graflog

Structured JSON logging optimized for Grafana ingestion. And abstraction boring tracing subscriber syntax, by the way.

Features

JSON-only structured logging
Grafana-optimized field naming
Thread-safe file appending
Zero-configuration setup
Consistent timestamp formatting
Service and component tagging
Distributed tracing with spans

Installation

cargo add graflog

Usage

use graflog::{init_logging, app_log, app_span};

fn main() {
    // Initialize logging - crashes if file path invalid
    init_logging!("/var/log/myapp.log", "payment-service", "api", "info");

    // Disable console output
    // init_logging!("/var/log/myapp.log", "payment-service", "api", "info", false);i
 
    // Log with automatic service/component tags
    app_log!(info, "Server started on port 8080");
    app_log!(error, "Database connection failed", error_code = 500);
 
    // Log with custom service/component
    app_log!(debug, "user-service", "auth", "Login attempt", user_id = 12345);
 
    // Create spans for distributed tracing
    let process_span = app_span!(
        "process_payment",
        user_id = %user_id,
        amount = amount
    );
    let _enter = process_span.enter();
    
    // Custom service/component span
    let auth_span = app_span!(
        "validate_token",
        "auth-service",
        "jwt",
        token_id = %token_id
    );
}

Grafana Integration

Logs are formatted with consistent fields:

service: Service identifier
component: Component within service
timestamp: RFC3339 formatted timestamp
level: Log level (trace, debug, info, warn, error)
Custom fields from your log statements

Perfect for Grafana Loki queries:

{service="payment-service"} | json | level="error"
{service="auth-service"} | json | component="jwt"

Command Line Usage

Pass log file path at startup:


cargo run -- --log-file /var/log/myapp.log --log-level info

No environment files needed - all parameters passed directly.

Supported log levels: trace, debug, info, warn, error