Extract prometheus server

.eslintrc.js

@@ -7,6 +7,7 @@ module.exports = {
         'prettier/prettier': 'warn',
         '@typescript-eslint/explicit-module-boundary-types': 'error',
         'prefer-arrow-callback': 'error',
+        'sort-imports': 'warn',
     },
     overrides: [
         {

TODOs

@@ -1 +1 @@
-- Extract HttpServer
+- Prefix via configuration

src/adapters/discovery/api.ts

@@ -1,9 +1,9 @@
-import type { Device } from '../boundaries'
+import type { Device } from '../../boundaries'
 import { Logger } from 'homebridge'
 
 type Pin = string
 
-export type HapConfig = {
+export interface HapConfig {
     pin: Pin
     refreshInterval: number
     discoveryTimeout: number

src/adapters/discovery/hap_node_js_client.ts

@@ -1,13 +1,13 @@
 import type { HapDiscover } from './api'
 import { HAPNodeJSClient } from 'hap-node-client'
 
-import { Device, DeviceBoundary } from '../boundaries'
+import { Device, DeviceBoundary } from '../../boundaries'
 import { Array, Unknown } from 'runtypes'
 import { Logger } from 'homebridge'
 
 const MaybeDevices = Array(Unknown)
 
-type HapConfig = {
+interface HapConfig {
     debug: boolean
     refresh: number
     timeout: number

src/adapters/http/api.ts

@@ -0,0 +1,13 @@
+import { HttpServer } from '../../http'
+
+export interface HttpResponse {
+    statusCode?: number
+    body?: string
+    headers?: Record<string, string>
+}
+
+export interface HttpServerController {
+    shutdown(): void
+}
+
+export type HttpAdapter = (config: HttpServer) => Promise<HttpServerController>

src/adapters/http/fastify.ts

@@ -0,0 +1,52 @@
+import Fastify, { FastifyReply, FastifyRequest, HookHandlerDoneFunction } from 'fastify'
+import { HttpAdapter, HttpResponse } from './api'
+import { HttpServer } from '../../http'
+
+function adaptResponseToReply(response: HttpResponse, reply: FastifyReply): void {
+    if (response.statusCode) {
+        void reply.code(response.statusCode)
+    }
+    if (response.body) {
+        void reply.send(response.body)
+    }
+
+    if (response.headers) {
+        void reply.headers(response.headers)
+    }
+}
+
+export const serve: HttpAdapter = async (server: HttpServer) => {
+    const fastify = Fastify({
+        logger: server.debug,
+    })
+
+    fastify.addHook('onRequest', (request: FastifyRequest, reply: FastifyReply, next: HookHandlerDoneFunction) => {
+        const response = server.onRequest()
+
+        if (response) {
+            adaptResponseToReply(response, reply)
+        }
+
+        next()
+    })
+
+    fastify.setErrorHandler(async (error, request: FastifyRequest, reply: FastifyReply) => {
+        adaptResponseToReply(server.onError(error), reply)
+    })
+
+    fastify.setNotFoundHandler(async (request: FastifyRequest, reply: FastifyReply) => {
+        adaptResponseToReply(server.onNotFound(), reply)
+    })
+
+    fastify.get('/metrics', async (request: FastifyRequest, reply: FastifyReply) => {
+        adaptResponseToReply(server.onMetrics(), reply)
+    })
+
+    await fastify.listen({ port: server.port, host: '::' })
+
+    return {
+        shutdown() {
+            void fastify.close()
+        },
+    }
+}

src/boundaries.ts

@@ -1,4 +1,4 @@
-import { Number, String, Literal, Array, Record, Union, Static, Optional, Intersect } from 'runtypes'
+import { Array, Intersect, Literal, Number, Optional, Record, Static, String, Union } from 'runtypes'
 
 export const NUMBER_TYPES = ['float', 'int', 'uint8', 'uint16', 'uint32', 'uint64'] as const
 const NumberTypesLiterals = NUMBER_TYPES.map(Literal)

src/http.ts

@@ -0,0 +1,14 @@
+import { HttpResponse } from './adapters/http/api'
+import { Metric } from './metrics'
+import { Logger } from 'homebridge'
+
+export interface HttpServer {
+    port: number
+    debug: boolean
+    log: Logger
+    onRequest(): HttpResponse | undefined
+    onMetrics(): HttpResponse
+    onNotFound(): HttpResponse
+    onError(error: unknown): HttpResponse
+    updateMetrics(metrics: Metric[]): void
+}

src/http/api.ts

@@ -1,22 +0,0 @@
-import { Logger } from 'homebridge'
-
-export type HttpResponse = {
-    statusCode: number
-    body: string
-    headers: Record<string, string>
-}
-
-export type HttpServerConfig = {
-    port: number
-    requestInterceptor: () => HttpResponse | undefined
-    metricsController: () => HttpResponse
-    notFoundController: () => HttpResponse
-    errorController: (error: unknown) => HttpResponse
-    logger: Logger
-}
-
-export type HttpServerController = {
-    shutdown(): void
-}
-
-export type HttpServer = (config: HttpServerConfig) => Promise<HttpServerController>

src/http/fastify.ts

@@ -1,82 +0,0 @@
-import Fastify, { FastifyBaseLogger, FastifyReply, FastifyRequest, HookHandlerDoneFunction } from 'fastify'
-import { HttpResponse, HttpServer } from './api'
-import { Logger } from 'homebridge'
-import { Bindings, ChildLoggerOptions } from 'fastify/types/logger'
-import { LogFn } from 'pino'
-
-/*class PinoLoggerBridge implements FastifyBaseLogger {
-
-    constructor(private readonly logger: Logger) {
-    }
-
-    child(bindings: Bindings, options: ChildLoggerOptions | undefined): FastifyBaseLogger {
-        return this
-    }
-
-    debug(m: string|unknown, ...args: unknown[]) {
-        this.logger.debug(typeof m === 'string' ? m : JSON.stringify(m), ...args)
-    }
-
-    error: LogFn;
-    fatal: pino.LogFn;
-    info: pino.LogFn;
-    level: pino.LevelWithSilent | string;
-    silent: pino.LogFn;
-    trace: pino.LogFn;
-    warn: pino.LogFn;
-}*/
-
-function adaptResponseToReply(response: HttpResponse, reply: FastifyReply): void {
-    if (response.statusCode) {
-        reply.code(response.statusCode)
-    }
-    if (response.body) {
-        reply.send(response.body)
-    }
-
-    if (response.headers) {
-        reply.headers(response.headers)
-    }
-}
-
-export const serve: HttpServer = async ({
-    port,
-    requestInterceptor,
-    metricsController,
-    notFoundController,
-    errorController,
-}) => {
-    const fastify = Fastify({
-        // logger
-    })
-
-    fastify.addHook('onRequest', (request: FastifyRequest, reply: FastifyReply, next: HookHandlerDoneFunction) => {
-        const response = requestInterceptor()
-
-        if (response) {
-            adaptResponseToReply(response, reply)
-        }
-
-        next()
-    })
-
-    fastify.setErrorHandler(async (error, request: FastifyRequest, reply: FastifyReply) => {
-        adaptResponseToReply(errorController(error), reply)
-    })
-
-    fastify.setNotFoundHandler(async (request: FastifyRequest, reply: FastifyReply) => {
-        adaptResponseToReply(notFoundController(), reply)
-    })
-
-    fastify.get('/metrics', async (request: FastifyRequest, reply: FastifyReply) => {
-        adaptResponseToReply(metricsController(), reply)
-    })
-
-    await fastify.listen({ port, host: '::' })
-
-    return {
-        shutdown() {
-            fastify.close()
-        },
-    }
-}

src/metrics.ts

@@ -1,4 +1,4 @@
-import type { Device, Accessory, NumberTypes, Service } from './boundaries'
+import type { Accessory, Device, Service } from './boundaries'
 import { isType } from './std'
 import { NUMBER_TYPES } from './boundaries'
 

src/platform.ts

@@ -1,15 +1,14 @@
-import { API, Logger, PlatformConfig, IndependentPlatformPlugin } from 'homebridge'
+import { API, IndependentPlatformPlugin, Logger, PlatformConfig } from 'homebridge'
 
-import { Metric, aggregate } from './metrics'
-import { discover } from './discovery/hap_node_js_client'
-import { serve } from './http/fastify'
-import { HttpServerController } from './http/api'
-import { MetricsRenderer } from './prometheus'
+import { aggregate } from './metrics'
+import { discover } from './adapters/discovery/hap_node_js_client'
+import { serve } from './adapters/http/fastify'
+import { HttpServerController } from './adapters/http/api'
+import { PrometheusServer } from './prometheus'
 
 export class PrometheusExporterPlatform implements IndependentPlatformPlugin {
-    private metrics: Metric[] = []
-    private metricsDiscovered = false
-    private http: HttpServerController | undefined = undefined
+    private readonly httpServer: PrometheusServer
+    private httpServerController: HttpServerController | undefined = undefined
 
     constructor(public readonly log: Logger, public readonly config: PlatformConfig, public readonly api: API) {
         this.log.debug('Initializing platform %s', this.config.platform)
@@ -18,12 +17,22 @@ export class PrometheusExporterPlatform implements IndependentPlatformPlugin {
 
         this.api.on('shutdown', () => {
             this.log.debug('Shutting down %s', this.config.platform)
-            if (this.http) {
-                this.http.shutdown()
+            if (this.httpServerController) {
+                this.httpServerController.shutdown()
             }
         })
 
-        this.startHttpServer()
+        this.log.debug('Starting probe HTTP server on port %d', this.config.probe_port)
+
+        this.httpServer = new PrometheusServer(this.config.probe_port, this.log, this.config.debug)
+        serve(this.httpServer)
+            .then((httpServerController) => {
+                this.log.debug('HTTP server started on port %d', this.config.probe_port)
+                this.httpServerController = httpServerController
+            })
+            .catch((e) => {
+                this.log.error('Failed to start probe HTTP server on port %d: %o', this.config.probe_port, e)
+            })
 
         this.api.on('didFinishLaunching', () => {
             this.log.debug('Finished launching %s', this.config.platform)
@@ -45,55 +54,6 @@ export class PrometheusExporterPlatform implements IndependentPlatformPlugin {
         this.log.debug('Configuration materialized: %o', this.config)
     }
 
-    private startHttpServer(): void {
-        this.log.debug('Starting probe HTTP server on port %d', this.config.probe_port)
-
-        const contentTypeHeader = { 'Content-Type': 'text/plain; charset=UTF-8' }
-        serve({
-            port: this.config.probe_port,
-            logger: this.log,
-            requestInterceptor: () => {
-                if (!this.metricsDiscovered) {
-                    return {
-                        statusCode: 503,
-                        headers: { ...contentTypeHeader, 'Retry-After': '10' },
-                        body: 'Discovery pending',
-                    }
-                }
-            },
-            metricsController: () => {
-                const renderer = new MetricsRenderer('homebridge')
-                const metrics = this.metrics.map((metric) => renderer.render(metric)).join('\n')
-
-                return {
-                    statusCode: 200,
-                    headers: contentTypeHeader,
-                    body: metrics,
-                }
-            },
-            notFoundController: () => ({
-                statusCode: 404,
-                headers: contentTypeHeader,
-                body: 'Not found. Try /metrics',
-            }),
-            errorController: (e) => {
-                this.log.error('HTTP request error: %o', e)
-                return {
-                    statusCode: 500,
-                    headers: contentTypeHeader,
-                    body: 'Server error',
-                }
-            },
-        })
-            .then((http) => {
-                this.log.debug('HTTP server started on port %d', this.config.probe_port)
-                this.http = http
-            })
-            .catch((e) => {
-                this.log.error('Failed to start probe HTTP server on port %d: %o', this.config.probe_port, e)
-            })
-    }
-
     private startHapDiscovery(): void {
         this.log.debug('Starting HAP discovery')
         discover({
@@ -105,9 +65,9 @@ export class PrometheusExporterPlatform implements IndependentPlatformPlugin {
             debug: this.config.debug,
         })
             .then((devices) => {
-                this.metrics = aggregate(devices, new Date())
-                this.metricsDiscovered = true
-                this.log.debug('HAP discovery completed, %d metrics discovered', this.metrics.length)
+                const metrics = aggregate(devices, new Date())
+                this.httpServer.updateMetrics(metrics)
+                this.log.debug('HAP discovery completed, %d metrics discovered', metrics.length)
                 this.startHapDiscovery()
             })
             .catch((e) => {

src/prometheus.ts

@@ -1,4 +1,7 @@
 import { Metric } from './metrics'
+import { Logger } from 'homebridge'
+import { HttpResponse } from './adapters/http/api'
+import { HttpServer } from './http'
 
 function escapeString(str: string) {
     return str.replace(/\\/g, '\\\\').replace(/\n/g, '\\n')
@@ -68,3 +71,55 @@ export class MetricsRenderer {
         return sanitizePrometheusMetricName(this.prefix.replace(/_+$/, '') + '_' + name)
     }
 }
+
+const contentTypeHeader = { 'Content-Type': 'text/plain; charset=UTF-8' }
+
+export class PrometheusServer implements HttpServer {
+    private metricsInitialized = false
+    private metrics: Metric[] = []
+
+    constructor(public readonly port: number, public readonly log: Logger, public readonly debug: boolean) {}
+
+    onRequest(): HttpResponse | undefined {
+        if (!this.metricsInitialized) {
+            return {
+                statusCode: 503,
+                headers: { ...contentTypeHeader, 'Retry-After': '10' },
+                body: 'Metrics discovery pending',
+            }
+        }
+    }
+
+    onMetrics(): HttpResponse {
+        const renderer = new MetricsRenderer('homebridge')
+        const metrics = this.metrics.map((metric) => renderer.render(metric)).join('\n')
+
+        return {
+            statusCode: 200,
+            headers: contentTypeHeader,
+            body: metrics,
+        }
+    }
+
+    onNotFound(): HttpResponse {
+        return {
+            statusCode: 404,
+            headers: contentTypeHeader,
+            body: 'Not found. Try /metrics',
+        }
+    }
+
+    onError(error: unknown): HttpResponse {
+        this.log.error('HTTP request error: %o', error)
+        return {
+            statusCode: 500,
+            headers: contentTypeHeader,
+            body: 'Server error',
+        }
+    }
+
+    updateMetrics(metrics: Metric[]): void {
+        this.metrics = metrics
+        this.metricsInitialized = true
+    }
+}

src/std.ts

@@ -1,5 +1,5 @@
 type Types = 'string' | 'number' | 'boolean' | 'object'
-type TypeMap = {
+interface TypeMap {
     string: string
     number: number
     boolean: boolean

tsconfig.json

@@ -14,5 +14,5 @@
         "resolveJsonModule": true
     },
     "include": ["src/"],
-    "exclude": ["**/*.test.ts", "node_modules/hap-nodejs/**/**"]
+    "exclude": []
 }