The source for this tutorial is too complicated

[johnlabarge]

What I needed at least was something more minimal that showed off the project structure that makes sense for a server and client stub. This has lots of dependent modules and it's hard to get your head around how to use it in real life.

[jamesward]

Yeah I agree. For now, here is a more minimal example that might help:
https://github.com/GoogleCloudPlatform/kotlin-samples/tree/main/run/grpc-hello-world-gradle

[dkthezero]

@jamesward do you have the same example for bazel? support for bzlmod with MODULE.bazel is appreciated

[jamesward]

The examples in this repo have bazel builds. Let me know if that helps.

[dkthezero]

@jamesward I have looked around all examples, but you use the rules but do not setup it up from scratch.

I practice with Bzlmod, a new way to maintain the Bazel in the next release 7.0, can you help me to resolve it:

• Add the grpc-kotlin into project

## MODULE.bzl
# =========================================
# Custom rule for grpc-kotlin v1.3.0
# =========================================
bazel_dep(name = "grpc_kotlin", repo_name = "grpc_kotlin")

archive_override(
    module_name = "grpc_kotlin",
    urls = ["https://github.com/grpc/grpc-kotlin/archive/refs/tags/v1.3.0.tar.gz"],
)

• Use it

## protos/BUILD
package(default_visibility = ["//visibility:public"])

load("@rules_proto//proto:defs.bzl", "proto_library")
load("@grpc_kotlin//kt_jvm_grpc.bzl", "kt_jvm_grpc_library", "kt_jvm_proto_library")

proto_library(
    name = "embedded_proto",
    srcs = [
        "inits.proto",
        "specs.proto",
    ],
    deps = [],
)

kt_jvm_proto_library(
    name = "embedded_kt_proto",
    deps = [":embedded_proto"],
)

kt_jvm_grpc_library(
    name = "embedded_kt_grpc",
    srcs = [":embedded_proto"],
    deps = [":embedded_kt_proto"],
)

kt_jvm_grpc_library(
    name = "embedded_kt_grpc_lite",
    srcs = [":embedded_proto"],
    flavor = "lite",
    deps = [":embedded_kt_proto"],
)

Then I got error while build:

Loading: 
ERROR: Error computing the main repository mapping: MODULE.bazel expected but not found at /private/var/tmp/_bazel_dkthezero/aedcf60688cfee836e103ea62b320c98/external/grpc_kotlin~override/MODULE.bazel

[dkthezero]

Another setup is:

## grpc_kotlin.bzl
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

def grpc_kotlin():
    release = "v1.3.0"
    http_archive(
        name = "grpc_kotlin",
        urls = ["https://github.com/grpc/grpc-kotlin/archive/refs/tags/%s.tar.gz" % release],
    )

def _grpc_kotlin_repositories(ctx):
    grpc_kotlin()

grpc_kotlin_dependencies = module_extension(
    implementation = _grpc_kotlin_repositories,
)

## MODULE.bzl
grpc_kotlin_dependencies = use_extension("//:grpc_kotlin.bzl", "grpc_kotlin_dependencies")
use_repo(grpc_kotlin_dependencies, "grpc_kotlin")

Then when we build:

ERROR: error loading package 'embed/kotlin/vn/uhand/embed/proto': Every .bzl file must have a corresponding package, but '@_main~grpc_kotlin_dependencies~grpc_kotlin//:kt_jvm_grpc.bzl' does not have one. Please create a BUILD file in the same or any parent directory. Note that this BUILD file does not need to do anything except exist.
ERROR: Skipping '//embed/kotlin/vn/uhand/embed/proto/...:all': no targets found beneath 'embed/kotlin/vn/uhand/embed/proto'

[ekohlwey]

I attempted to get this to work. It is very close but there is a problem with the external dependency name being mangled. This is what I have, in case anyone is able to get something working based on it:

# grpc_kotlin.bzl
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")


def grpc_kotlin():
    grpc_kotlin_version = "1.4.1"
    http_archive(
        name = "com_github_grpc_grpc_kotlin",
        urls = ["https://github.com/grpc/grpc-kotlin/archive/refs/tags/v%s.tar.gz" % grpc_kotlin_version],
        strip_prefix = "grpc-kotlin-%s" % grpc_kotlin_version,
    )
    grpc_java_version = "1.60.1"
    http_archive(
        name = "io_grpc_grpc_java",
        urls = ["https://github.com/grpc/grpc-java/archive/refs/tags/v%s.tar.gz" % grpc_java_version],
        strip_prefix = "grpc-java-%s" % grpc_java_version,
    )
    protobuf_version = "25.1"
    http_archive(
        name = "com_google_protobuf",
        urls = ["https://github.com/protocolbuffers/protobuf/releases/download/v25.1/protobuf-%s.tar.gz" % protobuf_version],
        strip_prefix = "protobuf-%s" % protobuf_version,
    )
    rules_ruby_version = "0.6.0"
    http_archive(
        name = "rules_ruby",
        strip_prefix = "rules_ruby-%s" % rules_ruby_version,
        urls = [
            "https://github.com/protocolbuffers/rules_ruby/archive/v%s.zip" % rules_ruby_version,
        ],
    )


def _grpc_kotlin_repositories(ctx):
    grpc_kotlin()

grpc_kotlin_dependencies = module_extension(
    implementation = _grpc_kotlin_repositories,
)

# MODULE.bazel

maven.install(
    artifacts = [
        "com.google.errorprone:error_prone_annotations:2.3.2",
        "com.squareup:kotlinpoet:1.15.3",
        "com.google.guava:guava:31.1-jre",
        "com.google.guava:failureaccess:1.0.2",
    ],
    generate_compat_repositories = True,
)

use_repo(
    maven,
    "maven",
    "com_google_guava_guava",
    "com_google_j2objc_j2objc_annotations",
    "com_google_code_findbugs_jsr305",
    "com_google_errorprone_error_prone_annotations",
    "com_google_guava_failureaccess",
)

Fails with:

ERROR: /private/var/tmp/_bazel_ekohlwey/80429706e7731d7db50de017c57ccb50/external/_main~grpc_kotlin_dependencies~com_github_grpc_grpc_kotlin/compiler/src/main/java/io/grpc/kotlin/generator/BUILD.bazel:9:15: no such target '@rules_jvm_external~5.3~maven~com_google_guava_guava//:com_google_guava_guava': target 'com_google_guava_guava' not declared in package '' defined by /private/var/tmp/_bazel_ekohlwey/80429706e7731d7db50de017c57ccb50/external/rules_jvm_external~5.3~maven~com_google_guava_guava/BUILD (Tip: use `query "@com_google_guava_guava//:*"` to see all the targets in that package) and referenced by '@_main~grpc_kotlin_dependencies~com_github_grpc_grpc_kotlin//compiler/src/main/java/io/grpc/kotlin/generator:generator'
ERROR: Analysis of target '//Service:Service' failed; build aborted: 

The output of the query command shows that the target name is mangled, matching the sub-repo naming conventions that bzlmod uses.

bazel query "@com_google_guava_guava//:*"
@com_google_guava_guava//:BUILD
@com_google_guava_guava//:rules_jvm_external~5.3~maven~com_google_guava_guava

I created bazel-contrib/rules_jvm_external#1016 in the hopes that someone can look into the name mangling issue.