Auth: Support reading username/password from files

Author: TheColorman

README.md

@@ -81,7 +81,9 @@ List of environment variables for more customization:
 | ENABLE_AUTHENTICATION                | true                                                                                                              | `false` by default.                                                                                                                                                                          |
 | AUTHENTICATION_REALM                 | MyRealm                                                                                                           | Use this env if ENABLE_AUTHENTICATION is `true`.                                                                                                                                             |
 | USERNAME                             | admin                                                                                                             | Use this env if ENABLE_AUTHENTICATION is `true`.                                                                                                                                             |
+| USERNAME_FILE                        | /run/secrets/username                                                                                             | Alternative to `USERNAME`.                                                                                                                                                                   |
 | PASSWORD                             | supersecret                                                                                                       | Use this env if ENABLE_AUTHENTICATION is `true`.                                                                                                                                             |
+| PASSWORD_FILE                        | /run/secrets/password                                                                                             | Alternative to `PASSWORD`.                                                                                                                                                                   |
 | ENABLE_HTTPS                         | true                                                                                                              | `false` by default.                                                                                                                                                                          |
 | LEGO_PATH                            | /lego-files                                                                                                       | Use this env if ENABLE_HTTPS is `true`. Lego is used to create the SSL certificates. Create a named volume for this path to avoid the creation of a new certificate on each run.             |
 | HTTPS_HOSTNAME                       | swarm-dashboard.example.com                                                                                       | Use this env if ENABLE_HTTPS is `true`.                                                                                                                                                      |

compose.yml

@@ -19,7 +19,9 @@ services:
       # ENABLE_AUTHENTICATION: "true"
       # AUTHENTICATION_REALM: "KuW2i9GdLIkql"
       # USERNAME: "admin"
+      # USERNAME_FILE: "/run/secrets/username"
       # PASSWORD: "supersecret"
+      # PASSWORD_FILE: "/run/secrets/password"
       # ENABLE_HTTPS: "false"
       # ENABLE_HTTPS: "true"
       # HTTPS_HOSTNAME: "example.com"
@@ -40,4 +42,4 @@ services:
           - node.role == manager
 
 volumes:
-  lego-files:
+  lego-files:

server/index.js

@@ -15,8 +15,12 @@ import moment from 'moment';
 const port = process.env.PORT || 8080;
 const realm = process.env.AUTHENTICATION_REALM || "KuW2i9GdLIkql";
 const enableAuthentication = process.env.ENABLE_AUTHENTICATION === "true"
-const username = process.env.USERNAME || "admin";
-const password = process.env.PASSWORD || "supersecret";
+const username = process.env.USERNAME_FILE
+  ? readFileSync(process.env.USERNAME_FILE, 'utf-8')
+  : process.env.USERNAME || "admin";
+const password = process.env.PASSWORD_FILE
+  ? readFileSync(process.env.PASSWORD_FILE, 'utf-8')
+  : process.env.PASSWORD || "supersecret";
 const enableHTTPS = process.env.ENABLE_HTTPS === "true";
 const legoPath = process.env.LEGO_PATH || "/lego-files";
 const httpsHostname = process.env.HTTPS_HOSTNAME;