Creating Go Code-only Functions

Go archive requirements

For Go code-only functions:

• The executable must be a statically linked, self-contained Linux executable binary.
• The executable file must be named func.
• Go binaries are architecture-specific.
• A binary built for macOS or Windows cannot run directly in the OCI Functions Linux runtime.
• A binary built for x86 cannot run on ARM.
• A binary built for ARM cannot run on x86.
• Multi-architecture applications require one binary per architecture.

Go build target values

Build the Go executable for Linux and for the processor architecture used by the OCI Functions application.

Single-architecture Go archive

For a single-architecture application, package a statically linked, self-contained Linux executable binary named func at the archive root.

archive-root/
├── func
└── resources/  # optional

Rules:

• func is required at the archive root.
• resources/ is optional.
• The archive is invalid if func is missing.
• The binary must be statically linked, self-contained, and built for Linux and for the target architecture of the application.

Example for x86:

GOOS=linux GOARCH=amd64 go build -o func .
zip function.zip func

Example for ARM:

GOOS=linux GOARCH=arm64 go build -o func .
zip function.zip func

If using resources:

zip -r function.zip func resources/

Multi-architecture Go archive

For a multi-architecture application, package a statically linked, self-contained Linux executable binary named func for each supported architecture in the corresponding architecture directory.

archive-root/
├── fn-arch-x86/
    ├── func
    └── resources/  # optional
└── fn-arch-arm/
    ├── func
    └── resources/  # optional

Rules:

• fn-arch-x86/ is required.
• fn-arch-arm/ is required.
• Each architecture directory must contain a binary named func.
• The archive is invalid if either architecture directory is missing.
• The archive is invalid if either architecture directory is missing func.
• Each binary must be statically linked, self-contained, and built for Linux and for the corresponding architecture.

Example:

mkdir -p fn-arch-x86 fn-arch-arm

GOOS=linux GOARCH=amd64 go build -o fn-arch-x86/func .

GOOS=linux GOARCH=arm64 go build -o fn-arch-arm/func .

zip -r function.zip fn-arch-x86 fn-arch-arm

Optional resources directory

Use the optional resources/ directory for files the function needs at runtime, such as static files, templates, or configuration files.

For single-architecture archives, place resources/ at the archive root. For multi-architecture archives, place architecture-specific resources under each architecture directory if needed.

Creating a Go code-only function

To create a Go code-only function, follow the instructions in Creating Code-only Functions. For example, to create a Go code-only function using the Console:

1. On the Applications list page, select the application in which you want to create the Go code-only function. If you need help finding the list page or the application, see Listing Applications.

2. Select the Functions tab.

   The Functions list page opens. All functions in the selected application are displayed in a table.

3. Select Create from archive and specify details for the Go code-only function, including the file source, the Go archive, and the supported runtime for Go code-only functions.

   For Go code-only functions, do not specify a separate handler value. The archive must contain a Linux executable named func in the required location.

4. Specify other details for the function as required (see Creating Code-only Functions).
5. Select Create to create the function.

   The Go code-only function is created and can be invoked like any other function.

Troubleshooting