ... --go_out=plugins=grpc,import_path=mygit.com/autogen:/tmp/dest (using import_path as the way to specify PackageImportPath) , I'd get the following:

import proto "github.com/golang/protobuf/proto"

// discarding unused import google_api1 "mygit.com/autogen/google/api"
import google_protobuf1 "mygit.com/autogen/google/protobuf"
import base1 "mygit.com/autogen/base"

(where in a file generated from base/serverstatus.proto)

Instead I get:

import proto "github.com/golang/protobuf/proto"

// discarding unused import google_api1 "google/api"
import google_protobuf1 "google/protobuf"
import base1 "base"

If, I use import_prefix=mygit.com/autogen, I get:

import proto "mygit.com/autogen/github.com/golang/protobuf/proto"

// discarding unused import google_api1 "mygit.com/autogen/google/api"
import google_protobuf1 "mygit.com/autogen/google/protobuf"
import base1 "mygit.com/autogen/base"

So basically, there's no way to be able to say: prefix all the Go import paths that are an output of protoc. This is really useful when you use the go get convention for imports.
We're working around that by using import_prefix and then seding the file to remove the prefix from github.com/golang/protobuf/proto. How can we achieve this without such ugly hacks?

[dsymonds]

The import_prefix parameter is for when the whole code base is effectively vendored. If you only have a subset of packages that need some sort of prefix, use the M parameter, which permits you to specify an arbitrary mapping from proto file to import path. But maybe post-processing is simpler for you.

[mwitkow]

Currently we use import_prefix for all and sed the standard proto dependencies out.

Since we use the "single repo" GOPATH approach (with vendoring done through subtrees), it would be incredibly useful for us to not have to hack our way around postprocessing and have a flag that would add a Go import "base protobuf" prefix. I tried the M parameter, but since we have a big tree of protobufs, it quickly became a nightmare to maintain.

[drombosky]

I also have the same problem as @mwitkow-io. We currently are using protobufs with Python but are looking to make the move to Go for some of our services.

Something like #64 would fix our problem immediately. Using the mapping parameter is possible, but a large pain for both existing and new message packages.

Regarding vendoring, having this package do it's own vendoring seems counterproductive given various 3rd party vendoring tools and the GO15VENDOREXPERIMENT flag in 1.5.

[mwitkow]

@dsymonds any comment on maybe introducing a different import_path parameter that would address this usecase?

[zeroZshadow]

Im currently fighting with this issue as well, however mwitkow's PR does not seems to change anything?
protoc.exe -I . --go_out=import_path=test/:pb *.proto
One of the protofiles imports another package in the root directory, which results in import pb "."

[sean-q]

Same problem here - I would like a way to change the import_prefex for the pb.go files I am generating, but leave the "github.com/golang/protobuf/proto" import alone. import_prefix changes both, which is not what I would like.

[idevz]

I also have the same problem, any update here?

[jacovieASAPP]

Is there any resolution to this issue?

[neild]

The title of this issue is clearly incorrect--import_path sets the package name of generated files if they don't contain a go_package option. Admittedly, I don't think it's useful, since you can and should set the go_package option instead. (I'm guessing it predates go_package?)

I think the underlying problem described here was addressed by #139, which permits specifying the import path for files in the go_package option.

There are a couple additional comments here about import_prefix being too broad, which is a separate issue and I believe covered more specifically by #181. I'm going to close this in favor of that issue.