java 61 lines · 7 steps

Building a custom Spring Boot Actuator endpoint

A custom @Endpoint exposes build and Git metadata over Actuator, with a selector variant for querying single fields.

Explained by highlit

Spring Intermediate actuator dependency-injection observability rest-endpoint

1package com.example.actuator;
2 
3import org.springframework.beans.factory.annotation.Value;
4import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
5import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
6import org.springframework.boot.actuate.endpoint.annotation.Selector;
7import org.springframework.boot.info.BuildProperties;
8import org.springframework.boot.info.GitProperties;
9import org.springframework.stereotype.Component;
10 
11import java.time.Instant;
12import java.util.LinkedHashMap;
13import java.util.Map;
14 
15@Component
16@Endpoint(id = "release")
17public class ReleaseEndpoint {
18 
19    private final BuildProperties build;
20    private final GitProperties git;
21    private final String activeProfiles;
22 
23    public ReleaseEndpoint(BuildProperties build, GitProperties git,
24                           @Value("${spring.profiles.active:default}") String activeProfiles) {
25        this.build = build;
26        this.git = git;
27        this.activeProfiles = activeProfiles;
28    }
29 
30    @ReadOperation
31    public Map<String, Object> release() {
32        Map<String, Object> app = new LinkedHashMap<>();
33        app.put("name", build.getName());
34        app.put("version", build.getVersion());
35        app.put("artifact", build.getArtifact());
36        app.put("buildTime", build.getTime());
37        app.put("profiles", activeProfiles);
38 
39        Map<String, Object> scm = new LinkedHashMap<>();
40        scm.put("branch", git.getBranch());
41        scm.put("commit", git.getShortCommitId());
42        scm.put("commitTime", git.getCommitTime());
43        scm.put("dirty", Boolean.parseBoolean(git.get("dirty")));
44 
45        Map<String, Object> payload = new LinkedHashMap<>();
46        payload.put("application", app);
47        payload.put("git", scm);
48        payload.put("reportedAt", Instant.now());
49        return payload;
50    }
51 
52    @ReadOperation
53    public Object releaseDetail(@Selector String key) {
54        return switch (key) {
55            case "version" -> build.getVersion();
56            case "commit" -> git.getCommitId();
57            case "branch" -> git.getBranch();
58            default -> Map.of("error", "unknown key: " + key);
59        };
60    }
61}

01 / 01

STEP 01

Walkthrough

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Three takeaways

1@Endpoint plus @ReadOperation registers a custom Actuator endpoint reachable over HTTP or JMX.
2Spring Boot auto-populates BuildProperties and GitProperties from build-time metadata files.
3A @Selector parameter lets one endpoint serve both a full report and single-field lookups.

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