Question
Answer and Explanation
Getting the exit command of a Golang program within an Argo workflow typically involves capturing the exit code of the executed Golang application. Argo workflows execute steps in containers, and the exit code of a container's main process (in this case, your Golang application) is how Argo determines success or failure. Here's how you can achieve this:
1. Golang Program Exit Codes:
- In Golang, you control the exit code by using os.Exit(code int) function. By default, if a program exits normally without calling os.Exit, it will return a 0 exit code. Any non-zero value will signal an error. For example, os.Exit(1) would indicate an error, and os.Exit(0) would indicate successful execution.
2. Argo Workflow Capture Exit Code:
- Argo automatically captures the exit code of a container process. If the container's main process exits with a non-zero code, Argo will mark the step as failed. If the process exits with a 0, Argo will mark it as successful. You don't need special configurations to retrieve it directly. Argo does not expose the exact command that returns an exit code, but rather just the exit code itself.
3. Example Argo Workflow YAML:
Here is an example that shows how an exit code is evaluated:
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
generateName: go-exit-code-
spec:
entrypoint: main
templates:
- name: main
container:
image: golang:latest
command: ["go", "run", "."]
source:
main.go |
package main
import (
"fmt"
"os"
)
func main() {
fmt.Println("Executing the Go program...")
// Simulate some logic
err := someOperation()
if err != nil {
fmt.Println("Operation failed, exiting with code 1")
os.Exit(1) // Exit with a non-zero code
}
fmt.Println("Operation successful, exiting with code 0")
os.Exit(0) // Exit with a zero code
}
func someOperation() error {
//Simulate some logic that might error
//return errors.New("failed operation") //Uncomment this to simulate a failure.
return nil
}
4. Explanation:
- This YAML defines a simple Argo workflow step that runs a Golang program.
- The Golang program has a function someOperation() that simulates some operation that might error.
- If the operation fails, the program exits using os.Exit(1) which Argo interprets as a failure. If the operation completes successfully, the program exits using os.Exit(0), which Argo interprets as success.
- Argo uses the image: golang:latest and the command: ["go", "run", "."] to execute the go program.
- You don't need to output anything specific to capture the exit code in Argo; it's captured automatically.
5. Important Considerations:
- Argo will mark the workflow step as failed if the container process exits with non-zero code.
- It doesn't matter what command specifically fails inside the container, Argo will only check the exit code.
- To debug a failed step, you can use Argo's UI or CLI tool to view the logs.
In summary, to get the exit command of a Golang program in Argo, ensure the program uses os.Exit() correctly, then, Argo will capture the exit code, and you can set up your workflow steps to act accordingly based on whether the code is zero (success) or non-zero (failure).