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uengage.io/php-logger

Structured observability logging for uEngage platform services. Write logs to a local file, POST them over HTTP, or emit to stdout - same JSON schema regardless of transport.

Table of Contents

• uengage.io/php-logger
  • Table of Contents
  • Overview
  • Requirements
  • Installation
  • Quick Start
  • File transporter (server / EC2)
  • HTTP transporter (no cloud agent)
  • Stdout transporter (Lambda / Docker)
  • Log Schema
  • Initialization
  • Config Reference
  • Transporters
  • File Transporter
  • HTTP Transporter
  • Stdout Transporter
  • Log Methods
  • Method Signature
  • Log Options Reference
  • Level Filtering
  • Graceful Shutdown
  • CodeIgniter 2 Integration
  • Prerequisite - load Composer autoloader
  • Logger_service library
  • Flushing HTTP batch mode in CI2
  • CodeIgniter 4 Integration
  • PHP-Specific Notes
  • Examples
  • Business event - order placed
  • Engineering error - payment gateway timeout
  • Warning - rate limit approaching
  • Debug - database query
  • Architecture
  • Running Tests

Overview

uengage/logger provides a single Logger class with four log-level methods (info, error, debug, warn). On initialization you choose a transport:

The log schema is identical to the Node.js @uengage/logger package - uniform cross-service log analysis.

Requirements

• PHP >= 7.1
• ext-curl (required for HTTP transporter; standard on virtually all hosting environments)
• Composer

Installation

Quick Start

File transporter (server / EC2)

HTTP transporter (no cloud agent)

Stdout transporter (Lambda / Docker)

Log Schema

• timestamp … message - always present
• user_id, error, context - omitted when not passed

Initialization

Validates synchronously; throws \InvalidArgumentException immediately if anything required is missing or invalid.

Config Reference

Transporters

File Transporter

Appends one NDJSON line per entry to {basePath}/application/{product}.log. The directory is created automatically; all services for the same product on a host share one file.

File rotation - when the file reaches maxFileSizeBytes:

Configure your cloud agent to watch application/edge.log* to pick up rotated files. Writes use FILE_APPEND | LOCK_EX - safe for concurrent PHP-FPM workers.

HTTP Transporter

POSTs log entries to an HTTP endpoint via cURL.

• Immediate mode (batchSize: 1) - one POST per call; body is a plain JSON object.
• Batch mode (default batchSize: 5) - entries queue; body is a JSON array. Call $logger->destroy() before exit to flush the remaining queue.
• cURL errors and non-2xx responses are written to error_log() with prefix [uengage-logger][http]; the host application is never interrupted.

Stdout Transporter

Writes one NDJSON line per entry to php://stdout. No config knobs.

Best for AWS Lambda (Bref / custom PHP runtime) and Docker - the runtime captures stdout into CloudWatch Logs or your log-aggregation service. Uses php://stdout rather than the STDOUT constant, which is undefined under PHP-FPM and most Lambda runtime adapters.

Log Methods

Method Signature

Log Options Reference

Level Filtering

Set minLevel to suppress low-priority logs without changing call sites (default: 'warn'):

Graceful Shutdown

Register shutdown for HTTP batch mode:

CodeIgniter 2 Integration

Prerequisite - load Composer autoloader

CI2 does not load Composer's autoloader by default. Add one of the following:

Option A - application/config/config.php (recommended):

Option B - index.php (before the CI bootstrap):

Logger_service library

Logger_service acts as a lazy factory for the logger. Load it once per controller; it caches one Logger instance per service name for the lifetime of the request.

1. Load the library in your controller

2. Get a logger and write a log

3. Use from a library / helper (no $this)

How it works internally

Tip - dynamic log level

Flushing HTTP batch mode in CI2

Register destroy() via a post_system hook:

Or via register_shutdown_function in your base controller:

CodeIgniter 4 Integration

CI4 includes Composer autoloading out of the box - no manual require needed.

Register as a CI4 Service (app/Config/Services.php):

Use in any Controller, Model, or Library:

Flushing HTTP batch mode - register destroy() in a CI4 After-filter or your BaseController destructor:

PHP-Specific Notes

Examples

Business event - order placed

Engineering error - payment gateway timeout

Warning - rate limit approaching

Debug - database query

Architecture

Error contract: every transporter catches all internal errors and writes to error_log(). A logging failure never throws to the caller.

Running Tests

Expected output: