go-vault

• Quickstart
• API Documentation
  • Authentication
  • Vault Endpoint
  • Vault Secret Endpoint
• vault_config.go
  • secretsMap
• pwgen.go
• vault_test.go
• vault.go
• Utility

---

This project was used previously as a way to easily stand up multiple Vault instances with the same footprint. I also migrated from an older vault architecture with duplicate entries to a simpler flat-file approach. I utilized the vault-client-go package.

This was necessary due to a lack of access to Terraform.

Quickstart

Before you begin, make sure you have Docker installed and running.

Demoing the Application

1. Clone the repository and then cd into the project directory.

2. Run the following commands in your terminal inside the project directory:

docker-compose up

3. After the containers have started, access the HashiCorp Vault front-end at http://localhost:8200 and the API is served on http://localhost:4269

4. Log in using Method: Token with the following credentials: dev-only-token

5. Send a POST request to http://localhost:4269/vault with the following JSON object to test. See the Request Documentation for finer details.

// Headers
"x-api-key": "dev-only-token"
"x-vault-url": "http://vault:8200"

{
 "copyLegacy": false,
 "useLegacy": false
}

6. Refresh your browser to view the updated secrets engine

7. Exit and kill the containers when done with CTRL+C

API Documentation

Authentication

Requests require two headers for authenticating.

property	type	value example	required	purpose
Vault-Url	string	http://hashicorpVaultUrl:8200	Y	The URL of the HashiCorp Vault instance.
Api-Key	string	dev-only-token	Y	Token to auth with HashiCorp Vault instance.

Vault Endpoint

http://localhost:4269/vault/init

POST

This request will initialize an empty vault instance with either the "legacy" architecture or the "new" architecture. You can run this with copyLegacy set to true and useLegacy set to false to copy secrets from the legacy architecture and add them into the "new" architecture. This was used to reduce copy/pasting manually.

Vault Request Object

property	type	value example	required	purpose
copyLegacy	bool	true / false	Y	If set to true and useLegacy is set to false, this will copy legacy secrets architecture and place them into the flat architecture.
useLegacy	bool	true / false	Y	If set to true, this builds secrets using the legacy architecture.

Vault Request Struct

type VaultRequest struct {
 CopyLegacy bool      `json:"copyLegacy" validate:"required"`
 UseLegacy  bool      `json:"useLegacy" validate:"required"`
}

Example Vault Request Object

{
  "useLegacy": true,
  "copyLegacy": true
}

Vault/Secret Endpoint

http://localhost:4269/vault/secret

POST

Vault Secret Object

property	type	value example	required	purpose
secret	array of Secret	[{engine, kv:[{data, path}]}]	Y	A secret is an array of Secrets which are containers holding engines (folders), paths inside the engine, and data (key/value pairs)
engine	string	firebase	Y	Engines are top-level folders. They also dictate the type of secret that will be held. In this application, all secrets are K/V pairs.
kv	array of KV	[{data: map[string]interface{}, path: ""}]	Y	KV stands for Key Value. This is a collection of Key/Value pairs that can be inserted into the parent-engine. As Vault can only update all or none of an engine, these are tighlyt coupled.
data	map[string]interface{}	{"apiKey" : "12345678", "anotherKey" : "823oi3-sjj39848-vvdse" }	Y	Data is ingested as an object of string : string. All keys and values must be entered in quotations and separated by commas.
path	string	"userKeys/dev"	Y	The path is where the secret will be contained inside the engine provided. Paths must not start or end with a forward slash ("/"). The provided example would resolve to ENGINENAME/data/userKeys/dev

Vault Secret Struct

  type VaultSecret struct {
    Secret []Secret `json:"secret"`
  }

type Secret struct {
 Engine string `json:"engine"`
 KV     []struct {
  Data map[string]interface{} `json:"data" validate:"required"`
  Path string                 `json:"path" validate:"required"`
 } `json:"kv"`
}

Example Vault Secret Object

{
  "secret": [
    {
      "engine": "apiengine",
      "kv": [
        {
          "path": "api-test",
          "data": {
            "api_key": "myApiKey",
            "test": "another key"
          }
        }
      ]
    }
  ]
}

GET

Vault Read Object

property	type	value example	required	purpose
engine	string	firebase	Y	The KV-V2 engine from which to read a value
path	string	stripe/dev	Y	Path to the secret in the aformentioned engine
key	string	private_api_key	Y	The key for which to return a value

Vault Read Struct

type VaultRead struct {
 Engine string    `json:"engine" validate:"required"`
 Path   string    `json:"path" validate:"required"`
 Key    string    `json:"key" validate:"required"`
}

Example Vault Read Object

{
  "engine": "myfolder",
  "path": "stripe/dev",
  "key": "private_key"
}

Example Response

{
  "Success": {
    "private_key": "secretHere"
  }
}

Vault Config

Vault is based on CRUD operations and as such has decided that all data needs to be created (or updated) at once by passing in a map of string:string (more precisely, map[string]interface{}).

I wanted to package as much information together as I could so I bundled all of the data into a kv struct which holds the arrays of k/v pairs themselves and the path inside the engine where these k/v pairs should live.

Further, I needed to iterate over engines (folders in Vault-speak) and place secrets in different paths inside the same engine. Thus was born the secret struct.

types.go

type Secret struct {
 Engine string
 KV     []struct {
  Data map[string]interface{}
  Path string
 }
}

vault_config.go

var sampleSecret = []*Secret{
 {
  Engine: "my-engine",
  KV: []struct {
   Data map[string]interface{}
   Path string
  }{
   {
    Data: map[string]interface{}{
     "myKey":  "myValue",
     "myKey2": "myValue2",
    },
    Path: "my-path-1"
    },
  },
 },
}

Secrets Map

secretMap came along a while after I had built out the project. My Vault instances had many duplicates and no real organization. The secret names were also confusing/unclear and this caused even more duplicates in vault. I decided to migrate to a flattened structure. With this, I wanted to keep the old structure in-tact in case any old systems were using them and I also didn't want to have to copy-paste information by-hand.

To handle this I built the hydrateNewSecretsStruct() function. This would take the newSecrets struct and fill in the values from the vault instance and then push the hydrated newSecrets into vault, saving hours of work. The structure on this one is pretty simple as it adds an extra layer to the Secrets{}:

types.go

type secretMap struct {
 secret string
 path   string
}

This function takes the path for the given secret, and then searches the newSecrets{} for a matching key. When a matching key is found, it places the secret gathered in as the value.

Vault

Given the information above I hope that the vault.go file is self explanatory. These are all the functions necessary to authenticate with vault and then read / write secrets as necessary.

Vault Test

I wanted to make sure I could test many of these functions without needing to make any real API calls. I decided to mock many of the calls and built an interface to utilize dependency injection.

Utility

Pwgen

This was built with the help of a medium article. Initially it used a simple RAND based on unix time. That is obviously not cryptographically secure, so I implemented a change using crypto/rand. It creates a slice of runes, iterates for the length of password passed adding a rune for the provided characters per iteration. It then returns the stringified version of the rune slice.

GenerateUUID uses Google's UUID generator. This can be helpful when setting up a fresh instance and setting some random passwords.

Validate Request Fields

Using the go-playground/validator package this validates the vault request object. Errors are returned based on incompatibilities or missing properties.