moniof — Monitor Over Fetch

moniof (Monitor Over Fetch) is an Actix Web middleware + instrumentation crate to:

• detect N+1 / over-fetch patterns
• track per-request DB latency
• expose Prometheus metrics
• send Slack alerts
• work with MongoDB and SQLx (Postgres / MySQL / SQLite)

Inspired by Ruby's bullet gem — but built for Rust + Actix.

✨ Features

• 🧱 Actix middleware (MoniOF)
• 🕵️ N+1 & Over-Fetch detection
• 📡 MongoDB instrumentation (command events)
• 🧮 SQLx instrumentation (via tracing spans)
• 📊 Prometheus metrics
• 🔔 Slack alerts for slow DB calls
• 🧾 Auto response headers:
  • x-moniof-total
  • x-moniof-db-total-ms
  • x-moniof-elapsed-ms
  • x-moniof-slowest-key
  • x-moniof-n-plus-one-key

🚀 Installation

Add to your app's Cargo.toml:

[dependencies]
moniof = { version = "0.1.0", features = ["mongodb", "sqlx"] }
actix-web = "4"
tracing = "0.1"
tracing-subscriber = { version = "0.3", features = ["env-filter", "fmt", "registry"] }

mongodb = "2"
sqlx = { version = "0.8", features = ["postgres", "runtime-tokio-rustls"] }

🧩 Public API

pub use config::{MoniOFGlobalConfig, initiate, global};
pub use config::MoniOFConfig;
pub use services::http::MoniOF;
pub use observability::prom;

#[cfg(feature = "mongodb")]
pub use instrumentation::mongo_events::MOFMongoEvents;

#[cfg(feature = "sqlx")]
pub use instrumentation::sql_events::MOFSqlEvents;

🌐 Step 1 — Initialize moniof globally

Call once in main():

use moniof::{MoniOFGlobalConfig, initiate as moniof_initiate};

fn main() {
    moniof_initiate(MoniOFGlobalConfig {
        slack_webhook: None,
        slow_db_threshold_ms: Some(0),
        low_db_threshold_ms: Some(0),
        log_each_db_event: true,
        ..Default::default()
    });

    // Start Actix...
}

This installs:

• tracing subscriber
• SQLx instrumentation (if feature enabled)
• log filter for moniof

🌍 Step 2 — Add Actix Middleware

use moniof::MoniOF;

HttpServer::new(|| {
    App::new()
        .wrap(MoniOF::new())
})

Now each request produces:

• DB stats
• detection of N+1
• enriched response headers

🍃 MongoDB Integration

Attach moniof's MongoDB handler:

use moniof::MOFMongoEvents;
use std::sync::Arc;
use mongodb::{Client, options::ClientOptions};

let mut opts = ClientOptions::parse(&mongo_uri).await?;
opts.command_event_handler = Some(Arc::new(MOFMongoEvents::default()));

let client = Client::with_options(opts)?;
let db = client.database("mydb");

Every find, insert, update is tracked.

🧮 SQLx Integration

If your crate enables:

features = ["sqlx"]

Then SQLx logs are automatically hooked.

Use SQLx normally:

let rows = sqlx::query!("SELECT id FROM users")
    .fetch_all(pool)
    .await?;

moniof will record:

• query count
• query latency
• over-fetch patterns

and log:

moniof::sql: SQL completed key="select from users" latency_ms=2

📈 Prometheus Metrics

Expose /metrics:

use moniof::prom;

HttpServer::new(|| {
    App::new()
        .service(prom::metrics())
})

Example metrics:

moniof_http_requests_total
moniof_http_request_duration_seconds
moniof_db_total_latency_seconds
moniof_mongo_command_duration_seconds

🔔 Slack Alerts

Enabled when slack_webhook is set:

slack_webhook: Some("https://hooks.slack.com/...".to_string())

Alert types:

• Slow DB commands
• Mongo/SQLx failures
• N+1 detection

🧪 Example Response Headers

x-moniof-total: 5
x-moniof-db-total-ms: 12
x-moniof-elapsed-ms: 18
x-moniof-slowest-key: users/find
x-moniof-n-plus-one-key: users/find

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• Built with Actix Web - Fast, powerful web framework

Made with ❤️ by the [Srotas Space] (https://srotas.space/open-source)

Support

• Documentation: docs.rs/moniof
• Issues: GitHub Issues
• Discussions: GitHub Discussions