v0.3.00: Basic Built-in Metric Sources

[laplaque]

Epic: Custom Metrics Collection and Registration

Epic Issue: #20
Depends on: #22 (v0.2.00: Foundation & Multiple OpenTelemetry Metric Types)

Overview

Implement fundamental metric source types for immediate value: HTTP endpoints, command execution, and log file parsing.

Deliverables

1. HTTP Endpoint Source (common/metric_sources/http_source.py)

• Poll REST/HTTP endpoints for metrics data
• Support JSON response parsing with JSONPath expressions
• Configurable intervals, timeouts, and retry logic
• Authentication support (Bearer tokens, basic auth)
• Response validation and error handling

2. Command Execution Source (common/metric_sources/command_source.py)

• Execute shell commands and parse output for metrics
• Support for various output formats (JSON, CSV, plain text)
• Regex-based value extraction from command output
• Command timeout and error handling
• Security considerations for command execution

3. Log File Parsing Source (common/metric_sources/log_source.py)

• Monitor log files for metric-relevant patterns
• Regex-based pattern matching and value extraction
• File rotation handling and position tracking
• Rate-based metrics (errors per minute, transactions per second)
• Configurable file paths and update intervals

4. Enhanced Configuration

• Extended TOML configuration for new source types
• Validation for source-specific parameters
• Configuration templates and examples

5. Comprehensive Testing

• Unit tests for each source type
• Integration tests with mock services
• Performance and reliability testing
• Documentation and usage examples

Configuration Example

[[custom_metrics.sources]]
name = "api_health"
type = "http"
url = "http://localhost:8080/health"
interval = 30
metrics = [
    {name = "response_time", otel_type = "histogram", json_path = "$.response_time"},
    {name = "active_connections", otel_type = "gauge", json_path = "$.connections.active"}
]

[[custom_metrics.sources]]
name = "error_monitor"
type = "log_file"
path = "/var/log/app.log"
interval = 10
metrics = [
    {name = "error_count", otel_type = "counter", pattern = "ERROR", unit = "1"}
]

Success Criteria

• 3 production-ready built-in source types
• Real-world integration examples
• Performance benchmarks established
• 85%+ test coverage
• Comprehensive documentation

Milestone

Target: v0.3.00