refactor: reuse puppeteer browser and log print job phases

src/services/printer.processor.ts

@@ -1,26 +1,113 @@
 import { Processor, WorkerHost } from '@nestjs/bullmq';
+import { Logger, OnApplicationShutdown } from '@nestjs/common';
 import { Job } from 'bullmq';
+import { performance } from 'node:perf_hooks';
 import * as puppeteer from 'puppeteer';
 import * as pdfPrinter from 'pdf-to-printer';
 import * as path from 'path';
 import * as fs from 'fs';
 import * as os from 'os';
+import { PrintHtmlDto } from '../dto/print-html.dto';
 
 @Processor('printer')
-export class PrinterProcessor extends WorkerHost {
-  
-  async process(job: Job<any>): Promise<any> {
+export class PrinterProcessor
+  extends WorkerHost
+  implements OnApplicationShutdown
+{
+  private readonly logger = new Logger(PrinterProcessor.name);
+  private browser: puppeteer.Browser | undefined;
+  private browserLaunching: Promise<puppeteer.Browser> | undefined;
+
+  private async getBrowser(): Promise<puppeteer.Browser> {
+    if (this.browser?.isConnected()) return this.browser;
+    if (this.browserLaunching) return this.browserLaunching;
+
+    this.browserLaunching = puppeteer
+      .launch({
+        headless: true,
+        args: ['--no-sandbox', '--disable-setuid-sandbox'],
+      })
+      .then((browser) => {
+        this.browser = browser;
+        return browser;
+      })
+      .finally(() => {
+        this.browserLaunching = undefined;
+      });
+
+    return this.browserLaunching;
+  }
+
+  async onApplicationShutdown(): Promise<void> {
+    try {
+      await this.browser?.close();
+    } catch (err) {
+      this.logger.warn(`Failed to close Puppeteer browser: ${String(err)}`);
+    } finally {
+      this.browser = undefined;
+    }
+  }
+
+  private logJob(
+    level: 'log' | 'warn' | 'error' | 'debug',
+    payload: Record<string, unknown>,
+    error?: unknown,
+  ): void {
+    const message = JSON.stringify(payload);
+    if (level === 'error') {
+      const stack = error instanceof Error ? error.stack : undefined;
+      this.logger.error(message, stack);
+      return;
+    }
+
+    if (level === 'warn') {
+      this.logger.warn(message);
+      return;
+    }
+
+    if (level === 'debug') {
+      this.logger.debug(message);
+      return;
+    }
+
+    this.logger.log(message);
+  }
+
+  async process(job: Job<PrintHtmlDto>): Promise<any> {
     const data = job.data;
-    const tempFilePath = path.join(os.tmpdir(), `print-${job.id}-${Date.now()}.pdf`);
-    let browser;
+    const printerName = data?.printerName;
+    const jobCtx = {
+      jobId: job.id,
+      jobName: job.name,
+      printerName,
+    };
+
+    const tempFilePath = path.join(
+      os.tmpdir(),
+      `print-${job.id}-${Date.now()}.pdf`,
+    );
+    let page: puppeteer.Page | undefined;
+    let phase: 'render' | 'pdf' | 'spool' | 'unknown' = 'unknown';
+
+    const durationsMs: {
+      render?: number;
+      pdf?: number;
+      spool?: number;
+      total?: number;
+    } = {};
+
+    const totalStart = performance.now();
+
+    this.logJob('log', {
+      event: 'print_job_start',
+      ...jobCtx,
+      width: data?.width,
+      height: data?.height,
+    });
 
     try {
-      browser = await puppeteer.launch({ 
-        headless: true,
-        args: ['--no-sandbox', '--disable-setuid-sandbox'] 
-      });
-      
-      const page = await browser.newPage();
+      const browser = await this.getBrowser();
+      page = await browser.newPage();
       const width = data.width || '80mm';
       const height = data.height;
 
@@ -40,30 +127,97 @@ export class PrinterProcessor extends WorkerHost {
         </html>
       `;
 
+      phase = 'render';
+      const renderStart = performance.now();
       await page.setContent(fullHtml, { waitUntil: 'networkidle0' });
-      
-      const pdfOptions: any = { 
-        path: tempFilePath, 
+      durationsMs.render = performance.now() - renderStart;
+      this.logJob('log', {
+        event: 'print_job_phase',
+        phase,
+        durationMs: durationsMs.render,
+        ...jobCtx,
+      });
+
+      const pdfOptions: any = {
+        path: tempFilePath,
         printBackground: true,
         width: width,
-        margin: { top: '0px', right: '0px', bottom: '0px', left: '0px' }
+        margin: { top: '0px', right: '0px', bottom: '0px', left: '0px' },
       };
 
       if (height) pdfOptions.height = height;
 
+      phase = 'pdf';
+      const pdfStart = performance.now();
       await page.pdf(pdfOptions);
-      await browser.close();
+      durationsMs.pdf = performance.now() - pdfStart;
+      this.logJob('log', {
+        event: 'print_job_phase',
+        phase,
+        durationMs: durationsMs.pdf,
+        ...jobCtx,
+      });
 
-      await pdfPrinter.print(tempFilePath, { 
+      await page.close();
+      page = undefined;
+
+      phase = 'spool';
+      const spoolStart = performance.now();
+      await pdfPrinter.print(tempFilePath, {
         printer: data.printerName,
-        silent: true 
+        silent: true,
+      });
+      durationsMs.spool = performance.now() - spoolStart;
+      this.logJob('log', {
+        event: 'print_job_phase',
+        phase,
+        durationMs: durationsMs.spool,
+        ...jobCtx,
+      });
+
+      durationsMs.total = performance.now() - totalStart;
+      this.logJob('log', {
+        event: 'print_job_success',
+        ...jobCtx,
+        durationsMs,
       });
 
       return { status: 'success', jobId: job.id };
-
     } catch (error) {
-      if (browser) await browser.close();
-      console.error(`Erro no Job ${job.id}:`, error);
+      if (page) {
+        try {
+          await page.close();
+        } catch {
+          // ignore
+        }
+      }
+
+      const message = error instanceof Error ? error.message : String(error);
+      durationsMs.total = performance.now() - totalStart;
+      this.logJob(
+        'error',
+        {
+          event: 'print_job_error',
+          ...jobCtx,
+          phase,
+          durationsMs,
+          errorMessage: message,
+          errorType: error instanceof Error ? error.name : typeof error,
+        },
+        error,
+      );
+
+      // If the shared browser crashed/closed, reset it so next job can relaunch.
+      if (/Target closed|Browser closed|Protocol error/i.test(message)) {
+        try {
+          await this.browser?.close();
+        } catch {
+          // ignore
+        } finally {
+          this.browser = undefined;
+        }
+      }
+
       throw error;
     } finally {
       if (fs.existsSync(tempFilePath)) {
@@ -71,4 +225,4 @@ export class PrinterProcessor extends WorkerHost {
       }
     }
   }
-}
+}