Struct NodeMetrics 

pub struct NodeMetrics {

    pub active_connections: Gauge,
    pub total_connections: Counter,
    pub failed_connections: Counter,
    pub messages_sent: Counter,
    pub messages_received: Counter,
    pub messages_dropped: Counter,
    pub message_size_bytes: Histogram,
    pub message_latency_ms: Histogram,
    pub state_sync_latency_ms: Histogram,
    pub memory_usage_bytes: Gauge,
    pub cpu_usage_percent: Gauge,
    pub time_drift_ms: Gauge,
    pub state_divergence_count: Gauge,
    pub quarantine_buffer_size: Gauge,
}

Core metrics for monitoring ELARA node health and performance.

This struct provides a centralized collection of all key metrics that should be monitored in a production ELARA deployment. Metrics are organized into categories:

• Connection metrics: Track connection lifecycle and health
• Message metrics: Track message throughput and reliability
• Latency metrics: Track performance characteristics
• Resource metrics: Track system resource usage
• Protocol metrics: Track protocol-specific health indicators

Example

use elara_runtime::observability::metrics::{MetricsRegistry, NodeMetrics};

let registry = MetricsRegistry::new();
let metrics = NodeMetrics::new(&registry);

// Track connections
metrics.active_connections.inc();
metrics.total_connections.inc();

// Track messages
metrics.messages_sent.inc();
metrics.message_latency_ms.observe(42.5);

// Track resources
metrics.memory_usage_bytes.set(1024 * 1024 * 512); // 512 MB
metrics.cpu_usage_percent.set(45);

Fields

active_connections: Gauge

Number of currently active connections.

total_connections: Counter

Total number of connections established since node start.

failed_connections: Counter

Total number of failed connection attempts.

messages_sent: Counter

Total number of messages sent.

messages_received: Counter

Total number of messages received.

messages_dropped: Counter

Total number of messages dropped (e.g., due to queue overflow).

message_size_bytes: Histogram

Distribution of message sizes in bytes.

message_latency_ms: Histogram

Distribution of message processing latency in milliseconds.

state_sync_latency_ms: Histogram

Distribution of state synchronization latency in milliseconds.

memory_usage_bytes: Gauge

Current memory usage in bytes.

cpu_usage_percent: Gauge

Current CPU usage as a percentage (0-100).

time_drift_ms: Gauge

Current time drift from reference time in milliseconds. Positive values indicate local clock is ahead, negative values indicate behind.

state_divergence_count: Gauge

Number of state divergences detected. This tracks instances where state reconciliation found inconsistencies.

quarantine_buffer_size: Gauge

Number of events in the quarantine buffer. Events are quarantined when they have missing dependencies.

Implementations

impl NodeMetrics

pub fn new(registry: &MetricsRegistry) -> Self

Creates a new NodeMetrics instance and registers all metrics with the provided registry.

This constructor initializes all core metrics with appropriate types and bucket configurations for histograms. All metrics are registered with the provided MetricsRegistry and can be accessed through the returned struct.

Histogram Buckets

• message_latency_ms: Buckets optimized for typical message processing times (1ms to 5 seconds)
• state_sync_latency_ms: Buckets optimized for state synchronization times (10ms to 30 seconds)
• message_size_bytes: Buckets optimized for typical message sizes (64 bytes to 1 MB)

Arguments

• registry - The metrics registry to register all metrics with

Example

use elara_runtime::observability::metrics::{MetricsRegistry, NodeMetrics};

let registry = MetricsRegistry::new();
let metrics = NodeMetrics::new(&registry);

// Metrics are now registered and ready to use
metrics.active_connections.inc();

pub fn active_connections(&self) -> &Gauge

Returns a reference to the active connections gauge.

pub fn total_connections(&self) -> &Counter

Returns a reference to the total connections counter.

pub fn failed_connections(&self) -> &Counter

Returns a reference to the failed connections counter.

pub fn messages_sent(&self) -> &Counter

Returns a reference to the messages sent counter.

pub fn messages_received(&self) -> &Counter

Returns a reference to the messages received counter.

pub fn messages_dropped(&self) -> &Counter

Returns a reference to the messages dropped counter.

pub fn message_size_bytes(&self) -> &Histogram

Returns a reference to the message size histogram.

pub fn message_latency_ms(&self) -> &Histogram

Returns a reference to the message latency histogram.

pub fn state_sync_latency_ms(&self) -> &Histogram

Returns a reference to the state sync latency histogram.

pub fn memory_usage_bytes(&self) -> &Gauge

Returns a reference to the memory usage gauge.

pub fn cpu_usage_percent(&self) -> &Gauge

Returns a reference to the CPU usage gauge.

pub fn time_drift_ms(&self) -> &Gauge

Returns a reference to the time drift gauge.

pub fn state_divergence_count(&self) -> &Gauge

Returns a reference to the state divergence count gauge.

pub fn quarantine_buffer_size(&self) -> &Gauge

Returns a reference to the quarantine buffer size gauge.

Trait Implementations

impl Clone for NodeMetrics

fn clone(&self) -> NodeMetrics

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for NodeMetrics

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.