feat: add generic auth (#39)

* feat: add generic auth

Adds the ability to authenticate against any normal Vault endpoint by added the `authPayload` input.

When an unrecognized method is provided, the action will attempt to hit `v1/auth/<method>/login` with the provided `authPayload and parse out the token in the response

.github/workflows/build.yml

@@ -112,6 +112,7 @@ jobs:
         VAULT_PORT: ${{ job.services.vault.ports[8200] }}
     - name: use vault action (default K/V version 2)
       uses: ./
+      id: kv-secrets
       with:
         url: http://localhost:${{ job.services.vault.ports[8200] }}
         token: testtoken
@@ -140,6 +141,8 @@ jobs:
           /cubbyhole/test zip | NAMED_CUBBYSECRET ;
     - name: verify
       run: npm run test:e2e
+      env:
+        OTHER_SECRET_OUTPUT: ${{ steps.kv-secrets.outputs.otherSecret }}
 
   publish:
     if: github.event_name	== 'push' && contains(github.ref, 'master')

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "markdown-toc.depthFrom": 2
+}

README.md

@@ -4,6 +4,25 @@ A helper action for easily pulling secrets from HashiCorp Vault™.
 
 By default, this action pulls from  [Version 2](https://www.vaultproject.io/docs/secrets/kv/kv-v2/) of the K/V Engine. See examples below for how to [use v1](#using-kv-version-1) as well as [other non-K/V engines](#other-secret-engines).
 
+<!-- TOC -->
+
+- [Example Usage](#example-usage)
+- [Authentication method](#authentication-method)
+- [Key Syntax](#key-syntax)
+    - [Simple Key](#simple-key)
+    - [Set Output Variable Name](#set-output-variable-name)
+    - [Multiple Secrets](#multiple-secrets)
+    - [Using K/V version 1](#using-kv-version-1)
+- [Custom K/V Engine Path](#custom-kv-engine-path)
+- [Other Secret Engines](#other-secret-engines)
+- [Adding Extra Headers](#adding-extra-headers)
+- [Vault Enterprise Features](#vault-enterprise-features)
+    - [Namespace](#namespace)
+- [Reference](#reference)
+- [Masking - Hiding Secrets from Logs](#masking---hiding-secrets-from-logs)
+
+<!-- /TOC -->
+
 ## Example Usage
 
 ```yaml
@@ -28,14 +47,14 @@ jobs:
 
 While most workflows will likely use a vault token, you can also use an `approle` to authenticate with vaule. You can configure which by using the `method` parameter:
 
-- **token**: (by default) you must provide a token parameter
+- **token**: (by default) you must provide a `token` parameter
 ```yaml
 ...
 with:
   url: https://vault.mycompany.com:8200
   token: ${{ secrets.VaultToken }}
 ```
-- **approle**: you must provide a roleId & secretId parameter
+- **approle**: you must provide a `roleId` & `secretId` parameter
 ```yaml
 ...
 with:
@@ -44,6 +63,14 @@ with:
   roleId: ${{ secrets.roleId }}
   secretId: ${{ secrets.secretId }}
 ```
+- **github**: you must provide the github token as `githubToken`
+```yaml
+...
+with:
+  url: https://vault.mycompany.com:8200
+  method: github
+  githubToken: ${{ secrets.GITHUB_TOKEN }}
+```
 
 ## Key Syntax
 
@@ -52,7 +79,7 @@ The `secrets` parameter is a set of multiple secret requests separated by the `;
 Each secret request is comprised of the `path` and the `key` of the desired secret, and optionally the desired Env Var output name.
 
 ```raw
-{{ Secret Path }} {{ Secret Key }} | {{ Output Environment Variable Name }}
+{{ Secret Path }} {{ Secret Key }} | {{ Output Variable Name }}
 ```
 
 ### Simple Key
@@ -64,15 +91,30 @@ with:
     secrets: ci npmToken
 ```
 
-`vault-action` will automatically normalize the given data key, and output:
+`vault-action` will automatically normalize the given secret selector key, and set the follow as environment variables for the following steps in the current job:
 
 ```bash
 NPMTOKEN=somelongtoken
 ```
 
-### Set Environment Variable Name
+You can also access the secret via ouputs:
 
-However, if you want to set it to a specific environmental variable, say `NPM_TOKEN`, you could do this instead:
+```yaml
+steps:
+    # ...
+    - name: Import Secrets
+      id: secrets
+      # Import config...
+    - name: Sensitive Operation
+      run: "my-cli --token '${{ steps.secrets.outputs.npmToken }}'"
+
+```
+
+_**Note:** If you'd like to only use outputs and disable automatic environment variables, you can set the `exportEnv` option to `false`._
+
+### Set Output Variable Name
+
+However, if you want to set it to a specific name, say `NPM_TOKEN`, you could do this instead:
 
 ```yaml
 with:
@@ -85,6 +127,17 @@ With that, `vault-action` will now use your requested name and output:
 NPM_TOKEN=somelongtoken
 ```
 
+```yaml
+steps:
+  # ...
+  - name: Import Secrets
+    id: secrets
+    # Import config...
+  - name: Sensitive Operation
+    run: "my-cli --token '${{ steps.secrets.outputs.NPM_TOKEN }}'"
+
+```
+
 ### Multiple Secrets
 
 This action can take multi-line input, so say you had your AWS keys stored in a path and wanted to retrieve both of them. You can do:
@@ -107,7 +160,7 @@ with:
     kv-version: 1
 ```
 
-### Custom K/V Engine Path
+## Custom K/V Engine Path
 
 When you enable the K/V Engine, by default it's placed at the path `secret`, so a secret named `ci` will be accessed from `secret/ci`. However, [if you enabled the secrets engine using a custom `path`](https://www.vaultproject.io/docs/commands/secrets/enable/#inlinecode--path-4), you
 can pass it as follows:
@@ -120,7 +173,7 @@ with:
 
 This way, the `ci` secret in the example above will be retrieved from `my-secrets/ci`.
 
-### Other Secret Engines
+## Other Secret Engines
 
 While this action primarily supports the K/V engine, it is possible to request secrets from other engines in Vault.
 
@@ -147,7 +200,20 @@ with:
 Resulting in:
 
 ```bash
-FOO=bar MY_KEY=zap
+FOO=bar
+MY_KEY=zap
+```
+
+```yaml
+steps:
+  # ...
+  - name: Import Secrets
+    id: secrets
+    # Import config...
+  - name: Sensitive Operation
+    run: "my-cli --token '${{ steps.secrets.outputs.foo }}'"
+  - name: Another Sensitive Operation
+    run: "my-cli --token '${{ steps.secrets.outputs.MY_KEY }}'"
 ```
 
 Secrets pulled from the same `Secret Path` are cached by default. So if you, for example, are using the `aws` engine and retrieve a key, only a single key for a given path is returned.
@@ -165,6 +231,22 @@ would work fine.
 
 NOTE: The `Secret Key` is pulled from the `data` property of the response.
 
+## Adding Extra Headers
+
+If you ever need to add extra headers to the vault request, say if you need to authenticate with a firewall, all you need to do is set `extraHeaders`:
+
+```yaml
+with:
+    secrets: |
+        ci/aws accessKey | AWS_ACCESS_KEY_ID ;
+        ci/aws secretKey | AWS_SECRET_ACCESS_KEY
+    extraHeaders: |
+      X-Secure-Id: ${{ secrets.SECURE_ID }}
+      X-Secure-Secret: ${{ secrets.SECURE_SECRET }}
+```
+
+This will automatically add the `x-secure-id` and `x-secure-secret` headers to every request to vault.
+
 ## Vault Enterprise Features
 
 ### Namespace
@@ -187,6 +269,26 @@ steps:
             ci npm_token
 ```
 
-## Masking
+## Reference
 
-This action uses Github Action's built in masking, so all variables will automatically be masked if printed to the console or to logs.
+Here is all the inputs available through `with`:
+
+| Input          | Description                                                                                                                                          | Default | Required |
+| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | ------- | -------- |
+| `url`          | The URL for the vault endpoint                                                                                                                       |         | ✔        |
+| `secrets`      | A semicolon-separated list of secrets to retrieve. These will automatically be converted to environmental variable keys. See README for more details |         | ✔        |
+| `namespace`    | The Vault namespace from which to query secrets. Vault Enterprise only, unset by default                                                             |         |          |
+| `path`         | The path of a non-default K/V engine                                                                                                                 |         |          |
+| `kv-version`   | The version of the K/V engine to use.                                                                                                                | `2`     |          |
+| `method`       | The method to use to authenticate with Vault.                                                                                                        | `token` |          |
+| `token`        | The Vault Token to be used to authenticate with Vault                                                                                                |         |          |
+| `roleId`       | The Role Id for App Role authentication                                                                                                              |         |          |
+| `secretId`     | The Secret Id for App Role authentication                                                                                                            |         |          |
+| `githubToken`  | The Github Token to be used to authenticate with Vault                                                                                               |         |          |
+| `extraHeaders` | A string of newline separated extra headers to include on every request.                                                                             |         |          |
+| `exportEnv`    | Whether or not export secrets as environment variables.                                                                                              | `true`  |          |
+
+## Masking - Hiding Secrets from Logs
+
+This action uses GitHub Action's built-in masking, so all variables will automatically be masked (aka hidden) if printed to the console or to logs.
+**This only obscures secrets from output logs.** If someone has the ability to edit your workflows, then they are able to read and therefore write secrets to somewhere else just like normal GitHub Secrets.

action.yml

@@ -1,18 +1,48 @@
 name: 'Vault Secrets'
-description: 'A Github Action that allows you to consume the v2 K/V backend of HashiCorp Vault as secure environment variables'
+description: 'A Github Action that allows you to consume the v2 K/V backend of HashiCorp Vault™ as secure environment variables'
 inputs:
   url:
     description: 'The URL for the vault endpoint'
     required: true
-  token:
-    description: 'The Vault Token to be used to authenticate with Vault'
-    required: true
   secrets:
     description: 'A semicolon-separated list of secrets to retrieve. These will automatically be converted to environmental variable keys. See README for more details'
     required: true
   namespace:
     description: 'The Vault namespace from which to query secrets. Vault Enterprise only, unset by default'
     required: false
+  path:
+    description: 'The path of a non-default K/V engine'
+    required: false
+  kv-version:
+    description: 'The version of the K/V engine to use.'
+    default: '2'
+    required: false
+  method:
+    description: 'The method to use to authenticate with Vault.'
+    default: 'token'
+    required: false
+  token:
+    description: 'The Vault Token to be used to authenticate with Vault'
+    required: false
+  roleId:
+    description: 'The Role Id for App Role authentication'
+    required: false
+  secretId:
+    description: 'The Secret Id for App Role authentication'
+    required: false
+  githubToken:
+    description: 'The Github Token to be used to authenticate with Vault'
+    required: false
+  authPayload:
+    description: 'The JSON payload to be sent to Vault when using a custom authentication method.'
+    required: false
+  extraHeaders:
+    description: 'A string of newline separated extra headers to include on every request.'
+    required: false
+  exportEnv:
+    description: 'Whether or not export secrets as environment variables.'
+    default: 'true'
+    required: false
 runs:
   using: 'node12'
   main: 'dist/index.js'

integrationTests/basic/integration.test.js

@@ -5,7 +5,7 @@ const core = require('@actions/core');
 const got = require('got');
 const { when } = require('jest-when');
 
-const { exportSecrets } = require('../../action');
+const { exportSecrets } = require('../../src/action');
 
 const vaultUrl = `http://${process.env.VAULT_HOST || 'localhost'}:${process.env.VAULT_PORT || '8200'}`;
 

integrationTests/e2e/e2e.test.js

@@ -3,6 +3,7 @@ describe('e2e', () => {
         expect(process.env.SECRET).toBe("SUPERSECRET");
         expect(process.env.NAMED_SECRET).toBe("SUPERSECRET");
         expect(process.env.OTHERSECRET).toBe("OTHERSUPERSECRET");
+        expect(process.env.OTHER_SECRET_OUTPUT).toBe("OTHERSUPERSECRET");
         expect(process.env.ALTSECRET).toBe("CUSTOMSECRET");
         expect(process.env.NAMED_ALTSECRET).toBe("CUSTOMSECRET");
         expect(process.env.OTHERALTSECRET).toBe("OTHERCUSTOMSECRET");

integrationTests/enterprise/enterprise.test.js

@@ -5,7 +5,7 @@ const core = require('@actions/core');
 const got = require('got');
 const { when } = require('jest-when');
 
-const { exportSecrets } = require('../../action');
+const { exportSecrets } = require('../../src/action');
 
 const vaultUrl = `http://${process.env.VAULT_HOST || 'localhost'}:${process.env.VAULT_PORT || '8201'}`;
 
@@ -212,7 +212,7 @@ describe('authenticate with approle', () => {
         jest.resetAllMocks();
 
         when(core.getInput)
-            .calledWith('method')
+            .calledWith('method', expect.anything())
             .mockReturnValueOnce('approle');
         when(core.getInput)
             .calledWith('roleId')

package.json

@@ -4,7 +4,7 @@
     "description": "A Github Action that allows you to consume vault secrets as secure environment variables.",
     "main": "dist/index.js",
     "scripts": {
-        "build": "ncc build index.js -o dist",
+        "build": "ncc build src/index.js -o dist",
         "test": "jest",
         "test:integration:basic": "jest -c integrationTests/basic/jest.config.js",
         "test:integration:enterprise": "jest -c integrationTests/enterprise/jest.config.js",
@@ -38,14 +38,15 @@
     },
     "homepage": "https://github.com/RichiCoder1/vault-action#readme",
     "dependencies": {
-        "@actions/core": "^1.2.2",
-        "got": "^10.2.2"
+        "got": "^10.2.2",
+        "@actions/core": "^1.2.3"
     },
     "devDependencies": {
-        "@types/jest": "^24.0.18",
-        "@zeit/ncc": "^0.21.1",
+        "@types/got": "^9.6.9",
+        "@types/jest": "^25.1.3",
+        "@zeit/ncc": "^0.22.0",
         "jest": "^25.1.0",
         "jest-when": "^2.7.0",
-        "semantic-release": "^15.13.24"
+        "semantic-release": "^17.0.4"
     }
 }

src/action.js

@@ -1,53 +1,45 @@
+// @ts-check
 const core = require('@actions/core');
 const command = require('@actions/core/lib/command');
-const got = require('got');
+const got = require('got').default;
+const { retrieveToken } = require('./auth');
 
-const AUTH_METHODS = ['approle', 'token'];
+const AUTH_METHODS = ['approle', 'token', 'github'];
 const VALID_KV_VERSION = [-1, 1, 2];
 
 async function exportSecrets() {
     const vaultUrl = core.getInput('url', { required: true });
     const vaultNamespace = core.getInput('namespace', { required: false });
+    const extraHeaders = parseHeadersInput('extraHeaders', { required: false });
+    const exportEnv = core.getInput('exportEnv', { required: false }) != 'false';
 
     let enginePath = core.getInput('path', { required: false });
+    /** @type {number | string} */
     let kvVersion = core.getInput('kv-version', { required: false });
 
     const secretsInput = core.getInput('secrets', { required: true });
     const secretRequests = parseSecretsInput(secretsInput);
 
-    const vaultMethod = core.getInput('method', { required: false }) || 'token';
+    const vaultMethod = (core.getInput('method', { required: false }) || 'token').toLowerCase();
     if (!AUTH_METHODS.includes(vaultMethod)) {
         throw Error(`Sorry, the authentication method ${vaultMethod} is not currently supported.`);
     }
 
-    let vaultToken = null;
-    switch (vaultMethod) {
-        case 'approle':
-            const vaultRoleId = core.getInput('roleId', { required: true });
-            const vaultSecretId = core.getInput('secretId', { required: true });
-            core.debug('Try to retrieve Vault Token from approle');
-            var options = {
-                headers: {},
-                json: { role_id: vaultRoleId, secret_id: vaultSecretId },
-                responseType: 'json'
-            };
+    const defaultOptions = {
+        prefixUrl: vaultUrl,
+        headers: {}
+    }
+
+    for (const [headerName, headerValue] of extraHeaders) {
+        defaultOptions.headers[headerName] = headerValue;
+    }
 
     if (vaultNamespace != null) {
-                options.headers["X-Vault-Namespace"] = vaultNamespace;
+        defaultOptions.headers["X-Vault-Namespace"] = vaultNamespace;
     }
 
-            const result = await got.post(`${vaultUrl}/v1/auth/approle/login`, options);
-            if (result && result.body && result.body.auth && result.body.auth.client_token) {
-                vaultToken = result.body.auth.client_token;
-                core.debug('✔ Vault Token has retrieved from approle');
-            } else {
-                throw Error(`No token was retrieved with the role_id and secret_id provided.`);
-            }
-            break;
-        default:
-            vaultToken = core.getInput('token', { required: true });
-            break;
-    }
+    const client = got.extend(defaultOptions);
+    const vaultToken = await retrieveToken(vaultMethod, client);
 
     if (!enginePath) {
         enginePath = 'secret';
@@ -64,18 +56,22 @@ async function exportSecrets() {
 
     const responseCache = new Map();
     for (const secretRequest of secretRequests) {
-        const { secretPath, outputName, secretSelector, isJSONPath } = secretRequest;
+        const { secretPath, outputVarName, envVarName, secretSelector, isJSONPath } = secretRequest;
         const requestOptions = {
             headers: {
                 'X-Vault-Token': vaultToken
             },
         };
 
+        for (const [headerName, headerValue] of extraHeaders) {
+            requestOptions.headers[headerName] = headerValue;
+        }
+
         if (vaultNamespace != null) {
             requestOptions.headers["X-Vault-Namespace"] = vaultNamespace;
         }
 
-        let requestPath = `${vaultUrl}/v1`;
+        let requestPath = `v1`;
         const kvRequest = !secretPath.startsWith('/')
         if (!kvRequest) {
             requestPath += secretPath;
@@ -90,7 +86,7 @@ async function exportSecrets() {
             body = responseCache.get(requestPath);
             core.debug('ℹ using cached response');
         } else {
-            const result = await got(requestPath, requestOptions);
+            const result = await client.get(requestPath, requestOptions);
             body = result.body;
             responseCache.set(requestPath, body);
         }
@@ -98,13 +94,24 @@ async function exportSecrets() {
         let dataDepth = isJSONPath === true ? 0 : kvRequest === false ? 1 : kvVersion;
 
         const secretData = getResponseData(body, dataDepth);
-        const value = selectData(secretData, secretSelector);
+        const value = selectData(secretData, secretSelector, isJSONPath);
         command.issue('add-mask', value);
-        core.exportVariable(outputName, `${value}`);
-        core.debug(`✔ ${secretPath} => ${outputName}`);
+        if (exportEnv) {
+            core.exportVariable(envVarName, `${value}`);
+        }
+        core.setOutput(outputVarName, `${value}`);
+        core.debug(`✔ ${secretPath} => outputs.${outputVarName}${exportEnv ? ` | env.${envVarName}` : ''}`);
     }
 };
 
+/** @typedef {Object} SecretRequest 
+ * @property {string} secretPath
+ * @property {string} envVarName
+ * @property {string} outputVarName
+ * @property {string} secretSelector
+ * @property {boolean} isJSONPath
+*/
+
 /**
  * Parses a secrets input string into key paths and their resulting environment variable name.
  * @param {string} secretsInput
@@ -116,18 +123,18 @@ function parseSecretsInput(secretsInput) {
         .map(key => key.trim())
         .filter(key => key.length !== 0);
 
-    /** @type {{ secretPath: string; outputName: string; dataKey: string; }[]} */
+    /** @type {SecretRequest[]} */
     const output = [];
     for (const secret of secrets) {
         let path = secret;
-        let outputName = null;
+        let outputVarName = null;
 
         const renameSigilIndex = secret.lastIndexOf('|');
         if (renameSigilIndex > -1) {
             path = secret.substring(0, renameSigilIndex).trim();
-            outputName = secret.substring(renameSigilIndex + 1).trim();
+            outputVarName = secret.substring(renameSigilIndex + 1).trim();
 
-            if (outputName.length < 1) {
+            if (outputVarName.length < 1) {
                 throw Error(`You must provide a value when mapping a secret to a name. Input: "${secret}"`);
             }
         }
@@ -138,21 +145,29 @@ function parseSecretsInput(secretsInput) {
             .filter(part => part.length !== 0);
 
         if (pathParts.length !== 2) {
-            throw Error(`You must provide a valid path and key. Input: "${secret}"`)
+            throw Error(`You must provide a valid path and key. Input: "${secret}"`);
         }
 
         const [secretPath, secretSelector] = pathParts;
 
-        // If we're not using a mapped name, normalize the key path into a variable name.
-        if (!outputName) {
-            outputName = normalizeOutputKey(secretSelector);
+        const isJSONPath = secretSelector.includes('.');
+
+        if (isJSONPath && !outputVarName) {
+            throw Error(`You must provide a name for the output key when using json selectors. Input: "${secret}"`);
+        }
+
+        let envVarName = outputVarName;
+        if (!outputVarName) {
+            outputVarName = secretSelector;
+            envVarName = normalizeOutputKey(outputVarName);
         }
 
         output.push({
             secretPath,
-            outputName,
+            envVarName,
+            outputVarName,
             secretSelector,
-            isJSONPath: secretSelector.startsWith('$')
+            isJSONPath
         });
     }
     return output;
@@ -161,7 +176,7 @@ function parseSecretsInput(secretsInput) {
 /**
  * Parses a JSON response and returns the secret data
  * @param {string} responseBody
- * @param {number} kvVersion
+ * @param {number} dataLevel
  */
 function getResponseData(responseBody, dataLevel) {
     let secretData = JSON.parse(responseBody);
@@ -193,16 +208,35 @@ function normalizeOutputKey(dataKey) {
     return dataKey.replace('/', '__').replace(/[^\w-]/, '').toUpperCase();
 }
 
-function parseBoolInput(input) {
-    if (input === null || input === undefined || input.trim() === '') {
-        return null;
+/**
+ * @param {string} inputKey
+ * @param {any} inputOptions
+ */
+function parseHeadersInput(inputKey, inputOptions) {
+    /** @type {string}*/
+    const rawHeadersString = core.getInput(inputKey, inputOptions) || '';
+    const headerStrings = rawHeadersString
+        .split('\n')
+        .map(line => line.trim())
+        .filter(line => line !== '');
+    return headerStrings
+        .reduce((map, line) => {
+            const seperator = line.indexOf(':');
+            const key = line.substring(0, seperator).trim().toLowerCase();
+            const value = line.substring(seperator + 1).trim();
+            if (map.has(key)) {
+                map.set(key, [map.get(key), value].join(', '));
+            } else {
+                map.set(key, value);
             }
-    return Boolean(input);
+            return map;
+        }, new Map());
 }
 
 module.exports = {
     exportSecrets,
     parseSecretsInput,
     parseResponse: getResponseData,
-    normalizeOutputKey
+    normalizeOutputKey,
+    parseHeadersInput
 };

src/action.test.js

@@ -7,7 +7,8 @@ const got = require('got');
 const {
     exportSecrets,
     parseSecretsInput,
-    parseResponse
+    parseResponse,
+    parseHeadersInput
 } = require('./action');
 
 const { when } = require('jest-when');
@@ -18,7 +19,8 @@ describe('parseSecretsInput', () => {
         expect(output).toContainEqual({
             secretPath: 'test',
             secretSelector: 'key',
-            outputName: 'KEY',
+            outputVarName: 'key',
+            envVarName: 'KEY',
             isJSONPath: false
         });
     });
@@ -27,7 +29,8 @@ describe('parseSecretsInput', () => {
         const output = parseSecretsInput('test key|testName');
         expect(output).toHaveLength(1);
         expect(output[0]).toMatchObject({
-            outputName: 'testName',
+            outputVarName: 'testName',
+            envVarName: 'testName',
         });
     });
 
@@ -58,10 +61,12 @@ describe('parseSecretsInput', () => {
 
         expect(output).toHaveLength(2);
         expect(output[0]).toMatchObject({
-            outputName: 'A',
+            outputVarName: 'a',
+            envVarName: 'A',
         });
         expect(output[1]).toMatchObject({
-            outputName: 'secondName',
+            outputVarName: 'secondName',
+            envVarName: 'secondName'
         });
     });
 
@@ -76,14 +81,56 @@ describe('parseSecretsInput', () => {
             secretPath: 'first',
         });
         expect(output[1]).toMatchObject({
-            outputName: 'B',
+            outputVarName: 'b',
+            envVarName: 'B'
         });
         expect(output[2]).toMatchObject({
-            outputName: 'SOME_C',
+            outputVarName: 'SOME_C',
+            envVarName: 'SOME_C',
         });
     })
 });
 
+describe('parseHeaders', () => {
+    it('parses simple header', () => {
+        when(core.getInput)
+            .calledWith('extraHeaders')
+            .mockReturnValueOnce('TEST: 1');
+        const result = parseHeadersInput('extraHeaders');
+        expect(Array.from(result)).toContainEqual(['test', '1']);
+    });
+
+    it('parses simple header with whitespace', () => {
+        when(core.getInput)
+            .calledWith('extraHeaders')
+            .mockReturnValueOnce(`
+            TEST: 1
+            `);
+        const result = parseHeadersInput('extraHeaders');
+        expect(Array.from(result)).toContainEqual(['test', '1']);
+    });
+
+    it('parses multiple headers', () => {
+        when(core.getInput)
+            .calledWith('extraHeaders')
+            .mockReturnValueOnce(`
+            TEST: 1
+            FOO: bAr
+            `);
+        const result = parseHeadersInput('extraHeaders');
+        expect(Array.from(result)).toContainEqual(['test', '1']);
+        expect(Array.from(result)).toContainEqual(['foo', 'bAr']);
+    });
+
+    it('parses null response', () => {
+        when(core.getInput)
+            .calledWith('extraHeaders')
+            .mockReturnValueOnce(null);
+        const result = parseHeadersInput('extraHeaders');
+        expect(Array.from(result)).toHaveLength(0);
+    });
+})
+
 describe('parseResponse', () => {
     // https://www.vaultproject.io/api/secret/kv/kv-v1.html#sample-response
     it('parses K/V version 1 response', () => {
@@ -142,22 +189,24 @@ describe('exportSecrets', () => {
             .mockReturnValueOnce(version);
     }
 
+    function mockExtraHeaders(headerString) {
+        when(core.getInput)
+            .calledWith('extraHeaders')
+            .mockReturnValueOnce(headerString);
+    }
+
     function mockVaultData(data, version='2') {
         switch(version) {
             case '1':
-                got.mockResolvedValue({
-                    body: JSON.stringify({
-                        data
-                    })
+                got.extend.mockReturnValue({
+                    get: async () => ({ body: JSON.stringify({ data }) })
                 });
             break;
             case '2':
-                got.mockResolvedValue({
-                    body: JSON.stringify({
-                        data: {
+                got.extend.mockReturnValue({
+                    get: async () => ({ body: JSON.stringify({ data: {
                         data
-                        }
-                    })
+                    } }) })
                 });
             break;
         }
@@ -172,6 +221,7 @@ describe('exportSecrets', () => {
         await exportSecrets();
 
         expect(core.exportVariable).toBeCalledWith('KEY', '1');
+        expect(core.setOutput).toBeCalledWith('key', '1');
     });
 
     it('mapped secret retrieval', async () => {
@@ -183,11 +233,29 @@ describe('exportSecrets', () => {
         await exportSecrets();
 
         expect(core.exportVariable).toBeCalledWith('TEST_NAME', '1');
+        expect(core.setOutput).toBeCalledWith('TEST_NAME', '1');
     });
 
     it('simple secret retrieval from K/V v1', async () => {
         const version = '1';
 
+        mockInput('test key');
+        mockExtraHeaders(`
+        TEST: 1
+        `);
+        mockVaultData({
+            key: 1
+        });
+
+        await exportSecrets();
+
+        expect(core.exportVariable).toBeCalledWith('KEY', '1');
+        expect(core.setOutput).toBeCalledWith('key', '1');
+    });
+
+    it('simple secret retrieval with extra headers', async () => {
+        const version = '1';
+
         mockInput('test key');
         mockVersion(version);
         mockVaultData({
@@ -197,5 +265,6 @@ describe('exportSecrets', () => {
         await exportSecrets();
 
         expect(core.exportVariable).toBeCalledWith('KEY', '1');
+        expect(core.setOutput).toBeCalledWith('key', '1');
     });
 });

src/auth.js

@@ -0,0 +1,81 @@
+// @ts-check
+const core = require('@actions/core');
+
+/***
+ * Authenticate with Vault and retrieve a Vault token that can be used for requests.
+ * @param {string} method
+ * @param {import('got').Got} client
+ */
+async function retrieveToken(method, client) {
+    switch (method) {
+        case 'approle': {
+            const vaultRoleId = core.getInput('roleId', { required: true });
+            const vaultSecretId = core.getInput('secretId', { required: true });
+            return await getClientToken(client, method, { role_id: vaultRoleId, secret_id: vaultSecretId });
+        }
+        case 'github': {
+            const githubToken = core.getInput('githubToken', { required: true });
+            return await getClientToken(client, method, { token: githubToken });
+        }
+        default: {
+            if (!method || method === 'token') {
+                return core.getInput('token', { required: true });
+            } else {
+                /** @type {string} */
+                const payload = core.getInput('authPayload', { required: true });
+                if (!payload) {
+                    throw Error('When using a custom authentication method, you must provide the payload');
+                }
+                return await getClientToken(client, method, JSON.parse(payload.trim()));
+            }
+        }
+    }
+}
+
+/***
+ * Call the appropriate login endpoint and parse out the token in the response.
+ * @param {import('got').Got} client
+ * @param {string} method
+ * @param {any} payload
+ */
+async function getClientToken(client, method, payload) {
+    /** @type {'json'} */
+    const responseType = 'json';
+    var options = {
+        json: payload,
+        responseType,
+    };
+
+    core.debug(`Retrieving Vault Token from v1/auth/${method}/login endpoint`);
+
+    /** @type {import('got').Response<VaultLoginResponse>} */
+    const response = await client.post(`v1/auth/${method}/login`, options);
+    if (response && response.body && response.body.auth && response.body.auth.client_token) {
+        core.debug('✔ Vault Token successfully retrieved');
+
+        core.startGroup('Token Info');
+        core.debug(`Operating under policies: ${JSON.stringify(response.body.auth.policies)}`);
+        core.debug(`Token Metadata: ${JSON.stringify(response.body.auth.metadata)}`);
+        core.endGroup();
+
+        return response.body.auth.client_token;
+    } else {
+        throw Error(`Unable to retrieve token from ${method}'s login endpoint.`);
+    }
+}
+
+/***
+ * @typedef {Object} VaultLoginResponse
+ * @property {{
+ *  client_token: string;
+ *  accessor: string;
+ *  policies: string[];
+ *  metadata: unknown;
+ *  lease_duration: number;
+ *  renewable: boolean;
+ * }} auth
+ */
+
+module.exports = {
+    retrieveToken,
+};

tsconfig.json

@@ -0,0 +1,12 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "target": "es2019",
+        "moduleResolution": "node",
+        "allowJs": true,
+        "noEmit": true
+    },
+    "exclude": [
+        "node_modules"
+    ]
+}