Add configuration option for the metric server interface (#25)

Add a configuration option `interface` to allow configuring where the
HTTP metric server should bind to.

README.md

@@ -134,6 +134,11 @@ Once *Prometheus* is restarted, metrics with the `homebridge_` prefix should sta
       // TCP port where the Prometheus metrics server listens. Default: 36123
       "port": number,
 
+      // Interface where the Prometheus metrics server listens. Default: "::" which means "any interface".
+      // Can be an IP, a hostname, "0.0.0.0" for all IPv4 interfaces, "::1" for all IPv6 interfaces.
+      // Default is "::" which means any interface
+      "interface": string,
+
       // How frequently the services should be rediscovered (in seconds). Default: 60
       "refresh_interval": number,
 

config.schema.json

@@ -26,12 +26,18 @@
                 "default": "homebridge"
             },
             "port": {
-                "title": "Probe server port",
+                "title": "Metrics server port",
-                "description": "TCP port for the prometheus probe server to listen to",
+                "description": "TCP port where the Prometheus metrics server listens",
                 "type": "integer",
                 "required": false,
                 "default": 36123
             },
+            "interface": {
+                "title": "Metrics server interface",
+                "description": "Interface where the Prometheus metrics server listens. Can be an IP, a hostname, \"0.0.0.0\" for all IPv4 interfaces, \"::1\" for all IPv6 interfaces. Default is \"::\" which means \"any interface\"",
+                "type": "string",
+                "default": "::"
+            },
             "refresh_interval": {
                 "title": "Service refresh interval",
                 "description": "Discover new services every <interval> seconds",
@@ -54,17 +60,20 @@
                 "default": 20
             },
             "tls_cert_file": {
+                "title": "TLS cert file",
                 "description": "Path to TLS certificate file (in PEM format)",
                 "type": "string",
                 "required": false
             },
             "tls_key_file": {
+                "title": "TLS key file",
                 "description": "Path to TLS key file",
                 "type": "string",
                 "required": false
             },
             "basic_auth": {
-                "description": "Usernames and passwords for basic auth. Key is the username, value is the password. Password must be encoded with bcrypt",
+                "title": "Basic auth username/password pairs",
+                "description": "Usernames and passwords for basic auth. Object key is the username, object value is the password. Password must be encoded with bcrypt. Example: {\"joanna\": \"$2a$12$5/mmmRB28wg9yzaXhee5Iupq3UrFr/qMgAe9LvAxGoY5jLcfVGTUq\"}",
                 "type": "object",
                 "additionalProperties": { "type": "string" },
                 "required": false

src/adapters/http/api.ts

@@ -15,7 +15,10 @@ export interface HttpServerController {
 
 export type HttpAdapter = (config: HttpServer) => Promise<HttpServerController>
 
-export type HttpConfig = Pick<Config, 'debug' | 'port' | 'prefix' | 'basic_auth' | 'tls_cert_file' | 'tls_key_file'>
+export type HttpConfig = Pick<
+    Config,
+    'debug' | 'port' | 'interface' | 'prefix' | 'basic_auth' | 'tls_cert_file' | 'tls_key_file'
+>
 
 export interface HttpServer {
     log?: Logger

src/adapters/http/fastify.ts

@@ -97,7 +97,7 @@ export const fastifyServe: HttpAdapter = async (server: HttpServer) => {
         adaptResponseToReply(server.onMetrics(), reply)
     })
 
-    await listen(fastify, server.config.port, '::')
+    await listen(fastify, server.config.port, server.config.interface)
 
     return {
         shutdown() {

src/generated/config_boundary.ts

@@ -6,7 +6,13 @@ export const ConfigBoundary = z.object({
     pin: z.string().regex(new RegExp('^\\d{3}-\\d{2}-\\d{3}$')).describe('Homebridge PIN for service authentication'),
     debug: z.boolean().default(false),
     prefix: z.string().default('homebridge'),
-    port: z.number().int().describe('TCP port for the prometheus probe server to listen to').default(36123),
+    port: z.number().int().describe('TCP port where the Prometheus metrics server listens').default(36123),
+    interface: z
+        .string()
+        .describe(
+            'Interface where the Prometheus metrics server listens. Can be an IP, a hostname, "0.0.0.0" for all IPv4 interfaces, "::1" for all IPv6 interfaces. Default is "::" which means "any interface"',
+        )
+        .default('::'),
     refresh_interval: z.number().int().describe('Discover new services every <interval> seconds').default(60),
     request_timeout: z
         .number()
@@ -23,7 +29,7 @@ export const ConfigBoundary = z.object({
     basic_auth: z
         .record(z.string())
         .describe(
-            'Usernames and passwords for basic auth. Key is the username, value is the password. Password must be encoded with bcrypt',
+            'Usernames and passwords for basic auth. Object key is the username, object value is the password. Password must be encoded with bcrypt. Example: {"joanna": "$2a$12$5/mmmRB28wg9yzaXhee5Iupq3UrFr/qMgAe9LvAxGoY5jLcfVGTUq"}',
         )
         .optional(),
 })

tests/adapters/http/fastify.test.ts

@@ -17,6 +17,7 @@ function createTestServerWithBasicAuth(basicAuth: Record<string, string>): { htt
     const http = createServer()
     const prometheus = new TestablePrometheusServer({
         port: 0,
+        interface: 'localhost',
         debug: false,
         prefix: 'homebridge',
         basic_auth: basicAuth,