rustfs/crates/obs/README.md

rustfs-obs

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

---

Features

Feature	Description
Structured logging	JSON-formatted logs via tracing-subscriber
Rolling-file logging	Daily / hourly rotation with automatic cleanup and high-precision timestamps
Distributed tracing	OTLP/HTTP export to Jaeger, Tempo, or any OTel collector
Metrics	OTLP/HTTP export, bridged from the metrics crate facade
Continuous Profiling	CPU/Memory profiling export to Pyroscope
Log cleanup	Background task: size limits, zstd/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 + profiling)

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_PROFILING_ENDPOINT	(empty)	Dedicated profiling endpoint (e.g. Pyroscope)
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_PROFILING_EXPORT_ENABLED	true	Toggle profiling 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.log	Base filename for rolling logs. Rotated archives include a high-precision timestamp and counter. With the default RUSTFS_OBS_LOG_MATCH_MODE=suffix, names look like <timestamp>-<counter>.rustfs.log (e.g., 20231027103001.123456-0.rustfs.log); with prefix, they look like rustfs.log.<timestamp>-<counter> (e.g., rustfs.log.20231027103001.123456-0).
RUSTFS_OBS_LOG_ROTATION_TIME	hourly	Rotation granularity: minutely, hourly, or daily
RUSTFS_OBS_LOG_KEEP_FILES	30	Number of rolling files to keep (also used by cleaner)
RUSTFS_OBS_LOG_MATCH_MODE	suffix	File matching mode: prefix or suffix

Log cleanup

Variable	Default	Description
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	Compress files before deleting
RUSTFS_OBS_LOG_GZIP_COMPRESSION_LEVEL	6	Gzip level 1 (fastest) – 9 (best)
RUSTFS_OBS_LOG_COMPRESSION_ALGORITHM	zstd	Compression codec: zstd or gzip
RUSTFS_OBS_LOG_PARALLEL_COMPRESS	true	Enable work-stealing parallel compression
RUSTFS_OBS_LOG_PARALLEL_WORKERS	6	Number of cleaner worker threads
RUSTFS_OBS_LOG_ZSTD_COMPRESSION_LEVEL	8	Zstd level 1 (fastest) – 21 (best ratio)
RUSTFS_OBS_LOG_ZSTD_FALLBACK_TO_GZIP	true	Fallback to gzip when zstd compression fails
RUSTFS_OBS_LOG_ZSTD_WORKERS	1	zstdmt worker threads per compression task
RUSTFS_OBS_LOG_COMPRESSED_FILE_RETENTION_DAYS	30	Delete .gz / .zst 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	1800	How often the cleanup task runs (0.5 hours)
RUSTFS_OBS_LOG_DRY_RUN	false	Report deletions without actually removing files

---

Cleaner & Rotation Metrics

The log rotation and cleanup pipeline emits these metrics (via the metrics facade):

Metric	Type	Description
rustfs.log_cleaner.deleted_files_total	counter	Number of files deleted per cleanup pass
rustfs.log_cleaner.freed_bytes_total	counter	Bytes reclaimed by deletion
rustfs.log_cleaner.compress_duration_seconds	histogram	Compression stage duration
rustfs.log_cleaner.steal_success_rate	gauge	Work-stealing success ratio in parallel mode
rustfs.log_cleaner.runs_total	counter	Successful cleanup loop runs
rustfs.log_cleaner.run_failures_total	counter	Failed or panicked cleanup loop runs
rustfs.log_cleaner.rotation_total	counter	Successful file rotations
rustfs.log_cleaner.rotation_failures_total	counter	Failed file rotations
rustfs.log_cleaner.rotation_duration_seconds	histogram	Rotation latency
rustfs.log_cleaner.active_file_size_bytes	gauge	Current active log file size

These metrics cover compression, cleanup, and file rotation end-to-end.

Metric Semantics

• deleted_files_total and freed_bytes_total are emitted after each cleanup pass and include both normal log cleanup and expired compressed archive cleanup.
• compress_duration_seconds measures compression stage wall-clock time for both serial and parallel modes.
• steal_success_rate is updated by the parallel work-stealing path and remains at the last computed value.
• rotation_* metrics are emitted by RollingAppender and include retries; a failed final rotation increments rotation_failures_total.
• active_file_size_bytes is sampled on writes and after successful roll, so dashboards can track current active file growth.

Grafana Dashboard JSON Draft (Ready to Import)

Save this as rustfs-log-cleaner-dashboard.json, then import from Grafana UI. For Prometheus datasources, metric names are usually normalized to underscores, so rustfs.log_cleaner.deleted_files_total becomes rustfs_log_cleaner_deleted_files_total.

The same panels are now checked in at: .docker/observability/grafana/dashboards/rustfs.json (row title: Log Cleaner).

{
  "uid": "rustfs-log-cleaner",
  "title": "RustFS Log Cleaner",
  "timezone": "browser",
  "schemaVersion": 39,
  "version": 1,
  "refresh": "10s",
  "tags": ["rustfs", "observability", "log-cleaner"],
  "time": {
    "from": "now-6h",
    "to": "now"
  },
  "panels": [
    {
      "id": 1,
      "title": "Cleanup Runs / Failures",
      "type": "timeseries",
      "targets": [
        { "refId": "A", "expr": "sum(rate(rustfs_log_cleaner_runs_total[5m]))", "legendFormat": "runs/s" },
        { "refId": "B", "expr": "sum(rate(rustfs_log_cleaner_run_failures_total[5m]))", "legendFormat": "failures/s" }
      ],
      "gridPos": { "h": 8, "w": 12, "x": 0, "y": 0 }
    },
    {
      "id": 2,
      "title": "Freed Bytes / Deleted Files",
      "type": "timeseries",
      "targets": [
        { "refId": "A", "expr": "sum(rate(rustfs_log_cleaner_freed_bytes_total[15m]))", "legendFormat": "bytes/s" },
        { "refId": "B", "expr": "sum(rate(rustfs_log_cleaner_deleted_files_total[15m]))", "legendFormat": "files/s" }
      ],
      "gridPos": { "h": 8, "w": 12, "x": 12, "y": 0 }
    },
    {
      "id": 3,
      "title": "Compression P95 Latency",
      "type": "timeseries",
      "targets": [
        {
          "refId": "A",
          "expr": "histogram_quantile(0.95, sum(rate(rustfs_log_cleaner_compress_duration_seconds_bucket[5m])) by (le))",
          "legendFormat": "p95"
        }
      ],
      "gridPos": { "h": 8, "w": 12, "x": 0, "y": 8 }
    },
    {
      "id": 4,
      "title": "Rotation Success / Failure",
      "type": "timeseries",
      "targets": [
        { "refId": "A", "expr": "sum(rate(rustfs_log_cleaner_rotation_total[5m]))", "legendFormat": "rotation/s" },
        { "refId": "B", "expr": "sum(rate(rustfs_log_cleaner_rotation_failures_total[5m]))", "legendFormat": "rotation_failures/s" }
      ],
      "gridPos": { "h": 8, "w": 12, "x": 12, "y": 8 }
    },
    {
      "id": 5,
      "title": "Steal Success Rate",
      "type": "timeseries",
      "targets": [
        { "refId": "A", "expr": "max(rustfs_log_cleaner_steal_success_rate)", "legendFormat": "ratio" }
      ],
      "gridPos": { "h": 8, "w": 12, "x": 0, "y": 16 }
    },
    {
      "id": 6,
      "title": "Active File Size",
      "type": "timeseries",
      "targets": [
        { "refId": "A", "expr": "max(rustfs_log_cleaner_active_file_size_bytes)", "legendFormat": "bytes" }
      ],
      "gridPos": { "h": 8, "w": 12, "x": 12, "y": 16 }
    }
  ]
}

PromQL Templates

Use these templates directly in Grafana panels/alerts.

• Cleanup run rate
  • sum(rate(rustfs_log_cleaner_runs_total[$__rate_interval]))
• Cleanup failure rate
  • sum(rate(rustfs_log_cleaner_run_failures_total[$__rate_interval]))
• Cleanup failure ratio
  • sum(rate(rustfs_log_cleaner_run_failures_total[$__rate_interval])) / clamp_min(sum(rate(rustfs_log_cleaner_runs_total[$__rate_interval])), 1e-9)
• Freed bytes throughput
  • sum(rate(rustfs_log_cleaner_freed_bytes_total[$__rate_interval]))
• Deleted files throughput
  • sum(rate(rustfs_log_cleaner_deleted_files_total[$__rate_interval]))
• Compression p95 latency
  • histogram_quantile(0.95, sum(rate(rustfs_log_cleaner_compress_duration_seconds_bucket[$__rate_interval])) by (le))
• Rotation failure ratio
  • sum(rate(rustfs_log_cleaner_rotation_failures_total[$__rate_interval])) / clamp_min(sum(rate(rustfs_log_cleaner_rotation_total[$__rate_interval])), 1e-9)
• Work-stealing efficiency (latest)
  • max(rustfs_log_cleaner_steal_success_rate)
• Active file size (latest)
  • max(rustfs_log_cleaner_active_file_size_bytes)

Suggested Alerts

• CleanupFailureRatioHigh: failure ratio > 0.05 for 10m.
• CompressionLatencyP95High: p95 above your baseline SLO for 15m.
• RotationFailuresDetected: rotation failure rate > 0 for 3 consecutive windows.
• NoCleanupActivity: runs rate == 0 for expected active environments.

Metrics Compatibility

The project is currently in active development. Metric names and labels are updated directly when architecture evolves, and no backward-compatibility shim is maintained for old names. Use the metric names documented in this README as the current source of truth.

---

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.

Parallel zstd cleanup (recommended production profile)

export RUSTFS_OBS_LOG_DIRECTORY=/var/log/rustfs
export RUSTFS_OBS_LOG_COMPRESSION_ALGORITHM=zstd
export RUSTFS_OBS_LOG_PARALLEL_COMPRESS=true
export RUSTFS_OBS_LOG_PARALLEL_WORKERS=6
export RUSTFS_OBS_LOG_ZSTD_COMPRESSION_LEVEL=8
export RUSTFS_OBS_LOG_ZSTD_FALLBACK_TO_GZIP=true
export RUSTFS_OBS_LOG_ZSTD_WORKERS=1
./rustfs

---

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)
│
├── cleaner/                 # Background log-file cleanup subsystem
│   ├── mod.rs               # LogCleaner public API + tests
│   ├── types.rs             # Shared cleaner types (match mode, compression codec, FileInfo)
│   ├── scanner.rs           # Filesystem discovery
│   ├── compress.rs          # Gzip/Zstd compression helper
│   └── core.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")

---

Using LogCleaner Directly

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

let cleaner = LogCleaner::builder(
PathBuf::from("/var/log/rustfs"),
"rustfs.log.".to_string(),  // file_pattern
"rustfs.log".to_string(),   // active_filename
)
.match_mode(FileMatchMode::Prefix)
.keep_files(10)
.max_total_size_bytes(2 * 1024 * 1024 * 1024) // 2 GiB
.max_single_file_size_bytes(0) // unlimited
.compress_old_files(true)
.gzip_compression_level(6)
.compressed_file_retention_days(7)
.exclude_patterns(vec!["current.log".to_string()])
.delete_empty_files(true)
.min_file_age_seconds(3600) // 1 hour
.dry_run(false)
.build();

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.