How do you set the application icon in golang?

I've just created my first go application on Windows.

How do I give it an icon?

There doesn't seem to be any build flags to do this, and I know golang doesn't support resources.

You can use a tool like akavel/rsrc in order to generate a .syso file with specified resources embedded in .rsrc section, aimed for consumption by Go linker when building Win32 excecutables.

See as an example the lxn/walk application, which embeds other metadata in its executable.

rsrc [-manifest FILE.exe.manifest] [-ico FILE.ico[,FILE2.ico...]] -o FILE.syso

-ico="": comma-separated list of paths to .ico files to embed

This differs from embedding binary data into a go program.
For that, use jteeuwen/go-bindata.

> To access asset data, we use the Asset(string) []byte function which is included in the generated output.

data := Asset("pub/style/foo.css")
if len(data) == 0 {
    // Asset was not found.
}

// use asset data

Update 2021: as noted in John N's answer, you can also use:

github.com/tc-hib/go-winres

> A simple command line tool for embedding usual resources in Windows executables built with Go:
>
> - A manifest
> - An application icon
> - Version information (the Details tab in file properties)
> - Other icons and cursors

It can be used as a library too.

The topic is long time, in fact mingw is only requirement, we don't need 3rd party dependency. In addition, resource file *.rc is mandatory for win32 executable application. At last, you can find the demo in rc-demo

1. Install mingw using Chocolatey: choco install mingw

2. Create main.exe.manifest file

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
   <assemblyIdentity
   version="1.0.0.0"
   processorArchitecture="x86"
   name="controls"
   type="win32"
   />
   <dependency>
   <dependentAssembly>
   <assemblyIdentity
   type="win32"
   name="Microsoft.Windows.Common-Controls"
   version="6.0.0.0"
   processorArchitecture=""
   publicKeyToken="6595b64144ccf1df"
   language=""
   />
   </dependentAssembly>
   </dependency>
   </assembly>

3. Create main.rc file

   100 ICON "main.ico"
   100 24 "main.exe.manifest"
   101 RCDATA "content.zip"

4. Build

In git-bash windows perform the following command:
windres -o main-res.syso main.rc && go build -i

1: https://gitlab.com/gozoo/rc-demo "demo"

None of the above answers worked for me. The only way I could get an ico embedded into a GO exe was with Resource Hacker.

http://www.angusj.com/resourcehacker/

1. Install and open Resource Hacker
2. Open compiled exe in Resource Hacker
3. Action > Add an image or other binary resource
4. Select ICO > Add Resource
5. Save and Close

You can also run it directly from the command line if you need to add it to your build scripts.

ResourceHacker -open main.exe -save output.exe -action addskip -res main.ico -mask ICONGROUP,MAIN,

There is a github package GoVersionInfo by Joseph Spurrier:

> Microsoft Windows File Properties/Version Info and Icon Resource Generator for the Go Language
>
> Package creates a syso file which contains Microsoft Windows Version Information and an optional icon. When you run "go build", Go will embed the version information and an optional icon and an optional manifest in the executable. Go will automatically use the syso file if it's in the same directory as the main() function.

This worked out for me

go get github.com/akavel/rsrc
rsrc -ico YOUR_ICON_FILE_NAME.ico
go build

This works well:

go install github.com/tc-hib/go-winres@latest
go-winres simply --icon youricon.png
go build

If your app has a GUI:
go-winres simply --icon icon.png --manifest gui

I delved into this issue for my requirements and the simple methods mentioned by John N and Coconut did not work as expected.

After more delving i figure out what was the problem and I share it so it might be useful for others.

• the syso file need to be part of a package used by the application.
• the syso file cant be placed in the root of the project when there is a cmd/main.go file used for the build.
• the syso file cant be placed in the main package of your application (i.e. placing the syso under cmd when building cmd/main.go file wont make it).

couple examples that worked for me:

flat project structure

...\test1
│   go.mod
│   main.go
│   rsrc.syso

where go.mod

module test1

go 1.19

and main.go

package main

import (
        "fmt"
)

func main() {
        fmt.Println("test1")
}

then go build created test1.exe as expected

empty package

put syso file in a new folder package and create empty file with the package name, force import this package using _

...\test2
│   go.mod
│
├───cmd
│       main.go
│
└───rsrc
        rsrc.go
        rsrc.syso

where go.mod

module test2

go 1.19

rsrc.go

package rsrc

and main.go

package main

import (
        "fmt"
        _ "test2/rsrc"
)

func main() {
        fmt.Println("test2")
}

then go build -o test2.exe cmd\main.go created test2.exe as expected

piggyback on existing package

place the syso file in a folder package that already used by the project app (Note: that different apps would have the same syso in case they use that package)

...\test3
│   go.mod
│
├───cmd
│       main.go
│
└───other
        other.go
        rsrc.syso

where go.mod

module test3

go 1.19

other.go

package other

func Foo() string {
        return "bar"
}

and main.go

package main

import (
        "fmt"
        "test3/other"
)

func main() {
        fmt.Println("test3")
        fmt.Println(other.Foo())
}

then go build -o test3.exe cmd\main.go created test3.exe as expected

using docker build flow

Dockerized build based on piggybacking on existing package

because, hey someone else probably needs this as well....<br>
use the arch to set it to the proper ARCH if you have multi platform/architecture build flow

...
ARG TARGETARCH
ARG TARGETOS
RUN go install github.com/tc-hib/go-winres@latest
RUN go-winres simply --icon images/icon.png --out other/rsrc --arch ${TARGETARCH}
...
GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -o test3.exe cmd/main.go 
...

hope this helps anyone who got stuck

you ant change a icon first think you know setIcon() method it only alow byte[] format so you first create image and convert into byte[]. so do following procedure.

// define icon path using os.Open()
iconFile, err := os.Open("/home/user/image/icon.png")
if err != nil {
	log.Fatal(err)
}
defer iconFile.Close()

// png.Decode() to convert image path to image
img, err := png.Decode(iconFile)
if err != nil {
	log.Fatal(err)
}

// Then convert the image to byte[] format using bytes.Buffer
buf := new(bytes.Buffer)
err1 := jpeg.Encode(buf, img, nil)
_ = err1

// save the converted byte[] to variable
img_buf := buf.Bytes()

// set the coverted byte[] icon using systray.SetTemplateIcon() method
systray.SetTemplateIcon(img_buf, img_buf)

Thank you!!!