how to get the dependencies and their versions for go executables built with bazel

[blumamir]

Hi,

Me and https://github.com/RonFed are working on OpenTelemetry auto instrumentation module. This issue is regarding the one here

In order to correctly instrument a go binary, we need to extract the dependencies and their versions from the executable file.

We use the debug/buildinfo from the standard library, doing something similar to this:

import  (
  "debug/buildinfo"
)

	f, err := os.Open("/path/to/go/executable")
	if err != nil {
		fmt.Println("Error:", err)
		return
	}
	defer f.Close()

	bi, err := buildinfo.Read(f)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	fmt.Println("deps:")
	fmt.Println(bi.Deps)

When running this inspection on a binary built with go build and go.mod, we are able to see the deps in the executable. However, when inspecting an executable built with bazel, the deps are not there.

Example sections from our build configuration:

BUILD.bazel

go_library(
    name = "rolldice_lib",
    srcs = [
        "main.go",
        "rolldice.go",
    ],
    importpath = "github.com/tendermint/tendermint/rolldice",
    visibility = ["//visibility:private"],
    deps = [
        "@com_github_gin_gonic_gin//:go_default_library"
    ],
)

deps.bzl

...
    go_repository(
        name = "com_github_gin_gonic_gin",
        build_file_proto_mode = "disable_global",
        importpath = "github.com/gin-gonic/gin",
        sum = "h1:nTuyha1TYqgedzytsKYqna+DfLos46nTv2ygFy86HFU=",
        version = "v1.10.0",
    )
...

How can we get this info from a binary built with bazel? Any help will be appreciated

[gscho]

I'm running into the same issue where bazel built binaries do not return anything when executing go version -m <path-to-bin> but binaries built with go build return all the embedded modules and their versions.

[fmeum]

We can inject data, but it's not clear what data that should be. Bazel Go targets can depend on Go code that isn't even a Go module. PRs that wire this up in any reasonable way are welcome though, I'm happy to support them as well.