Goal of this repo is to showcase:
- How to use the
bufCLI to generate Twirp code. - Use the
--templateoption to workaround certain plugins, such as Twirp, that generate all code to the same package and expect the same package name (which isn't always desired).
If you ran into "error:files have conflicting go_package settings", you're in the right place.
The following buf command generates Go and Twirp code from the buf.gen.yaml template. Bonus, all plugins are hosted on buf.build, no need to install anything except the buf CLI if you want to follow along.
$ buf generate --template buf.gen.yaml buf.build/acme/petapis
❌ The problem is the generated Go code is missing dependencies and thus will not compile:
could not import github.com/mfridman/buf-generate-twirp-go/go/payment/v1alpha1
(no required module provides package "github.com/mfridman/buf-generate-twirp-go/go/payment/v1alpha1")
💡 You could add the --include-imports option to buf generate, but this will result in a failure due to the way the Twirp plugin works:
$ buf generate --include-imports --template buf.gen.yaml buf.build/acme/petapis
error:files have conflicting go_package settings, must be the same: "money" and "paymentv1alpha1"
Taking a step back, the example in this repository is using 2 modules hosted on the BSR:
The acme/petapis module has a dependency on acme/paymentapis1 and datetime.proto (googleapis)2.
The acme/paymentapis module has a dependency on money.proto3.
If you're curious why the buf templates use except for googleapis, head over to the docs tour for more details.
The solution in most cases is to split up code generation into multiple steps.
Whereby we generate the dependent code using a separate template. If you have a large dependency graph this may get out of hand, but is usually fine.
✅ To get around the error above, we can use the --template option with a separate template file to generate the dependant Go code like so:
$ buf generate --template buf.gen-go.yaml buf.build/acme/paymentapis
To summarize, instead of generating all the code in one shot using buf.gen.yaml, we use buf generate with the --template option to split up code generation. This is often necessary for plugins such as Twirp.
This repo is a working example. Make sure to install the buf cli.
Generated code is purposefully not check in, you generate it :)
$ rm -rf go || true
# generate Go and Twirp code
$ buf generate --template buf.gen.yaml buf.build/acme/petapis
# generate dependant Go code (not using Twirp plugin)
$ buf generate --template buf.gen-go.yaml buf.build/acme/paymentapis
$ go run cmd/server/main.go
Output:
dante PET_TYPE_DOG
dante PET_TYPE_DOG
dante PET_TYPE_DOG
... every 1 second