Extract git tags from embedded git.properties and datadog_git.properties (#8561)

* Extract git tags from embedded git.properties and datadog_git.properties

* Prioritize datadog_git.properties even in spring boot context

* Add test for ordering

* PR review: inline constants

Author: wmouchere

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/Agent.java

@@ -31,6 +31,8 @@
 import datadog.trace.api.config.UsmConfig;
 import datadog.trace.api.gateway.RequestContextSlot;
 import datadog.trace.api.gateway.SubscriptionService;
+import datadog.trace.api.git.EmbeddedGitInfoBuilder;
+import datadog.trace.api.git.GitInfoProvider;
 import datadog.trace.api.profiling.ProfilingEnablement;
 import datadog.trace.api.scopemanager.ScopeListener;
 import datadog.trace.bootstrap.benchmark.StaticEventLogger;
@@ -225,6 +227,12 @@ public static void start(
       }
     }
 
+    // Enable automatic fetching of git tags from datadog_git.properties only if CI Visibility is
+    // not enabled
+    if (!ciVisibilityEnabled) {
+      GitInfoProvider.INSTANCE.registerGitInfoBuilder(new EmbeddedGitInfoBuilder());
+    }
+
     boolean dataJobsEnabled = isFeatureEnabled(AgentFeature.DATA_JOBS);
     if (dataJobsEnabled) {
       log.info("Data Jobs Monitoring enabled, enabling spark integrations");

internal-api/src/main/java/datadog/trace/api/git/EmbeddedGitInfoBuilder.java

@@ -2,6 +2,8 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Arrays;
+import java.util.List;
 import java.util.Properties;
 import javax.annotation.Nullable;
 import org.slf4j.Logger;
@@ -11,29 +13,44 @@ public class EmbeddedGitInfoBuilder implements GitInfoBuilder {
 
   private static final Logger log = LoggerFactory.getLogger(EmbeddedGitInfoBuilder.class);
 
-  private static final String EMBEDDED_GIT_PROPERTIES_FILE_NAME = "git.properties";
-
-  private final String resourceName;
+  private final List<String> resourceNames;
 
   public EmbeddedGitInfoBuilder() {
-    this(EMBEDDED_GIT_PROPERTIES_FILE_NAME);
+    // Order is important here, from the most reliable sources to the least reliable ones
+    this(
+        Arrays.asList(
+            // Spring boot fat jars and wars should have the git.properties file in the following
+            // specific paths, guaranteeing that it's not coming from a dependency
+            "BOOT-INF/classes/datadog_git.properties",
+            "BOOT-INF/classes/git.properties",
+            "WEB-INF/classes/datadog_git.properties",
+            "WEB-INF/classes/git.properties",
+            // If we can't find the files above, probably because we're not in a spring context, we
+            // can look at the root of the classpath. Since it could be tainted by dependencies,
+            // we're looking for a specific datadog_git.properties file.
+            "datadog_git.properties"));
   }
 
-  EmbeddedGitInfoBuilder(String resourceName) {
-    this.resourceName = resourceName;
+  EmbeddedGitInfoBuilder(List<String> resourceNames) {
+    this.resourceNames = resourceNames;
   }
 
   @Override
   public GitInfo build(@Nullable String repositoryPath) {
     Properties gitProperties = new Properties();
-    try (InputStream is = ClassLoader.getSystemResourceAsStream(resourceName)) {
-      if (is != null) {
-        gitProperties.load(is);
-      } else {
-        log.debug("Could not find embedded Git properties resource: {}", resourceName);
+
+    for (String resourceName : resourceNames) {
+      try (InputStream is = ClassLoader.getSystemResourceAsStream(resourceName)) {
+        if (is != null) {
+          gitProperties.load(is);
+          // stop at the first git properties file found
+          break;
+        } else {
+          log.debug("Could not find embedded Git properties resource: {}", resourceName);
+        }
+      } catch (IOException e) {
+        log.error("Error reading embedded Git properties from {}", resourceName, e);
       }
-    } catch (IOException e) {
-      log.error("Error reading embedded Git properties from {}", resourceName, e);
     }
 
     String commitSha = gitProperties.getProperty("git.commit.id");

internal-api/src/test/groovy/datadog/trace/api/git/EmbeddedGitInfoBuilderTest.groovy

@@ -7,7 +7,7 @@ class EmbeddedGitInfoBuilderTest extends Specification {
 
   def "test no embedded git info"() {
     when:
-    def gitInfo = new EmbeddedGitInfoBuilder("non-existent-git.properties").build(null)
+    def gitInfo = new EmbeddedGitInfoBuilder(["non-existent-git.properties"]).build(null)
 
     then:
     gitInfo.isEmpty()
@@ -16,7 +16,7 @@ class EmbeddedGitInfoBuilderTest extends Specification {
   def "test maven-plugin-generated git info"() {
     when:
     def mavenGitProperties = "datadog/trace/bootstrap/git/maven-git.properties"
-    def gitInfo = new EmbeddedGitInfoBuilder(mavenGitProperties).build(null)
+    def gitInfo = new EmbeddedGitInfoBuilder([mavenGitProperties]).build(null)
 
     then:
     gitInfo.repositoryURL == "[email protected]:DataDog/ciapp-test-resources.git"
@@ -35,7 +35,7 @@ class EmbeddedGitInfoBuilderTest extends Specification {
   def "test gradle-plugin-generated git info"() {
     when:
     def gradleGitProperties = "datadog/trace/bootstrap/git/gradle-git.properties"
-    def gitInfo = new EmbeddedGitInfoBuilder(gradleGitProperties).build(null)
+    def gitInfo = new EmbeddedGitInfoBuilder([gradleGitProperties]).build(null)
 
     then:
     gitInfo.repositoryURL == "[email protected]:DataDog/ciapp-test-resources.git"
@@ -50,4 +50,13 @@ class EmbeddedGitInfoBuilderTest extends Specification {
     gitInfo.commit.committer.email == "[email protected]"
     gitInfo.commit.committer.iso8601Date == "2023-03-22T14:43:21+0100"
   }
+
+  def "test embedded gitinfo has a lower priority than user supplied gitinfo"() {
+    when:
+    def embeddedGitInfoBuilder = new EmbeddedGitInfoBuilder()
+    def userSuppliedGitInfoBuilder = new UserSuppliedGitInfoBuilder()
+
+    then:
+    embeddedGitInfoBuilder.order() > userSuppliedGitInfoBuilder.order()
+  }
 }