Go Modules clarified

gomod is a tool that helps Go project maintainers to understand their project's dependencies and it can provide useful information to developers "modularising" non-module projects. It helps you by visualising your dependency graph and, even more, analyse it for your profit. It will help you answer typical questions such as:

  • How can I visualise the network of my dependencies?
  • How old are the versions of my dependencies that I depend on?
  • Are different dependencies of my project using potentially conflicting forks of the same module?
  • What dependency chains lead to github.com/foo/bar and what constraints do they put on versions?
  • Why is dependency github.com/foo/bar used at version 1.12.0 and not at version 1.5.0 as I
    want it to be?

Detailed features

Dependency analysis commands

gomod graph

Create a graphical representations of your dependency graph with the possibility to filter out
noise, add annotations and focus on the pieces of the graph that are of interest to you. You can for
example:

  • Only show dependencies that are required by more than one package.
  • Only show the dependency chains that lead to one or more specified packages.
  • Annotate dependencies with the versions in which they are used and the versions constraint
    imposed by each edge of the graph.

This functionality requires the dot tool which you will need to
install separately. You can produce images in GIF, JPG, PDF, PNG and PS format.

gomod reveal

Show all the places at which your (indirect) module dependencies use replace statements which you
might need to account for in your own go.mod in order to build your project.

gomod analyse

Produce a short statistical report of what is going on with your dependencies. The report includes
things like (in)direct dependency counts, mean and max dependency ages, dependency age distribution,
and more.

NB: This command can also be invoked as gomod analyze for those who intuitively use American
spelling.

Command-line use

The sub-commands of gomod completion provide you with the benefit of shell auto-completion making
it easier to cycle through the available sub-commands and flags.

Bash

Besides completion for static elements such as commands and flags, the auto-complete functionality
for Bash also provides some context-specific completion such as the dependency names of your current
project.

If you only want completion to be added to your current shell you can simply run

source <(gomod completion bash)

If you want to have it added by default to each shell instance that you start you can add the
following to your .bashrc, .profile (Linux) or .bash_profile (MacOS / OSX)

# Provide Bash auto-completion for the 'gomod' tool if it's in the PATH.
if [[ -n "$(which gomod)" ]]; then
   source <(gomod completion bash)
fi

Powershell

In order to auto-completion by default to each shell instance that you start you can add the
following to your PowerShell profile

if (Get-Command "gomod" -errorAction SilentlyContinue) {
   $tmp = New-TemporaryFile
   gomod completion ps | Out-File $tmp.FullName
   . $tmp.FullName
   Remove-Item $tmp.FullName
}

ZSH

If you only want completion to be added to your current shell you can simply run

source <(gomod completion zsh)

If you want to have it added by default to each shell instance that you start you can add the
following to your .bashrc, .profile (Linux) or .bash_profile (MacOS / OSX)

# Provide ZSH auto-completion for the 'gomod' tool if it's in the PATH.
if [[ -n "$(which gomod)" ]]; then
   source <(gomod completion zsh)
fi

Example output

Full dependency graph

The entire dependency graph for the gomod codebase, using clustering to reduce the image size.
full

Shared dependencies

Graph with only the shared dependencies for the gomod project.
shared-dependencies

Dependency chains

Specific zoom on the dependency chains leading to the github.com/stretchr/testify and
golang.org/x/sys modules with version annotations.
dependency-chains

Hidden replace's

 -> gomod reveal
'github.com/Rhymen/go-whatsapp' is replaced:
   maunium.net/go/mautrix-whatsapp -> github.com/tulir/go-whatsapp @ v0.0.2-0.20190528182350-fde573a2a73b

'gopkg.in/russross/blackfriday.v2' is replaced:
 ✓ maunium.net/go/mautrix            -> github.com/russross/blackfriday/v2 @ v2.0.1
 ✓ maunium.net/go/mautrix-appservice -> github.com/russross/blackfriday/v2 @ v2.0.1
 ✓ maunium.net/go/mautrix-whatsapp   -> github.com/russross/blackfriday/v2 @ v2.0.1

[✓] Match with a top-level replace in 'github.com/42wim/matterbridge'

Dependency statistics

Statistical analysis of the Matterbridge dependency graph.

 -> gomod analyse
-- Analysis for 'github.com/42wim/matterbridge' --
Dependency counts:
- Direct dependencies:   69
- Indirect dependencies: 51

Age statistics:
- Mean age of dependencies: 14 month(s) 15 day(s)
- Maximum dependency age:   82 month(s) 19 day(s)
- Age distribution per month:

  16.67 % |        #
          |        #
          |        #
          |        #
          |    #   #
          |#   #   #
          |#   #   #
          |#   #   #
          |#   # _ #
          |#   # # #
          |#   # # #
          |#   # # #
          |#   # # #
          |#   # # # # #   #
          |# _ # # # # #   #
          |# # # # # # #   #
          |# # # # # # # # #     #
          |# # # # # # # # #     #   # #
          |# # # # # # # # #     # # # #     #     # #
          |# # # # # # # # #   # # # # #   # # # # # # #     # #   #           #             #
   0.00 % |___________________________________________________________________________________
           0                                                                                84

Reverse dependency statistics:
- Mean number of reverse dependencies:    1.40
- Maximum number of reverse dependencies: 9
- Reverse dependency count distribution:

  83.33 % |  #
          |  #
          |  #
          |  #
          |  #
          |  #
          |  #
          |  #
          |  #
          |  # _
   0.00 % |___________________
           0                10

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