Missing dependencies in installation instructions

[haikalpribadi]

Hi,

In the README.md it simply says that we need to add {lang}:deps.bzl to our WORKSPACE file. For example:

git_repository(
    name = "org_pubref_rules_proto",
    remote = "https://github.com/pubref/rules_proto",
    commit = "27da2e7af9e4a1c43c584be2f05be8a301a642b6",
)
load("@org_pubref_rules_proto//java:deps.bzl", "java_grpc_compile")
java_grpc_compile()

However, trying to run java_grpc_compile after this leads to an error:

ERROR: /Users/haikalpribadi/Workspace/repos/graknlabs/grakn/protocol/BUILD:20:1: every rule of type proto_compile implicitly depends upon the target '@com_google_protobuf//:protoc', but this target could not be found because of: no such package '@com_google_protobuf//'

So then I added @com_google_protobuf as a dependency:

http_archive(
    name = "com_google_protobuf",
    sha256 = "0a4c6d0678eb2f063df332cff1a41647ef692c067b5cfb19e51bca778e79d9e0",
    strip_prefix = "protobuf-3.6.1",
    urls = ["https://github.com/protocolbuffers/protobuf/releases/download/v3.6.1/protobuf-all-3.6.1.zip"],
)

Now I get a different error:

ERROR: /private/var/tmp/_bazel_haikalpribadi/3cdeaa1301f056ec7b4e7ee46bda5c79/external/com_github_grpc_grpc/BUILD:2039:1: no such target '//external:protobuf_headers': target 'protobuf_headers' not declared in package 'external' defined by /Users/haikalpribadi/Workspace/repos/graknlabs/grakn/WORKSPACE and referenced by '@com_github_grpc_grpc//:grpc++_config_proto'
ERROR: /private/var/tmp/_bazel_haikalpribadi/3cdeaa1301f056ec7b4e7ee46bda5c79/external/com_github_grpc_grpc/BUILD:388:1: no such target '//external:protobuf_clib': target 'protobuf_clib' not declared in package 'external' defined by /Users/haikalpribadi/Workspace/repos/graknlabs/grakn/WORKSPACE and referenced by '@com_github_grpc_grpc//:grpc_plugin_support'

So I suspected that I'm missing @com_github_grpc_grpc, so I added:

git_repository(
    name = "com_github_grpc_grpc",
    remote = "https://github.com/grpc/grpc",
    tag = "v1.15.1"
)

However, it still gives the error as shown above, so I checked in your WORKSPACE file and saw that you had the following two lines to load grpc_deps.bzl, and I copied them into my WORKSPACE file.

load("@com_github_grpc_grpc//bazel:grpc_deps.bzl", com_github_grpc_grpc_bazel_grpc_deps = "grpc_deps")
com_github_grpc_grpc_bazel_grpc_deps()

Now everything works fine, and the proto files compile. However, I'm worried that I'm doing something wrong/unnecessary above, as you did not put them in your documentation. Thus, my questions are:

1. Is the above code needed in my WORKSPACE? Because I thought {lang}:deps.bzl was going to take care of it. But if it is needed, ...
   a. Why is it needed? If not, then ...
   b. Is there a simpler approach which I should have taken?

[haikalpribadi]

Actually, after I added com_github_grpc_grpc, I can even delete com_google_protobuf:

http_archive(
    name = "com_google_protobuf",
    sha256 = "0a4c6d0678eb2f063df332cff1a41647ef692c067b5cfb19e51bca778e79d9e0",
    strip_prefix = "protobuf-3.6.1",
    urls = ["https://github.com/protocolbuffers/protobuf/releases/download/v3.6.1/protobuf-all-3.6.1.zip"],
)

After deleting the above, my build still works. So in the end, only com_github_grpc_grpc is needed. Why is that?

[haikalpribadi]

Here are my dependencies.bzl and WORKSPACE files for you to see the end result.

[pcj]

Appreciate your understanding, getting started instructions could use some tuneup! Yes, com_grpc_grpc_com and it's grpc_deps() loads alot of dependencies that overlap in other areas.

Effective visualization of the dependency graph of workspace loading rules would be a useful feature in bazel.

[haikalpribadi]

Sorry, I didn't get that, @pcj. Do we actually need to import @com_github_grpc_grpc and not some other configuration?