wails/v2/cmd/wails/internal/commands/build/README.md

Build

The build command processes the Wails project and generates an application binary.

Usage

wails build <flags>

Flags

Flag	Details	Default
-clean	Clean the bin directory before building
-compiler path/to/compiler	Use a different go compiler, eg go1.15beta1	go
-ldflags "custom ld flags"	Use given ldflags
-o path/to/binary	Compile to given path/filename
-k	Keep generated assets
-tags	Build tags to pass to Go compiler (quoted and space separated)
-upx	Compress final binary with UPX (if installed)
-upxflags "custom flags"	Flags to pass to upx
-v int	Verbosity level (0 - silent, 1 - default, 2 - verbose)	1
-delve	If true, runs delve on the compiled binary	false

The Build Process

The build process is as follows:

• The flags are processed, and an Options struct built containing the build context.
• The type of target is determined, and a custom build process is followed for target.

Desktop Target

• The frontend dependencies are installed. The command is read from the project file wails.json under the key frontend:install and executed in the frontend directory. If this is not defined, it is ignored.
• The frontend is then built. This command is read from the project file wails.json under the key frontend:install and executed in the frontend directory. If this is not defined, it is ignored.
• The project directory is checked to see if the build directory exists. If not, it is created and default project assets are copied to it.
• An asset bundle is then created by reading the html key from wails.json and loading the referenced file. This is then parsed, looking for local Javascript and CSS references. Those files are in turn loaded into memory, converted to C data and saved into the asset bundle located at build/assets.h, which also includes the original HTML.
• The application icon is then processed: if there is no build/appicon.png, a default icon is copied. On Windows, an app.ico file is generated from this png. On Mac, icons.icns is generated.
• The platform assets in the build/<platform> directory are processed: manifest + icons compiled to a .syso file ( deleted after compilation), info.plist copied to .app on Mac.
• If we are building a universal binary for Mac, the application is compiled for both arm64 and amd64. The lipo tool is then executed to create the universal binary.
• If we are not building a universal binary for Mac, the application is built using go build, using build tags to indicate type of application and build mode (debug/production).
• If the -upx flag was provided, upx is invoked to compress the binary. Custom flags may be provided using the -upxflags flag.