Using a Go Binary as a Credential Script for Harvest

[rahulguptajss]

Use Case

When running Harvest inside a container, you might encounter environments where tools like jq and curl are not available. In such cases, you can use a Go binary as a credential script to fetch authentication information. This guide explains how to build and use a Go binary for this purpose.

For detailed information on configuring the credentials_script, refer to the Harvest documentation.

Writing the Go Script

1. Create a Go file named main.go with the following content. Note that this is a sample and you will need to modify it to fetch the relevant password for your use case:

   package main
   
   import (
       "fmt"
       "os"
       "strings"
   )
   
   func main() {
       if len(os.Args) < 2 {
           fmt.Println("Please provide an argument.")
           return
       }
   
       address := os.Args[1]
   
       pass := processInput(address)
   
       fmt.Println("password:", pass)
   }
   
   func processInput(address string) string {
       if address != "" {
           // process and return password
           // Add custom logic to fetch password for the address
           return strings.ToUpper(address)
       }
       return ""
   }

Building the Go Binary

2. Build the Go binary for Linux with the following command:

   GOOS=linux GOARCH=amd64 go build -o get_credentials main.go

This command will produce a standalone binary named get_credentials that can be executed on a Linux system without requiring the Go framework.

Using the Binary in a Container

3. When running Harvest inside a container, ensure the Go binary is available inside the container. You can achieve this by mounting the binary into the container.

   Example Docker compose file:

services:
  sar:
    image: ghcr.io/netapp/harvest:latest
    container_name: sar
    restart: unless-stopped
    ports:
      - "12990:12990"
    command: '--poller sar --promPort 12990 --config /opt/harvest.yml'
    volumes:
      - ./cert:/opt/harvest/cert
      - ./harvest.yml:/opt/harvest.yml
      - ./conf:/opt/harvest/conf
      - ./get_credentials:/opt/harvest/get_credentials