cc-utils/src/logExample/main.ts

/**
 * Example usage of the ccStructLog library.
 *
 * This file demonstrates various ways to use the restructured logging system,
 * including basic usage, custom configurations, and advanced scenarios.
 */

import {
    Logger,
    processor,
    ConsoleStream,
    FileStream,
    BufferStream,
    ConditionalStream,
    HOUR,
    jsonRenderer,
    LogLevel,
    textRenderer,
} from "../lib/ccStructLog";

// =============================================================================
// Custom Logger Configurations
// =============================================================================

print("\n=== Custom Logger Configurations ===");

// 4. Custom logger with specific processors and renderer
const customLogger = new Logger({
    processors: [
        processor.addTimestamp(),
        processor.addComputerId(),
        processor.addSource("CustomApp"),
        processor.addStaticFields({
            environment: "development",
            version: "2.1.0",
        }),
    ],
    renderer: jsonRenderer,
    streams: [
        new ConsoleStream(),
        new FileStream({
            filePath: "custom.log",
            rotationInterval: HOUR,
        }),
    ],
});

customLogger.info("Custom logger example", {
    feature: "user_management",
    operation: "create_user",
});

// =============================================================================
// Advanced Processor Examples
// =============================================================================

print("\n=== Advanced Processor Examples ===");

// 6. Custom processors
const addRequestId = (event: Map<string, unknown>) => {
    event.set("requestId", `req_${Math.random().toString(36).substr(2, 9)}`);
    return event;
};

const sanitizePasswords = (event: Map<string, unknown>) => {
    // Remove sensitive information
    if (event.has("password")) {
        event.set("password", "[REDACTED]");
    }
    if (event.has("token")) {
        event.set("token", "[REDACTED]");
    }
    return event;
};

const secureLogger = new Logger({
    processors: [
        processor.addTimestamp(),
        addRequestId,
        sanitizePasswords,
        processor.transformField("message", (msg) => `[SECURE] ${msg}`),
    ],
    renderer: jsonRenderer,
    streams: [new ConsoleStream()],
});

secureLogger.info("User login attempt", {
    username: "john_doe",
    password: "secret123",
    token: "abc123def456",
});

// =============================================================================
// Stream Examples
// =============================================================================

print("\n=== Stream Examples ===");

// 11. Buffer stream for batch processing
const bufferStream = new BufferStream(100); // Keep last 100 messages
const bufferLogger = new Logger({
    processors: [processor.addTimestamp()],
    renderer: textRenderer,
    streams: [
        new ConditionalStream(new ConsoleStream(), (msg, event) => {
            if (event.get("level") === LogLevel.Info) {
                return false;
            } else {
                return true;
            }
        }),
        bufferStream,
    ],
});

// Log several messages
for (let i = 0; i < 5; i++) {
    bufferLogger.info(`Buffered info message ${i}`, { iteration: i });
    bufferLogger.warn(`Buffered warn message ${i}`, { iteration: i });
}

// Get all buffered messages
const bufferedMessages = bufferStream.getMessages();
print(`Buffered ${bufferedMessages.length} messages:`);
for (const msg of bufferedMessages) {
    print(`  ${msg}`);
}

// 12. Multi-stream with different formats
const multiFormatLogger = new Logger({
    processors: [processor.addTimestamp(), processor.addComputerId()],
    renderer: (event) => "default", // This won't be used
    streams: [
        // Console with human-readable format
        {
            write: (_, event) => {
                const formatted = textRenderer(event);
                new ConsoleStream().write(formatted, event);
            },
        },
        // File with JSON format
        {
            write: (_, event) => {
                const formatted = jsonRenderer(event);
                new FileStream({ filePath: "structured.log" }).write(
                    formatted,
                    event,
                );
            },
        },
    ],
});

multiFormatLogger.info("Multi-format message", {
    feature: "logging",
    test: true,
});

// =============================================================================
// Error Handling and Edge Cases
// =============================================================================

print("\n=== Error Handling Examples ===");

// 13. Robust error handling
const robustLogger = new Logger({
    processors: [
        processor.addTimestamp(),
        // Processor that might fail
        (event) => {
            try {
                // Simulate potential failure
                if (Math.random() > 0.8) {
                    throw new Error("Processor failed");
                }
                event.set("processed", true);
                return event;
            } catch (error) {
                // Log processor errors but don't break the chain
                printError(`Processor error: ${String(error)}`);
                event.set("processor_error", true);
                return event;
            }
        },
    ],
    renderer: textRenderer,
    streams: [new ConsoleStream()],
});

// Log multiple messages to see error handling in action
for (let i = 0; i < 10; i++) {
    robustLogger.info(`Message ${i}`, { attempt: i });
}

// =============================================================================
// Cleanup Examples
// =============================================================================

print("\n=== Cleanup Examples ===");

// 14. Proper cleanup
const fileLogger = new Logger({
    processors: [processor.addTimestamp()],
    renderer: jsonRenderer,
    streams: [new FileStream({ filePath: "structured.log" })],
});

fileLogger.info("Temporary log entry");

// Clean shutdown - close all streams
fileLogger.close();

print("\n=== Examples Complete ===");
print("Check the generated log files:");
print("- app.log (daily rotation)");
print("- custom.log (hourly rotation)");
print("- all.log (complete log)");
print("- debug.log (detailed debug info)");
print("- structured.log (JSON format)");
print("- temp.log (temporary file, now closed)");