serverless/

Function Controller

The Function Controller is a Kubernetes controller that enables Kyma to manage Function resources. It uses Kubernetes Jobs, Deployments, Services, and HorizontalPodAutoscalers (HPA) under the hood.

Prerequisites

The Function Controller requires the following components to be installed:

• Go

Development

To develop the Function Controller, you need:

• libgit2-dev (v1.5)
• controller-gen (v0.6.2)
• [kustomize](https://github.com/kubernetes-sigs/kustomize/releases/tag/kustomize%2Fv4.5.7) (v4.5.7)

Installing Locally Built Serverless Controller Image on k3d With Serverless

Prerequisite:

• installed Serverless on a cluster

To install serverless-controller from local sources on the k3d cluster run:

make install-controller-k3d

This target:

• scales down the Serverless Operator to prevent reverting further changes made to the serverless-controller deployment
• builds the local image with the serverless-controller image
• tags the local serverless-controller image with its hash to be sure the deployment is updated
• uploads the local image to k3d
• updates the image in the serverless-ctrl-mngr deployment

Running/Debugging serverless-manager Locally

To develop the component as normal binary, set up envs correctly, example envs to use controller.env. You can customize the configuration by editing files in hack dir.

Environment Variables

The Function Controller Uses These Environment Variables:

The Webhook Uses These Environment Variables:

Troubleshooting

Symptom

Function Controller tests keep failing with such an error message: error: Invalid libgit2 version; this git2go supports libgit2 between vA.B.C and vX.Y.Z

Cause

Function Controller tests are failing due to the wrong version of the libgit2 binary. The required version of the binary is 1.1.

Solution

Build and install the libgit2 binary required by the Function Controller on macOS. Follow these steps:

1. Navigate to the root directory and verify the version of git2go:

   cat go.mod | grep git2go
   

   You should get a result similar to this example:

   github.com/libgit2/git2go/v31 v31.4.14
   

2. Go to the git2go page to check which version of libgit2 you must use. For example, for git2go v34, use libigit2 in version 1.5.

3. Clone the libgit2 repository:

   git clone https://github.com/libgit2/libgit2.git
   

4. Check out the sources. In this example, the sources are for git2go v31:

   git checkout v1.1.0
   

5. Build and install the libgit2 binary:

   cmake -DCMAKE_OSX_ARCHITECTURES="x86_64" .
   make install
   

Alternative Solution

There is an alternative method for macOS that relies on brew. If you still see the Invalid libgit2 version error message on macOS, follow these steps:

1. Locate your brew's Cellar directory.

   find / -type d -name "Cellar"
   

Alternatively, you can use ⌘⇧G in Finder to search for Cellar.

1. Prepare the libgit2 directory.

If you already have libgit2 installed via brew you need to delete previous installations found in the libgit2 directory.

Otherwise create an empty directory named libgit2.

1. Extract libgit.tgz located in ./components/serverless/hack into Cellar/libgit2.

2. Link libgit2 using:

   brew link libgit2
   

Symptom

The Function Controller tests keep failing with the following error message:

assertion failed [!result.is_error]: Failed to create temporary file
(ThreadContextFcntl.cpp:84 create_tempfile)

Cause

The Docker engine uses Rosetta for virtualization, which causes issues on M1 Mac.

Solution

Disable the Use Rosetta for x86/amd64 emulation on Apple Silicon option in the Docker Desktop general settings.

Symptom

The Serverless build fails, with the following error message:

dyld[18077]: Library not loaded: @rpath/libgit2.1.5.dylib
  Referenced from: <EE8B6DDF-D4F5-31D6-D722-3406DEBA716B> /Users/I758687/Library/Caches/JetBrains/GoLand2024.3/tmp/GoLand/___go_build_github_com_kyma_project_serverless_components_serverless_cmd_manager
  Reason: no LC_RPATH's found

Cause

In the 2023 release notes for Xcode, Apple mentioned that the linker was rewritten, which could be the root cause of the issue. If you are experiencing similar symptoms, this discussion may be helpful: https://forums.developer.apple.com/forums/thread/737920#766944022

Solution

To resolve the issue, use the -ldflags option with the -r flag set to /usr/local/lib when building Serverless.

Example usage:

go build -ldflags "-r=/usr/local/lib" -a -o manager ./components/serverless/cmd/manager/main.go