Implementation:Ray project Ray MetricConfig

Knowledge Sources	Ray
Domains	Observability, Metrics
Last Updated	2026-02-13 16:00 GMT

Overview

The MetricConfig class is an immutable configuration object that controls the behavior of the Ray Java metric reporting scheduler.

Description

MetricConfig defines three configuration parameters for the metric registry: the reporting time interval, the thread pool size for the scheduler, and the shutdown wait time. It provides sensible defaults (5-second interval, 1 thread, 3-second shutdown wait) through a static DEFAULT_CONFIG instance. A nested MetricConfigBuilder class implements the builder pattern for creating custom configurations.

Usage

Use MetricConfig when you need to customize the metric reporting behavior, such as adjusting the flush interval or thread pool size. For most cases, the DEFAULT_CONFIG is sufficient. Pass a MetricConfig instance to Metrics.init() to initialize the metric registry with custom settings.

Code Reference

Source Location

• Repository: Ray
• File: java/runtime/src/main/java/io/ray/runtime/metric/MetricConfig.java

Signature

public class MetricConfig {
    public static final MetricConfig DEFAULT_CONFIG;

    public MetricConfig(long timeIntervalMs, int threadPoolSize, long shutdownWaitTimeMs)
    public long timeIntervalMs()
    public int threadPoolSize()
    public long shutdownWaitTimeMs()
    public String toString()
    public static MetricConfigBuilder builder()

    public static class MetricConfigBuilder {
        public MetricConfig create()
        public MetricConfigBuilder timeIntervalMs(long timeIntervalMs)
        public MetricConfigBuilder threadPoolSize(int threadPoolSize)
        public MetricConfigBuilder shutdownWaitTimeMs(long shutdownWaitTimeMs)
    }
}

Import

import io.ray.runtime.metric.MetricConfig;

I/O Contract

Constructor Parameters
Name	Type	Required	Description
timeIntervalMs	long	Yes	Time interval in milliseconds between metric flushes to the native stats system
threadPoolSize	int	Yes	Number of threads in the scheduled executor pool for metric reporting
shutdownWaitTimeMs	long	Yes	Maximum time in milliseconds to wait for the scheduler to shut down gracefully

Accessor Methods
Method	Return Type	Default Value	Description
timeIntervalMs()	long	5000	Returns the reporting interval in milliseconds
threadPoolSize()	int	1	Returns the thread pool size
shutdownWaitTimeMs()	long	3000	Returns the shutdown wait time in milliseconds

Default Constants
Constant	Value	Description
DEFAULT_TIME_INTERVAL_MS	5000	Default flush interval (5 seconds)
DEFAULT_THREAD_POLL_SIZE	1	Default number of scheduler threads
DEFAULT_SHUTDOWN_WAIT_TIME_MS	3000	Default shutdown grace period (3 seconds)

Builder Methods
Method	Parameter	Return Type	Description
builder()	none	MetricConfigBuilder	Static factory method to create a new builder
timeIntervalMs(long)	timeIntervalMs	MetricConfigBuilder	Sets the reporting interval
threadPoolSize(int)	threadPoolSize	MetricConfigBuilder	Sets the thread pool size
shutdownWaitTimeMs(long)	shutdownWaitTimeMs	MetricConfigBuilder	Sets the shutdown wait time
create()	none	MetricConfig	Builds and returns the immutable configuration object

Usage Examples

// Use the default configuration
MetricConfig defaultConfig = MetricConfig.DEFAULT_CONFIG;
Metrics.init(defaultConfig);

// Build a custom configuration using the builder pattern
MetricConfig customConfig = MetricConfig.builder()
    .timeIntervalMs(10000)       // Flush every 10 seconds
    .threadPoolSize(2)           // Use 2 scheduler threads
    .shutdownWaitTimeMs(5000)    // Wait 5 seconds on shutdown
    .create();

MetricRegistry registry = Metrics.init(customConfig);

// Inspect configuration values
long interval = customConfig.timeIntervalMs();    // 10000
int poolSize = customConfig.threadPoolSize();      // 2
long waitTime = customConfig.shutdownWaitTimeMs(); // 5000

Related Pages

• Environment:Ray_project_Ray_Java_Build_Environment
• Ray_project_Ray_Metrics_API - Uses MetricConfig to initialize the metric registry
• Ray_project_Ray_Metric_Base - Abstract base class for metrics managed by the configured registry