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@grest-ts/logger-console

Colored console logger implementation for @grest-ts/logger. Formats log entries with ANSI colors, timestamps, log levels, and context — designed to be readable when a human needs to read logs from the service console – useful for debugging when developing.

Quick Start

import {GG_LOG} from "@grest-ts/logger"
import {GGLoggerConsole} from "@grest-ts/logger-console"

// In your runtime's compose():
GG_LOG.get().addLogger(
    new GGLoggerConsole({showData: true})
)

Output looks like:

14:32:45 12345 INFO  MyService  Starting up
14:32:45 12345 ERROR MyService  Connection failed [stack trace...]

Options

new GGLoggerConsole({
    minLevel?: LogLevel,              // Filter by minimum level (default: LOG_LEVEL env var, or DEBUG)
    showData?: boolean,               // Include data objects in output (default: true)
    timestampFormat?: 'full' | 'time' // 'time' = HH:MM:SS (default), 'full' = YYYY-MM-DD HH:MM:SS
})

The LOG_LEVEL environment variable is respected automatically (DEBUG, INFO, WARN, ERROR, CRITICAL).

Enriching Logs with addContext()

The most useful feature — addContext() lets you inject extra information into every log line. The callback receives the parts array (the segments that make up each log line) and can push additional values into it. These appear between the source name and the message.

Real-World Example

private getLogger() {
    return new GGLoggerConsole({showData: true})
        .addContext((p) => {
            // Service name
            p.push(GGLocator.getScope().serviceName);

            // Trace ID (short) — for correlating logs across services
            if (GG_TRACE.has()) {
                p.push(GG_TRACE.get().spanId.slice(0, 6));
            }

            // Current HTTP request
            if (GG_HTTP_REQUEST.has()) {
                const req = GG_HTTP_REQUEST.get();
                p.push(req.method + " " + req.path);
            }

            // Authenticated user
            if (UserContext.has()) {
                const user = UserContext.get();
                p.push(user.username + "(" + user.id + ")");
            }

            // Tenant/company (multi-tenant apps)
            if (CompanyContext.has()) {
                p.push("C:" + CompanyContext.get().companyId);
            }
        })
}

This produces log lines like:

14:32:45 12345 INFO  OrderService realestate a3f2b1 POST /api/orders john(42) C:7  Creating order

Every part is context-aware — trace IDs, request info, and user context are only present when available (e.g. outside of an HTTP request, those parts are simply omitted). This makes logs self-describing: you can tell exactly which user, request, and service produced each line.

Log Output Format

Each log line is composed of these segments:

[timestamp] [pid] [level] [contextName] [custom context...] [message] [data] [error]

• timestamp — gray
• pid — process ID
• level — color-coded (green=INFO, yellow=WARN, red=ERROR, gray=DEBUG)
• contextName — cyan, the this or TAG string passed to GGLog.info(this, ...)
• custom context — added by addContext() providers
• message — colored by level
• data — structured data, auto-sanitized (large buffers, files, deep objects are summarized)
• error — stack traces, validation errors, and debug context are formatted with indentation