Handy well-known and less-known tools for Go projects
- Tests
- Dependencies
- ➡ Get Go version of current module
- ➡ Get Go versions of upstream modules
- ➡ Get directly dependent modules that can be upgraded
- ➡ Get upstream modules without Go version
- ➡ Get available module versions
- ➡ Make graph of upstream packages
- ➡ Scrape details about upstream modules and make graph
- ➡ Scrape licences of upstream dependencies
- ➡ Explore upstream dependencies interactively
- ➡ Make graph of function calls in package
- Assembly
- Execute
- Refactoring
- Errors
- Build
Visualize distribution of code coverage in your project. This helps to identify code areas with high and low coverage. Useful when you have large project with lots of files and packages. This 2D image-hash of your project should be more representative than a single number.
First make profile with
go test -coverprofile cover.out ./...
Then turn coverprofile into SVG
go-cover-treemap -coverprofile cover.out > out.svg
Requirements
go install github.com/nikolaydubina/go-cover-treemap@latest
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'
Example
github.com/gin-gonic/gin/ginS
github.com/gin-gonic/gin/internal/json
Requirements
https://stedolan.github.io/jq/download/
This is very helpful tool from the official Go toolchain.
First make profile
go test -coverprofile cover.out ./...
Then open in browser
go tool cover -html=cover.out
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])'
Example
================== 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
Requirements
https://stedolan.github.io/jq/download/
This is in cases when you need to synchronize tests, for example in integration tests that share environment. Official documentation.
go test -p 1 -parallel 1 ./...
Add t.Parallel to your tests case function bodies.
As per documentation, by default -p=GOMAXPROCS and -parallel=GOMAXPROCS when you run go test.
Different packages by default run in parallel, and tests within package can be enforced to run in parallel too.
Make sure to copy test case data to new variable, why explained here.
Official documentation.
Example
...
for _, tc := range tests {
tc := tc
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
...Use this in CI to setup correct Go version automatically from go.mod.
go mod edit -json | jq -r .Go
Example
1.16
Requirements
https://stedolan.github.io/jq/download/
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
Example
1.11 github.com/ugorji/go/codec
1.11 golang.org/x/crypto
1.12 github.com/golang/protobuf
Requirements
https://stedolan.github.io/jq/download/
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 '\['
Example
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]
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
Example
github.com/facebookgo/clock
golang.org/x/text
gopkg.in/yaml.v2
Requirements
https://stedolan.github.io/jq/download/
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
Example
github.com/google/gofuzz v1.0.0 v1.1.0 v1.2.0
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
Requirements
https://stedolan.github.io/jq/download/
https://graphviz.org/download/
$ go install github.com/nikolaydubina/import-graph@latest
$ go install github.com/nikolaydubina/jsonl-graph@latest
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
Requirements
https://graphviz.org/download/
$ go install github.com/nikolaydubina/import-graph@latest
$ go install github.com/nikolaydubina/jsonl-graph@latest
This is tool from Google. Might be useful to collect all the licences or checking if you can use the project for example in propriatary or commercial environment.
go-licenses csv github.com/gohugoio/hugo
Example
github.com/cli/safeexec,https://github.com/cli/safeexec/blob/master/LICENSE,BSD-2-Clause
github.com/bep/tmc,https://github.com/bep/tmc/blob/master/LICENSE,MIT
github.com/aws/aws-sdk-go,https://github.com/aws/aws-sdk-go/blob/master/LICENSE.txt,Apache-2.0
github.com/jmespath/go-jmespath,https://github.com/jmespath/go-jmespath/blob/master/LICENSE,Apache-2.0
github.com/gorilla/websocket,https://github.com/gorilla/websocket/blob/master/LICENSE,BSD-2-Clause
github.com/pelletier/go-toml/v2,https://github.com/pelletier/go-toml/blob/master/v2/LICENSE,MIT
github.com/spf13/cobra,https://github.com/spf13/cobra/blob/master/LICENSE.txt,Apache-2.0
github.com/kyokomi/emoji/v2,https://github.com/kyokomi/emoji/blob/master/v2/LICENSE,MIT
go.opencensus.io,Unknown,Apache-2.0
github.com/Azure/azure-storage-blob-go/azblob,https://github.com/Azure/azure-storage-blob-go/blob/master/azblob/LICENSE,MIT
github.com/yuin/goldmark-highlighting,https://github.com/yuin/goldmark-highlighting/blob/master/LICENSE,MIT
Requirements
go install github.com/google/go-licenses@latest
This is a tool from one of creators of Go. This tool should help explore dependencies and assist large refactorings. Source: https://github.com/adonovan/spaghetti
Requirements
go install github.com/adonovan/spaghetti@latest
This can be helpful to quickly track which packages current package is calling and why.
go-callvis .
Requirements
go install github.com/ofabry/go-callvis
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.
This tool allows to check what does Go compiler do. Might be useful if you trying to optimize some code or learn more about compiler. Website: https://golang.design/gossa Source: https://github.com/golang-design/ssaplayground
This is short and convenient for Go oneliners. This tool will print to stdout the return of a function call.
Example
$ cat README.md | gorram crypto/sha1 Sum
c8faff3af2e6816800a8b83af8e3535872ec6120
Selected Usecases
echo 12345 | gorram encoding/base64 StdEncoding.EncodeToStringcat myfile.txt | gorram crypto/sha1 Sumgorram net/http Get https://google.com
Requirements
go install github.com/natefinch/gorram@latest
This is similar to famous oneliner in Python python3 -m http.server and python -m SimpleHTTPServer.
Create file like this
package main
import (
"net/http"
)
func main() {
http.ListenAndServe(":9000", http.FileServer(http.Dir(".")))
}Then run this file (e.g. if named fs.go)
go run fs.go
This tool from Google has lots of useful features like monitoring memory of Go processes, forcing GC, getting version of Go of process.
$ gops
983 980 uplink-soecks go1.9 /usr/local/bin/uplink-soecks
52697 52695 gops go1.10 /Users/jbd/bin/gops
4132 4130 foops * go1.9 /Users/jbd/bin/foops
51130 51128 gocode go1.9.2 /Users/jbd/bin/gocode
Requirements
go install github.com/google/gops@latest
This tool creates 3D visualization of coroutines execution. There is no advanced functions and it is hard to analyze production systems. However, it could be insteresting for educational purposes. Source: https://github.com/divan/gotrace
Requirements
You may need to run Docker container with that tool or install locally and patch Go compiler. More instructions in the original repo.
go install github.com/divan/gotrace
I found this in annoncement notice of Go 1.18 for changes to interface{} to any.
This can be useful for other refactorings too.
gofmt -w -r 'interface{} -> any' .
This tool will be useful for reading panic messages.
Need to redirect STDERR to this tool with panic stack traces.
The tool has HTML outpout and does lots of deduplication and enhansements.
Refer to examples in original repo.
go test -v |& pp
Requirements
go install github.com/maruel/panicparse/v2/cmd/pp@latest
Disable cgo with CGO_ENABLED=0 and enable with CGO_ENABLED=1.
If you don't, cgo may end-up being enabled or code dynamically linked if, for example, you use some net or os packages.
You may want to disable cgo to improve performance, since complier and runtime would have easier job optimizing code.
This also should reduce your image size, as you can have alpine image with less shared libraries.