Bull provides methods to track progress and log information during job execution.
progress()
progress(progress?: number | object): Promise
Job progress as a number (0-100) or any serializable object representing progress
Setting Progress
You can report progress as a percentage (number) or as a custom object:
queue.process(async (job) => {
// Report progress as percentage
await job.progress(10);
// Do some work...
await job.progress(50);
// Do more work...
await job.progress(100);
return { success: true };
});
Custom Progress Objects
For more detailed progress tracking, use an object:
queue.process(async (job) => {
const total = job.data.items.length;
for (let i = 0; i < total; i++) {
// Process item
processItem(job.data.items[i]);
// Report detailed progress
await job.progress({
processed: i + 1,
total: total,
percentage: Math.round(((i + 1) / total) * 100),
currentItem: job.data.items[i].name
});
}
return { success: true };
});
Reading Progress
Call progress() without arguments to read the current progress:
const currentProgress = await job.progress();
console.log('Current progress:', currentProgress);
Listening to Progress Events
queue.on('progress', (job, progress) => {
console.log(`Job ${job.id} is ${progress}% complete`);
});
// Global progress events (across all workers)
queue.on('global:progress', (jobId, progress) => {
console.log(`Job ${jobId} is ${progress}% complete`);
});
log()
log(row: string): Promise
Queue#getJobLogs().
Adding Logs
queue.process(async (job) => {
await job.log('Starting job processing');
try {
await job.log('Fetching data from API...');
const data = await fetchData(job.data.url);
await job.log(`Received ${data.length} items`);
await job.log('Processing items...');
const result = await processData(data);
await job.log('Job completed successfully');
return result;
} catch (error) {
await job.log(`Error: ${error.message}`);
throw error;
}
});
Error Logging
queue.process(async (job) => {
for (let i = 0; i < job.data.items.length; i++) {
try {
await processItem(job.data.items[i]);
await job.log(`✓ Processed item ${i + 1}`);
} catch (error) {
await job.log(`✗ Failed to process item ${i + 1}: ${error.message}`);
}
}
});
Queue#getJobLogs()
getJobLogs(jobId: string, start?: number, end?: number): Promise<{
logs: string[],
count: number
}>
Start index for pagination (default: 0)
End index for pagination (default: -1, meaning all logs)
Total number of logs (useful for pagination)
Retrieving Logs
// Get all logs for a job
const { logs, count } = await queue.getJobLogs('job-123');
console.log(`Job has ${count} log entries:`);
logs.forEach(log => console.log(log));
Paginated Logs
// Get first 10 logs
const page1 = await queue.getJobLogs('job-123', 0, 9);
console.log(`Showing 10 of ${page1.count} logs:`);
page1.logs.forEach(log => console.log(log));
// Get next 10 logs
const page2 = await queue.getJobLogs('job-123', 10, 19);
Full Example
const queue = new Queue('processing');
queue.process(async (job) => {
await job.log('Job started');
await job.progress(0);
const steps = 5;
for (let i = 1; i <= steps; i++) {
await job.log(`Step ${i}/${steps}`);
await performStep(i);
await job.progress((i / steps) * 100);
}
await job.log('Job completed');
return { success: true };
});
// Later, retrieve logs
const job = await queue.add({ data: 'test' });
await job.finished();
const { logs } = await queue.getJobLogs(job.id);
console.log('Job logs:');
logs.forEach(log => console.log(` ${log}`));