Go recipes 🦩

Handy commands to run in Go projects

GO101: Introduction to Go

First, get familiar with basic commands and read through official documentation on Go toolchain.

$ go build ./...
$ go test ./...
$ go generate ./...
$ go fmt ./...
$ go vet ./...

Find Go versions of upstream modules

Use this when upgrading version of Go or finding old modules.

$ go list -deps -json ./... | jq -rc 'select(.Standard!=true and .Module.GoVersion!=null) | [.Module.GoVersion,.Module.Path] | join(" ")' | sort -V | uniq
1.11 github.com/ugorji/go/codec
1.11 golang.org/x/crypto
1.12 github.com/golang/protobuf
...

Find directly dependent modules that can be upgraded

Use this to keep your modules updated.
Similar function is integrated in VSCode official Go plugin and GoLand.

$ go list -u -m $(go list -m -f '{{.Indirect}} {{.}}' all | grep '^false' | cut -d ' ' -f2) | grep '\['
github.com/goccy/go-json v0.5.1 [v0.7.3]
github.com/golang/protobuf v1.3.3 [v1.5.2]
github.com/json-iterator/go v1.1.9 [v1.1.11]
...

Find upstream modules without Go version

Use this to find outdated modules or imports that you need to upgrade.

$ go list -deps -json ./... | jq -rc 'select(.Standard!=true and .Module.GoVersion==null) | .Module.Path' | sort -u
github.com/facebookgo/clock
golang.org/x/text
gopkg.in/yaml.v2
...

Find available module versions

This works even if you did not download or install module locally.
This is useful to check to which version you can upgrade to, what is the latest version, and whether there are v2+ major versions recognized by Go toolchain.

$ go list -m -versions github.com/google/gofuzz
github.com/google/gofuzz v1.0.0 v1.1.0 v1.2.0

Get assembly of Go code snippets online

Use godbolt.org to compile and see assembly of short Go code.
You can check different platforms and compilers including cgo.
This tool is commonly used by C++ community.

godbolt

Make histogram of Go files per package

Use this to see when package is too big or too small.
Adjust histogram length to maximum value.

$ go list -json ./... | jq -rc '[.ImportPath, (.GoFiles | length | tostring)] | join(" ")' | perl -lane 'print (" " x (20 - $F[1]), "=" x $F[1], " ", $F[1], "\t", $F[0])'
  ================== 18	github.com/gin-gonic/gin
       ============= 13	github.com/gin-gonic/gin/binding
                   = 1	github.com/gin-gonic/gin/internal/bytesconv
                   = 1	github.com/gin-gonic/gin/internal/json
         =========== 11	github.com/gin-gonic/gin/render

Find packages without tests

If code coverage does not report packages without tests.
This should be fast for CI.

$ go list -json ./... | jq -rc 'select((.TestGoFiles | length)==0) | .ImportPath'
github.com/gin-gonic/gin/ginS
github.com/gin-gonic/gin/internal/json
...

Make graph of upstream packages

Use to find unexpected dependencies or visualize project.
Works best for small number of packages, for large projects use grep to narrow down subgraph.
Without -deps only for current module.

$ go list -deps -json ./... | jq -c 'select(.Standard!=true) | {from: .ImportPath, to: .Imports[]}' | jsonl-graph | dot -Tsvg > package-graph.svg

package-graph

Scrape details about upstream modules and make graph

Use to find low quality or unmaintained dependencies.

$ go mod graph | import-graph -i=gomod | jsonl-graph -color-scheme=file://$PWD/basic.json | dot -Tsvg > output.svg

gin-mod-graph-collected

Prerequisites

# get https://graphviz.org/download/
# get https://stedolan.github.io/jq/download/
$ go install github.com/nikolaydubina/[email protected]
$ go install github.com/nikolaydubina/[email protected]
$ go mod download

Contributions

.. are welcomed! 🤝

GitHub

https://github.com/nikolaydubina/go-recipes