Moving applications to containers can require some considerable development efforts. One of the important transitions is the application’s configuration. In traditional deployments, configuration is usually performed “individually” on the target server. Some organizations use deployment or automation tools, others might even do that manually.

As part of their configuration, most applications will require different credentials for accessing services they consume (database, APIs,.. ). HashiCorp’s Vault is a great tool to manage such data.

In some cases, an application can hardly be changed in order to be able to get its configuration from another source than the traditional server config file. You might then want to develop a utility that can prepare a configuration file before the application get started. Having to develop such utilities led me to write my first go library:

vaultlib

Is a simple, lightweight go library allowing to easily read secrets from Vault KV using it’s HTTP APIs.

It currently offers the following features:

• Can be configured through environment variables or programmatically.
• Vault connection through AppRole or token.
• Vault KV secrets (v1 and v2)
• Token renewal management
• Execute raw queries against Vault

Example

Assuming we have our K/V secret in Vault at secret/path/my-secret

package main

import (
	"fmt"
	"log"

	vault "github.com/mch1307/vaultlib"
)

func main() {
    // Create a new config. Reads env variables, fallback to default value if needed
    vcConf := vault.NewConfig()

    // Create new client
	vaultCli, err := vault.NewClient(vcConf)
	if err != nil {
		log.Fatal(err)
	}

    // Get the Vault secret kv_v2/path/my-secret
	secret, err := vaultCli.GetSecret("secret/path/my-secret")
	if err != nil {
		fmt.Println(err)
	}

    // We know our secret is a key/value so we use secret.KV
    // if our secret was of JSON type, we would have used secret.JSONSecret
	for k, v := range secret.KV {
		fmt.Printf("Secret %v: %v\n", k, v)
	}
}

The project is available here. It contains a sample folder with working example. You can consult the GoDoc for the complete package documentation.

Hope it’s usefull ;)