SPIKE investigate the need for `-race` Flag and the effect of `CGO_ENABLED=1` on Weave GitOps binary

[chanwit]

User Story

As a Weave GitOps developer, I want to conduct a spike to investigate the need for the -race flag and the effect of CGO_ENABLED=1 on the Weave GitOps project, so that I can better understand their impact on the project's binary.

Outcomes

• An understanding of the -race flag's purpose, benefits, and drawbacks, along with recommendations for its usage within the Weave GitOps binary.
• An understanding of the CGO_ENABLED=1 variable, its impact on the Weave GitOps binary, and how it relates to the -race flag.
• Recommendations for any necessary changes or updates to the Weave GitOps binary based on the findings of the spike.

[chanwit]

Our team has investigated the usage and purpose of the -race flag in the go build command of the Go programming language. This report outlines our findings and recommendations.

Findings

The -race flag is used to enable the race detector in the Go language when building a program (Go Command Documentation). The race detector is a tool designed to identify and diagnose race conditions in concurrent programs. Race conditions arise when a program's behavior is contingent upon the relative timing of events, such as the order in which threads are scheduled to run. These conditions can result in unpredictable behavior and make debugging difficult (Go Blog).

The -race flag in Go requires CGO_ENABLED=1 because the race detector relies on certain C and C++ components for its operation. These components provide the runtime support needed to instrument and analyze the code for potential race conditions. By setting CGO_ENABLED=1, we enable the cgo tool, which allows Go to call C code and interoperate with the C/C++ parts of the race detector. This is essential to ensure the correct functioning of the race detector and its ability to diagnose and report race conditions in Go programs.

The program code is instrumented with additional checks by incorporating the -race flag during the build process. These checks detect data races that may occur during the execution of the program. If a race condition is detected, the program provides a detailed report, including information about the goroutines and memory locations (Go by Example).

Recommendations

We recommend using the -race flag during the development and testing phases based on our findings. This will enable our team to identify and resolve potential race conditions before deploying the application to production. However, it is crucial to note that the -race flag should not be used in production or release builds. The race detector adds significant overhead in CPU usage, memory consumption, and performance (Official Go Documentation). Therefore, it is best to restrict its use to the development and testing stages.

References

1. Go Blog. Introducing the Race Detector. Retrieved from https://go.dev/blog/race-detector
2. Go by Example. Race Detection. Retrieved from https://go-by-example.com/race-detection
3. Go Command Documentation. Compile packages and dependencies. Retrieved from https://pkg.go.dev/cmd/go#hdr-Compile_packages_and_dependencies
4. Official Go Documentation. Data Race Detector. Retrieved from https://golang.org/doc/articles/race_detector.html