What are Go Tools?

Something that makes your life much easier as a developer.

Go isn’t just about a programming language.

It's also coming bundled with a very useful set of tools.

You can see a list of commands available with “go” binary like following

Last login: Mon Aug 22 10:42:08 on ttys001
➜  ~ go
Go is a tool for managing Go source code.
Usage:
go <command> [arguments]
The commands are:
bug         start a bug report
 build       compile packages and dependencies
 clean       remove object files and cached files
 doc         show documentation for package or symbol
 env         print Go environment information
 fix         update packages to use new APIs
 fmt         gofmt (reformat) package sources
 generate    generate Go files by processing source
 get         add dependencies to current module and install them
 install     compile and install packages and dependencies
 list        list packages or modules
 mod         module maintenance
 work        workspace maintenance
 run         compile and run Go program
 test        test packages
 tool        run specified go tool
 version     print Go version
 vet         report likely mistakes in packages
Use "go help <command>" for more information about a command.
Additional help topics:
buildconstraint build constraints
 buildmode       build modes
 c               calling between Go and C
 cache           build and test caching
 environment     environment variables
 filetype        file types
 go.mod          the go.mod file
 gopath          GOPATH environment variable
 gopath-get      legacy GOPATH go get
 goproxy         module proxy protocol
 importpath      import path syntax
 modules         modules, module versions, and more
 module-get      module-aware go get
 module-auth     module authentication using go.sum
 packages        package lists and patterns
 private         configuration for downloading non-public code
 testflag        testing flags
 testfunc        testing functions
 vcs             controlling version control with GOVCS
Use "go help <topic>" for more information about that topic.
➜  ~

Let’s take a look one by one.

First, “bug” command opens up a browser tab with the right place where you can issue an official bug report so that the bug reporting becomes quite handy.

$ go bug

bug report

and the next command is “build”.

As the name suggests, we use this command to build our Go application as a binary executable file.

This command follows this format : go build -o <output path> <packages>

One example would be like this

➜  go-app-one git:(main) ✗ go build -o cmd/demo2/bin/app cmd/demo2/main.go
➜  go-app-one git:(main) ✗ tree cmd/demo2 
cmd/demo2
├── bin
│   └── app
└── main.go
1 directory, 2 files
➜  go-app-one git:(main) ✗

the command is outputting the executable file “app” to “cmd/demo2/bin”.

“bin” folder is normally where the executable file is located in Go application project.

and the next is “clean”.

It normally gets run with a flag “-modcache”.

Often times, we need to remove all downloaded packages to refresh up the development environment or do some major upgrades of dependencies. Then, this command helps.

$ go clean -modcache

This removes all downloaded packages in $(go env GOPATH)/pkg/mod directory.

This is what it looks like in the directory before getting cleaned.

➜  go-app-one git:(main) ✗ ls -l /Users/yeongseokkim/go/pkg/mod/
total 0
drwxr-xr-x  4 yeongseokkim  staff  128 Aug 23 12:48 cache
drwxr-xr-x  3 yeongseokkim  staff   96 Aug 23 12:48 github.com

And after being cleaned..

➜  go-app-one git:(main) ✗ go clean -modcache
➜  go-app-one git:(main) ✗ ls -l /Users/yeongseokkim/go/pkg/mod/
ls: /Users/yeongseokkim/go/pkg/mod/: No such file or directory
➜  go-app-one git:(main) ✗ ls -l /Users/yeongseokkim/go/pkg/    
total 0
drwxr-xr-x  4 yeongseokkim  staff  128 Aug 25  2021 darwin_amd64
drwxr-xr-x  3 yeongseokkim  staff   96 Jun 21  2021 sumdb
➜  go-app-one git:(main) ✗

no more packages there.

the rest of tools will be covered in the next series…