Common answers to the common questions of Microprofile Metrics API
Common answers to the common questions of Microprofile Metrics API
Introduction:
Microprofile Metrics API is a specification for collecting application degree information.It provides a simple and lightweight way to capture and disclose data on the performance of the application during the runtime of the application, such as request counting, response time, error rate, etc.In this article, we will answer some common questions related to Microprofile Metrics API and provide some Java code examples.
Question 1: What is Microprofile Metrics API?
Answer: Microprofile Metrics API is an open specification that defines a set of interfaces and annotations to collect and disclose the operating time information of the application.It can help developers monitor and analyze the performance of the application and optimize it.
Question 2: How to use Microprofile Metrics API?
Answer: It is very simple to use Microprofile Metrics API.You only need to add related dependencies to your project, and use the annotation method and class to mark the method and class.For example, we can use the @counted annotation to calculate the number of calls and make it publicly as a measurement information.
Example code:
import org.eclipse.microprofile.metrics.annotation.Counted;
public class ExampleService {
@Counted(name = "exampleCounter", absolute = true)
public void processRequest() {
// Business logic code
}
}
Question 3: How to expose measurement information?
Answer: Microprofile Metrics API uses a core concept called MetricsRegistry, which is a central registry for managing measurement information.You can access MetricsRegistry in the application and use its method to obtain measurement information, such as counter, histogram, etc.
Example code:
import org.eclipse.microprofile.metrics.Counter;
import org.eclipse.microprofile.metrics.MetricRegistry;
import org.eclipse.microprofile.metrics.annotation.Metric;
public class ExampleService {
@Metric(absolute = true, name = "exampleCounter")
private Counter counter;
public void processRequest() {
// Business logic code
counter.inc();
}
}
Question 4: How to disclose the endpoint of information?
Answer: Microprofile Metrics API provides a MetricsSservlet, which is an HTTP endpoint for disclosing measurement information.You can configure the service to your application and then get the measurement information by sending the HTTP request.
You need to add the following configuration to the web.xml file:
<servlet>
<servlet-name>MetricsServlet</servlet-name>
<servlet-class>org.eclipse.microprofile.metrics.servlet.MetricsServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>MetricsServlet</servlet-name>
<url-pattern>/metrics/*</url-pattern>
</servlet-mapping>
Question 5: How to customize the label of measurement information?
Answer: Microprofile Metrics API allows you to add custom tags to measure information to better organize and query them.You can use the @Metric comment tags property to define the label and access it in the measurement information.
Example code:
import org.eclipse.microprofile.metrics.MetricUnits;
import org.eclipse.microprofile.metrics.annotation.Gauge;
public class ExampleService {
@Gauge(name = "exampleGauge", unit = MetricUnits.NONE, tags = {"region=us", "environment=production"})
public int getQueueSize() {
// Here the size of the queue
return queue.size();
}
}
in conclusion:
Microprofile Metrics API is a useful tool that helps developers monitor and optimize the performance of the application.By using annotations and related classes, you can easily collect and publicly measure information.In addition, you can also use MetricsSservlet to expose the measurement information into HTTP endpoints, and further segment and query the measurement information through custom tags.
