This change moves the logic for computing the package name part of an
import directory from python_rules.bzl to protobuf.bzl, and reinstates
the workspace root part of the directory. The effect is that it is now
possible for a py_library_rule to depend on a proto_library in a
different repository whose source files are generated.
This is needed to comply with bazel best practices (each proto file is first processed by proto_library: https://docs.bazel.build/versions/master/be/protocol-buffer.html#proto_library) and generally bring cc_grcp_library rule up to date with latest Bazel changes (the rule hasn't gotten much updates since 2016).
Detailed description.
Bazel has native `cc_proto_library` rule, but it does not have `cc_grpc_library`. The rule in cc_grpc_library in this repo seems like the best candidate.
This change makes possible using `cc_grpc_library` to generate on grpc library, and consume protobuf protion as dependencies. The typical `BUILD.bazel` file configuraiton now should look like the following:
```python
proto_library(
name = "my_proto",
srcs = ["my.proto"],
)
cc_proto_library(
name = "my_cc_proto",
deps = [":my_proto"]
)
cc_grpc_library(
name = "my_cc_grpc",
srcs = [":my_proto"],
deps = [":my_cc_proto"]
)
```
This allows to decouple all thre phases: proto descriptors generation (`proto_library`), protobuf messages library creation (`cc_proto_library`), grpc library creatio (`cc_grpc_library`).
Notice how `cc_grpc_library` depends on `proto_library` (as `src`) and on `cc_proto_library` (as `deps`). Currently cc_grpc_library is designed in a way that it encapsulates all of the above and directly accepts .proto files as srcs.
The previous version (before this PR) of cc_proto_library was encapsulating all of the 3 phases inside single `cc_proto_library` and also was doing it manually (without relying on the native `cc_proto_library`).
The `cc_proto_library` is kept backward-compatible with the old version.
-) Fixing Bazel 0.4.x breakage
-) Adding helloworld BUILD examples
-) Fixing grpc++ missing files.
-) Adding helloworld example as a test for Bazel basic.
Richard Belleville
Thomas Köppe
Craig Tiller
Yannic Bonenberger
Nicolas Noble
Zhen Lian
Esun Kim
vam
Bill Feng
Jan Tattermusch
Alexander Polcyn
Vijay Pai
Nicolas "Pixel" Noble
yang-g