rustfs/crates/obs

rustfs-obs

Observability library for RustFS providing structured JSON logging, distributed tracing, and metrics via OpenTelemetry.

---

Features

Feature	Description
Structured logging	JSON-formatted logs via tracing-subscriber
Rolling-file logging	Daily / hourly rotation with automatic cleanup
Distributed tracing	OTLP/HTTP export to Jaeger, Tempo, or any OTel collector
Metrics	OTLP/HTTP export, bridged from the metrics crate facade
Log cleanup	Background task: size limits, gzip compression, retention policies
GPU metrics (optional)	Enable with the gpu feature flag

---

Quick Start

# Cargo.toml
[dependencies]
rustfs-obs = { version = "0.0.5" }

# GPU metrics support
rustfs-obs = { version = "0.0.5", features = ["gpu"] }

use rustfs_obs::init_obs;

#[tokio::main]
async fn main() {
    // Build config from environment variables, then initialise all backends.
    let _guard = init_obs(None).await.expect("failed to initialise observability");

    tracing::info!("RustFS started");

    // _guard is dropped here — all providers are flushed and shut down.
}

Keep _guard alive for the lifetime of your application. Dropping it triggers an ordered shutdown of every OpenTelemetry provider.

---

Initialisation

With an explicit OTLP endpoint

use rustfs_obs::init_obs;

let _guard = init_obs(Some("http://otel-collector:4318".to_string()))
    .await
    .expect("observability init failed");

With a custom config struct

use rustfs_obs::{AppConfig, OtelConfig, init_obs_with_config};

let config = AppConfig::new_with_endpoint(Some("http://localhost:4318".to_string()));
let _guard = init_obs_with_config(&config.observability)
    .await
    .expect("observability init failed");

---

Routing Logic

The library selects a backend automatically based on configuration:

1. Any OTLP endpoint set?
   └─ YES → Full OTLP/HTTP pipeline (traces + metrics + logs)

2. RUSTFS_OBS_LOG_DIRECTORY set to a non-empty path?
   └─ YES → Rolling-file JSON logging
            + Stdout mirror enabled if:
              - RUSTFS_OBS_LOG_STDOUT_ENABLED=true (explicit), OR
              - RUSTFS_OBS_ENVIRONMENT != "production" (automatic)

3. Default → Stdout-only JSON logging (all signals)

Key Points:

• When no log directory is configured, logs automatically go to stdout only (perfect for development)
• When a log directory is set, logs go to rolling files in that directory
• In non-production environments, stdout is automatically mirrored alongside file logging for visibility
• In production mode, you must explicitly set RUSTFS_OBS_LOG_STDOUT_ENABLED=true to see stdout in addition to files

---

Environment Variables

All configuration is read from environment variables at startup.

OTLP / Export

Variable	Default	Description
RUSTFS_OBS_ENDPOINT	(empty)	Root OTLP/HTTP endpoint, e.g. http://otel-collector:4318
RUSTFS_OBS_TRACE_ENDPOINT	(empty)	Dedicated trace endpoint (overrides root + /v1/traces)
RUSTFS_OBS_METRIC_ENDPOINT	(empty)	Dedicated metrics endpoint
RUSTFS_OBS_LOG_ENDPOINT	(empty)	Dedicated log endpoint
RUSTFS_OBS_TRACES_EXPORT_ENABLED	true	Toggle trace export
RUSTFS_OBS_METRICS_EXPORT_ENABLED	true	Toggle metrics export
RUSTFS_OBS_LOGS_EXPORT_ENABLED	true	Toggle OTLP log export
RUSTFS_OBS_USE_STDOUT	false	Mirror all signals to stdout alongside OTLP
RUSTFS_OBS_SAMPLE_RATIO	0.1	Trace sampling ratio 0.0–1.0
RUSTFS_OBS_METER_INTERVAL	15	Metrics export interval (seconds)

Service identity

Variable	Default	Description
RUSTFS_OBS_SERVICE_NAME	rustfs	OTel service.name
RUSTFS_OBS_SERVICE_VERSION	(crate version)	OTel service.version
RUSTFS_OBS_ENVIRONMENT	development	Deployment environment (production, development, …)

Local logging

Variable	Default	Description
RUSTFS_OBS_LOGGER_LEVEL	info	Log level; RUST_LOG syntax supported
RUSTFS_OBS_LOG_STDOUT_ENABLED	false	When file logging is active, also mirror to stdout
RUSTFS_OBS_LOG_DIRECTORY	(empty)	Directory for rolling log files. When empty, logs go to stdout only
RUSTFS_OBS_LOG_FILENAME	rustfs	Base filename for rolling logs (date suffix added automatically)
RUSTFS_OBS_LOG_ROTATION_TIME	hourly	Rotation granularity: minutely, hourly, or daily
RUSTFS_OBS_LOG_KEEP_FILES	30	Number of rolling files to keep

Log cleanup

Variable	Default	Description
RUSTFS_OBS_LOG_KEEP_COUNT	10	Minimum files the cleaner must always preserve
RUSTFS_OBS_LOG_MAX_TOTAL_SIZE_BYTES	2147483648	Hard cap on total log directory size (2 GiB)
RUSTFS_OBS_LOG_MAX_SINGLE_FILE_SIZE_BYTES	0	Per-file size cap; 0 = unlimited
RUSTFS_OBS_LOG_COMPRESS_OLD_FILES	true	Gzip-compress files before deleting
RUSTFS_OBS_LOG_GZIP_COMPRESSION_LEVEL	6	Gzip level 1 (fastest) – 9 (best)
RUSTFS_OBS_LOG_COMPRESSED_FILE_RETENTION_DAYS	30	Delete .gz archives older than N days; 0 = keep forever
RUSTFS_OBS_LOG_EXCLUDE_PATTERNS	(empty)	Comma-separated glob patterns to never clean up
RUSTFS_OBS_LOG_DELETE_EMPTY_FILES	true	Remove zero-byte files
RUSTFS_OBS_LOG_MIN_FILE_AGE_SECONDS	3600	Minimum file age (seconds) before cleanup
RUSTFS_OBS_LOG_CLEANUP_INTERVAL_SECONDS	21600	How often the cleanup task runs (6 hours)
RUSTFS_OBS_LOG_DRY_RUN	false	Report deletions without actually removing files

---

Examples

Stdout-only (development default)

# No RUSTFS_OBS_LOG_DIRECTORY set → stdout JSON
RUSTFS_OBS_LOGGER_LEVEL=debug ./rustfs

Rolling-file logging

export RUSTFS_OBS_LOG_DIRECTORY=/var/log/rustfs
export RUSTFS_OBS_LOGGER_LEVEL=info
export RUSTFS_OBS_LOG_KEEP_FILES=30
export RUSTFS_OBS_LOG_MAX_TOTAL_SIZE_BYTES=5368709120   # 5 GiB
./rustfs

Full OTLP pipeline (production)

export RUSTFS_OBS_ENDPOINT=http://otel-collector:4318
export RUSTFS_OBS_ENVIRONMENT=production
export RUSTFS_OBS_SAMPLE_RATIO=0.05      # 5% trace sampling
export RUSTFS_OBS_LOG_DIRECTORY=/var/log/rustfs
export RUSTFS_OBS_LOG_STDOUT_ENABLED=false
./rustfs

Separate per-signal endpoints

export RUSTFS_OBS_TRACE_ENDPOINT=http://tempo:4318/v1/traces
export RUSTFS_OBS_METRIC_ENDPOINT=http://prometheus-otel:4318/v1/metrics
export RUSTFS_OBS_LOG_ENDPOINT=http://loki-otel:4318/v1/logs
./rustfs

Dry-run cleanup audit

export RUSTFS_OBS_LOG_DIRECTORY=/var/log/rustfs
export RUSTFS_OBS_LOG_DRY_RUN=true
./rustfs
# Observe log output — no files will actually be deleted.

---

Module Structure

rustfs-obs/src/
├── lib.rs                   # Crate root; public re-exports
├── config.rs                # OtelConfig + AppConfig; env-var loading
├── error.rs                 # TelemetryError type
├── global.rs                # init_obs / init_obs_with_config entry points
│
├── telemetry/               # Backend initialisation
│   ├── mod.rs               # init_telemetry routing logic
│   ├── guard.rs             # OtelGuard RAII lifecycle manager
│   ├── filter.rs            # EnvFilter construction helpers
│   ├── resource.rs          # OTel Resource builder
│   ├── local.rs             # Stdout-only and rolling-file backends
│   ├── otel.rs              # Full OTLP/HTTP pipeline
│   └── recorder.rs          # metrics-crate → OTel bridge (Recorder)
│
├── log_cleanup/             # Background log-file cleanup subsystem
│   ├── mod.rs               # LogCleaner public API + tests
│   ├── types.rs             # FileInfo shared type
│   ├── scanner.rs           # Filesystem discovery
│   ├── compress.rs          # Gzip compression helper
│   └── cleaner.rs           # Selection, compression, deletion logic
│
└── system/                  # Host metrics (CPU, memory, disk, GPU)
    ├── mod.rs
    ├── attributes.rs
    ├── collector.rs
    ├── metrics.rs
    └── gpu.rs               # GPU metrics (feature = "gpu")

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Using LogCleaner Directly

use std::path::PathBuf;
use rustfs_obs::LogCleaner;

let cleaner = LogCleaner::new(
    PathBuf::from("/var/log/rustfs"),
    "rustfs.log.".to_string(),  // file_prefix
    10,                          // keep_count
    2 * 1024 * 1024 * 1024,      // max_total_size_bytes (2 GiB)
    0,                           // max_single_file_size_bytes (unlimited)
    true,                        // compress_old_files
    6,                           // gzip_compression_level
    30,                          // compressed_file_retention_days
    vec!["current.log".to_string()], // exclude_patterns
    true,                        // delete_empty_files
    3600,                        // min_file_age_seconds (1 hour)
    false,                       // dry_run
);

let (deleted, freed_bytes) = cleaner.cleanup().expect("cleanup failed");
println!("Deleted {deleted} files, freed {freed_bytes} bytes");

---

Feature Flags

Flag	Description
(default)	Core logging, tracing, and metrics
gpu	GPU utilisation metrics via nvml
full	All features enabled

# Enable GPU monitoring
rustfs-obs = { version = "0.0.5", features = ["gpu"] }

# Enable everything
rustfs-obs = { version = "0.0.5", features = ["full"] }

---

License

Apache 2.0 — see LICENSE.