@flarelabs-net/workers-observability-utils/dist/logsTail.js

A collection of Utilities for Capturing Logs and Metrics from Cloudflare Workers

import { TraceItemDb } from "./traceItem";
export class LogsTail {
    #logSinks;
    #maxBufferSize;
    #maxBufferDuration;
    #flushId = 0;
    #traceItems = new TraceItemDb();
    #flushScheduled = false;
    constructor(options) {
        this.#logSinks = options.sinks;
        this.#maxBufferSize = options.maxBufferSize || 25;
        this.#maxBufferDuration = Math.min(options.maxBufferDuration || 5, 30);
    }
    processTraceItems(traceItems, ctx) {
        // Store all trace items in the buffer
        this.#traceItems.storeTraceItems(traceItems);
        // Check if we need to flush immediately due to buffer size
        if (this.#traceItems.getTraceItems().length >= this.#maxBufferSize) {
            if (this.#flushScheduled) {
                this.#flushScheduled = false;
            }
            this.#flushId++;
            // Flush immediately
            ctx.waitUntil(this.#performFlush());
            return;
        }
        if (this.#flushScheduled) {
            return;
        }
        // Only schedule flush if there are trace items to flush
        if (this.#traceItems.getTraceItems().length > 0) {
            this.#flushScheduled = true;
            const scheduleFlush = async () => {
                try {
                    const localFlushId = ++this.#flushId;
                    await scheduler.wait(this.#maxBufferDuration * 1000);
                    if (localFlushId === this.#flushId) {
                        await this.#performFlush();
                    }
                }
                catch (error) { }
            };
            ctx.waitUntil(scheduleFlush());
        }
    }
    async #performFlush() {
        const items = this.#traceItems.getTraceItems();
        // Reset batch and flush state
        this.#flushScheduled = false;
        this.#traceItems.clear();
        // Skip if no items to flush
        if (items.length === 0) {
            return;
        }
        try {
            const results = await Promise.allSettled(this.#logSinks.map((sink) => sink.sendLogs(items)));
            const successfulSinks = results.filter((el) => el.status === "fulfilled");
            if (successfulSinks.length > 0) {
                console.debug(`Flushed ${items.length} logs to ${successfulSinks.length} sink(s) successfully.`, {
                    logs: items.length,
                    sinks: successfulSinks.length,
                });
            }
            const errors = results.filter((el) => el.status === "rejected");
            if (errors.length > 0) {
                const sinkErrors = errors.map((error) => {
                    return `${error.reason instanceof Error ? error.reason.message : String(error.reason)}`;
                });
                console.error(`Failed to flush logs to ${errors.length} sink(s): ${sinkErrors.join(', ')}`, {
                    logs: items.length,
                    sinks: errors.length,
                    errors: sinkErrors,
                });
            }
        }
        catch (error) {
            console.error("Error flushing logs batch:", error);
        }
    }
}