Use buf to generate definitions for dependencies

[metaturso]

Hi,

I've recently discovered the buf tool and was wondering, can I use it to pull in and compile a protobuf definition in a project that doesn't have any .proto files of its own?

My project depends on a third-party API that ships with a buf.yaml file and publishes their module on the BSR. I can compile the SDK in the target language using the command:

buf generate https://github.com/third-party/api.git
# alternatively pulling the module from BSR
buf generate buf.build/third-party/api

When I call buf generate with a module name as shown above, the code is generated according to the buf.gen.yaml configuration and the SDK in the target language shows up inside the var/ directory. Perfect. Now, I would like to declare the dependency in the YAML configuration instead:

# buf.yaml in my project
version: v1
breaking:
  use:
    - FILE
lint:
  use:
    - DEFAULT
deps:
  - buf.build/third-party/api

# buf.gen.yaml
version: v1
plugins:
  - name: php
    out: var/

However, when I run buf generate without arguments nothing happens. Here's an example of what I get

buf mod update
buf generate --debug --verbose
DEBUG	get_ref	{"duration": "38.037µs"}
DEBUG	get_config	{"duration": "147.738µs"}
DEBUG	get_config	{"duration": "491.131µs"}
DEBUG	get_config	{"duration": "79.544µs"}
DEBUG	get_module_config	{"duration": "1.626034ms"}
DEBUG	command	{"duration": "43.218858ms"}
Failure: no .proto target files found

Any advice?

[nicksnyder]

buf.yaml is for declaring a Protobuf module. If you have no proto files in your repo, then you don't need a buf.yaml.

If you are just trying to use/call APIs defined in modules outside of your project, then you just need to define and configure your own buf.gen.yaml and call buf generate.

With v1 buf.gen.yaml, if you want to generate code for multiple inputs, you need to call buf generate multiple times (and have a separate buf.gen.yaml for each invocation of buf generate.

We just released a v2 format for buf.gen.yaml which makes this use case easier, so recommend you checking that out too.

• Blog
• v1 buf.gen.yaml
• Migrating to v2 buf.gen.yaml

For completeness, Generated SDKs are another option. They make it possible to download generated code directly from the BSR for your language so you don't need to manage code generation at all. Generated SDKs doesn't support PHP though, and it looks like you might be trying to generate PHP code so this might not be an option for you, but I wanted to mention this in case you ever need to generate for other languages.

Hope that helps!