How to get Go detailed build logs, with all used packages in GOPATH and "go module" mode?

Question

I have situation with a project.

It behave different when i use go module, outside GOPATH, and "go get" inside GOPATH. In both cases build goes without errors.

But GPRC connection behaves differently. Gives timeout in "go mod" case, works fine with "go get".

I suspect that go uses different set of packages. I need full list of used packages with versions in both modes to compare. How can i access it?

Answer 1

For listing installed packages using GOPATH, please see this old thread: How to list installed go packages

The following applies to the new module mode.

At compile / build time

You may use the go list -m all command to view final versions that will be used in a build for all direct and indirect dependencies (source). You can read more details about this here: Modules: Version Selection.

At runtime

At runtime (from your application) you may use the debug.ReadBuildInfo() function:

ReadBuildInfo returns the build information embedded in the running binary. The information is available only in binaries built with module support.

Note: debug.ReadBuildInfo() was only added in Go 1.12 (released just a day ago).

Example getting and printing build info (recursively). Easiest is to JSON-marshal the build info:

bi, ok := debug.ReadBuildInfo()
if !ok {
    fmt.Println("Getting build info failed (not in module mode?)!")
    return
}

enc := json.NewEncoder(os.Stdout)
enc.SetIndent("", "  ")
if err := enc.Encode(bi); err != nil {
    panic(err)
}

Example output

Example output for a project which has a single dependency: github.com/globalsign/mgo).

Running go list -m all:

mytest
github.com/globalsign/mgo v0.0.0-20181015135952-eeefdecb41b8

Getting and JSON-marshaling the build info at runtime:

{
  "Path": "mytest",
  "Main": {
    "Path": "mytest",
    "Version": "(devel)",
    "Sum": "",
    "Replace": null
  },
  "Deps": [
    {
      "Path": "github.com/globalsign/mgo",
      "Version": "v0.0.0-20181015135952-eeefdecb41b8",
      "Sum": "h1:DujepqpGd1hyOd7aW59XpK7Qymp8iy83xq74fLr21is=",
      "Replace": null
    }
  ]
}