Introduction to Tracer

The tracer API offers developers a powerful tool for tracing and diagnosing their applications. It provides comprehensive insights into the behavior of applications, enabling developers to troubleshoot and optimize their code effectively. Below, we explore some of the impressive functionalities provided by the tracer API along with coding examples.

API Examples

1. Initializing Tracer

To start using the tracer, you first need to initialize it.

 const tracer = require('tracer').console({
    format: "{{message}}",
    dateformat: "HH:MM:ss.L"
}); tracer.info("Tracer is initialized!"); 

2. Basic Logging

You can log information, warnings, and errors easily with tracer.

 tracer.log('This is a log message'); tracer.trace('This is a trace message'); tracer.debug('This is a debug message'); tracer.info('This is an info message'); tracer.warn('This is a warning message'); tracer.error('This is an error message'); 

3. Customizing Output

Customize the log output with different colors and formats.

 const logger = require('tracer').console({
    format: "{{timestamp}} <{{title}}> {{message}} (in {{file}}:{{line}})",
    dateformat: "yyyy-mm-dd HH:MM:ss.L"
});
logger.log('This is a custom log message'); 

4. JSON Output

Switching to JSON output for better structured logging.

 const jsonLogger = require('tracer').dailyfile({
    root:'.',
    maxLogFiles: 10,
    format: "{{message}} ({{file}}:{{line}})",
    dateformat: "HH:MM:ss.L"
});
jsonLogger.log('Log message in JSON format'); 

5. Timestamp Customization

Adding precise timestamps to your logs.

 const timestampLogger = require('tracer').console({
    format: "[{{timestamp}}] <{{title}}> {{message}}",
    dateformat: "UTC:yyyy-mm-dd'T'HH:MM:ss.l'Z'"
});
timestampLogger.log('Logging with timestamps'); 

6. Conditional Logging

Enabling or disabling logs based on certain conditions.

 const conditionLogger = require('tracer').colorConsole({
    filter : function (level, message) {
        return level === 'error' || message.includes('critical');
    }
});
conditionLogger.log('This is a normal log message'); conditionLogger.error('This is an error message'); 

7. Writing Logs to Files

Persisting logs to files for later analysis.

 const fileLogger = require('tracer').dailyfile({
    root:'./logs',
    maxLogFiles: 3,
    allLogsFileName: 'myApp'
});
fileLogger.log('Log message saved to file'); 

Application Example

Below is a small Express.js application demonstrating the usage of some tracer APIs.

 const express = require('express'); const tracer = require('tracer'); const app = express(); const port = 3000;
const logger = tracer.console({
    format: "{{timestamp}} <{{title}}> {{message}}",
    dateformat: "HH:MM:ss.L"
});
app.use((req, res, next) => {
    logger.info(\`Received request: \${req.method} \${req.url}\`);
    next();
});
app.get('/', (req, res) => {
    logger.log('Handling root route');
    res.send('Hello World!');
});
app.listen(port, () => {
    logger.info(\`App listening at http://localhost:\${port}\`);
}); 

By using the tracer API in your applications, you can greatly improve log management and debugging capabilities. Happy coding!

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