Add support for CircleCI

core/src/main/java/pl/project13/core/cibuild/BuildServerDataProvider.java

@@ -100,6 +100,9 @@ public static BuildServerDataProvider getBuildServerProvider(@Nonnull Map<String
     if (AzureDevOpsBuildServerData.isActiveServer(env)) {
       return new AzureDevOpsBuildServerData(log, env);
     }
+    if (CircleCiBuildServerData.isActiveServer(env)) {
+      return new CircleCiBuildServerData(log, env);
+    }
     return new UnknownBuildServerData(log, env);
   }
 

core/src/main/java/pl/project13/core/cibuild/CircleCiBuildServerData.java

@@ -0,0 +1,52 @@
+/*
+ * This file is part of git-commit-id-plugin by Konrad 'ktoso' Malawski <konrad.malawski@java.pl>
+ *
+ * git-commit-id-plugin is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * git-commit-id-plugin is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with git-commit-id-plugin.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package pl.project13.core.cibuild;
+
+import pl.project13.core.GitCommitPropertyConstant;
+import pl.project13.core.log.LoggerBridge;
+
+import javax.annotation.Nonnull;
+import java.util.Map;
+import java.util.Properties;
+
+public class CircleCiBuildServerData extends BuildServerDataProvider {
+
+  CircleCiBuildServerData(LoggerBridge log, @Nonnull Map<String, String> env) {
+    super(log,env);
+  }
+
+  /**
+   * @see <a href="https://circleci.com/docs/2.0/env-vars/#built-in-environment-variables">CircleCIBuiltInVariables</a>
+   */
+  public static boolean isActiveServer(Map<String, String> env) {
+    return env.containsKey("CIRCLECI");
+  }
+
+  @Override
+  void loadBuildNumber(@Nonnull Properties properties) {
+    String buildNumber = env.get("CIRCLE_BUILD_NUM");
+    put(properties, GitCommitPropertyConstant.BUILD_NUMBER, buildNumber == null ? "" : buildNumber);
+  }
+
+  @Override
+  public String getBuildBranch() {
+    String environmentBasedBranch = env.get("CIRCLE_BRANCH");
+    log.info("Using environment variable based branch name. CIRCLE_BRANCH = {}", environmentBasedBranch);
+    return environmentBasedBranch;
+  }
+}

core/src/main/java/pl/project13/core/cibuild/GitlabBuildServerData.java

@@ -31,10 +31,11 @@ public class GitlabBuildServerData extends BuildServerDataProvider {
   }
 
   /**
-   * @see <a href="https://docs.gitlab.com/ce/ci/variables/#predefined-variables-environment-variables">GitlabCIVariables</a>
+   * @see <a href="https://docs.gitlab.com/ce/ci/variables/predefined_variables.html">GitlabCIVariables</a>
    */
   public static boolean isActiveServer(Map<String, String> env) {
-    return env.containsKey("CI");
+    // CI is not unique to Gitlab CI (e.g. CircleCI). Use GITLAB_CI instead.
+    return env.containsKey("GITLAB_CI");
   }
 
   @Override