How to structure Go application to produce multiple binaries?

Question

I am creating three applications which are very similar to each other but each will apply different logic. I am not sure how to best structure it to avoid repeating code.

All applications have the following in common: - read and parse config - setup SQL database connection - gather stats - read from STDIN

Each application will apply different logic to the data read from STDIN.

Would this be considered acceptable? Put all common code in main.go then build as "go build -o bin/app1 main.go app1.go" and so on - pulling in only the app specific logic for each binary to build?

main.go:

func main() {     // db connection     // stats worker     // read from stdin      proccessLine(line) } 

app1.go:

func processLine(line string) {     // logic for app 1 } 

app2.go:

func processLine(line string) {     // logic for app 2 } 

etc.

Answer 1

The following folder structure is used in many popular go projects such as helm,kubicorn etc.

goproject/ ├── bin ├── cmd ├── pkg └── Makefile 

The cmd directory will contain the different binaries, separated in directories.

cmd/ ├── bin1 │   └── main.go ├── bin2 │   └── main.go └── bin3     └── main.go 

pkg directory will contain all your reusable packages. In your case the common code used by the different binaries. This directory can also be named internal , learn more about it here.

pkg ├── reusablepackage1 └── reusablepackage2 

The bin directory is optional, It can be used to store the generated binaries. In case you are generating binaries to $GOBIN this can be omitted.

bin/ ├── bin1 ├── bin2 └── bin3 

The Makefile can be used for writing helpful scripts, such as generating binaries running test suite etc. You can have commands such as make bin1,make bin2 etc.This is optional but I highly recommend this. because it saves me from writing long build commands over and over again.

Answer 2

Usual directory structure for such projects look like that:

cmd/     a/         main.go     b/         main.go 

To build executables run

go build ./cmd/a go build ./cmd/b 

Examples

• https://github.com/prometheus/prometheus/tree/master/cmd