NodeJS require paths are relative to the proto/grpc rule

[mmatheson]

The require path for the _pb.js files generated by the nodejs_* rules is inconsistent with other language implementations.

In the cpp example:
#include "example/proto/routeguide.grpc.pb.h" matches the location of the routeguide proto in the repo (example/proto/routeguide.proto).

In the nodejs example: require('routeguide/routeguide_pb/example/proto/routeguide_pb.js') appears to be {path/to/nodejs_grpc_library}/example/proto/routeguide.proto. This inconsistency leads to long, hard to parse require paths, and obscures the actual location of the .proto file when reading source code.

[aaliddell]

This is because the cc_library rule provides a mechanism for expressing the include root with the includes attribute, which allows us to hide the generated prefix. With js_library, we are only able to provide the package name, which in this case is routeguide. The path is then generated statically for any srcs: https://github.com/bazelbuild/rules_nodejs/blob/2c2cc6eec42b0f4f805fb3063920107b78f821fd/internal/js_library/js_library.bzl#L226

To fix this, we'd either need to have support from rules_nodejs for producing a package that has a path pointing into the routeguide_pb directory (similar to prefix stripping in other rules) or otherwise wrap/patch the produced LinkablePackageInfo provider to amend the path.

In either case, the import would become require('routeguide/example/proto/routeguide_pb.js'), not just require('example/proto/routeguide_pb.js'), since a package name is needed regardless.

[aaliddell]

Pending on bazelbuild/rules_nodejs#2482

[abrmv]

Experiencing the same issue with js_grpc_web_compile - the only workaround I found is to hack the prefix_path attribute to point to the workspace root e.g.

js_grpc_web_compile(
    name = "echo_proto_web",
    protos = [":echo_proto"],
    visibility = ["//visibility:public"],
    prefix_path = "../../.."
)

[aaliddell]

There will hopefully be a fix for this coming: bazelbuild/rules_nodejs#2519

To maintain backwards compatibility, this'll have to be an opt-in mode at least for the 3.x.x cycle.

[aaliddell]

Support for the required prefix stripping feature in rules_nodejs landed in 3.2.3, meaning I can begin looking to implement this.

[aaliddell]

This will be fixed in 4.0.0. The require path will by default have the name_pb removed, with an option to use the old behaviour