Add JENKINS_UC_DOWNLOAD_URL for custom update center url

README.md

@@ -70,9 +70,12 @@ Jenkins in a broken state.
 * `CACHE_DIR`: used to configure the directory where the plugins update center cache is located. By default it will be in `~/.cache/jenkins-plugin-management-cli`,
 if the user doesn't have a home directory when it will go to: `$(pwd)/.cache/jenkins-plugin-management-cli`.
 
-* `JENKINS_UC_DOWNLOAD`: used to configure the URL from where plugins will be downloaded from. Often used to cache or to proxy the Jenkins plugin download site. 
-If set then all plugins will be downloaded through that URL.
-
+* `JENKINS_UC_DOWNLOAD`: used to configure the URL from where plugins will be downloaded from. When this value is set, it replaces the plugin download URL found in the `update-center.json` file with `${JENKINS_UC_DOWNLOAD}/plugins`. Often used to cache or to proxy the Jenkins plugin download site.
+If set then all plugins will be downloaded through that URL. To use a custom URL, use `JENKINS_UD_DOWNLOAD_URL`.
+
+* `JENKINS_UC_DOWNLOAD_URL`: used to configure a custom URL from where plugins will be downloaded from. When this value is set, it replaces the plugin download URL found in the `update-center.json` file with `${JENKINS_UC_DOWNLOAD_URL}`. Often used to cache or to proxy the Jenkins plugin download site.
+If set then all plugins will be downloaded through that URL. To use a conventional download center url, use `JENKINS_UD_DOWNLOAD`.
+
 * `JENKINS_UC_HASH_FUNCTION`: used to configure the hash function which checks content from UCs. Currently `SHA1` (deprecated), `SHA256` (default), and `SHA512` can be specified.
 
 #### Plugin Input Format

plugin-management-library/pom.xml

@@ -70,6 +70,12 @@
           <version>2.31.0</version>
           <scope>test</scope>
         </dependency>
+        <dependency>
+             <groupId>com.github.stefanbirkner</groupId>
+             <artifactId>system-rules</artifactId>
+             <version>1.19.0</version>
+             <scope>test</scope>
+         </dependency>
     </dependencies>
 
     <build>

plugin-management-library/src/main/java/io/jenkins/tools/pluginmanager/impl/PluginManager.java

@@ -1169,8 +1169,11 @@ public String getPluginDownloadUrl(Plugin plugin) {
         }
 
         String jenkinsUcDownload =  System.getenv("JENKINS_UC_DOWNLOAD");
+        String jenkinsUcDownloadUrl = System.getenv("JENKINS_UC_DOWNLOAD_URL");
         if (StringUtils.isNotEmpty(pluginUrl)) {
             urlString = pluginUrl;
+        } else if (StringUtils.isNotEmpty(jenkinsUcDownloadUrl)) {
+            urlString = appendPathOntoUrl(jenkinsUcDownloadUrl, pluginName, pluginVersion, pluginName + ".hpi");
         } else if (StringUtils.isNotEmpty(jenkinsUcDownload)) {
             urlString = appendPathOntoUrl(jenkinsUcDownload, "/plugins", pluginName, pluginVersion, pluginName + ".hpi");
         } else if ((pluginVersion.equals("latest") || plugin.isLatest()) && !StringUtils.isEmpty(jenkinsUcLatest)) {

plugin-management-library/src/test/java/io/jenkins/tools/pluginmanager/impl/PluginManagerTest.java

@@ -20,6 +20,7 @@
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
+import org.junit.contrib.java.lang.system.EnvironmentVariables;
 import org.junit.rules.TemporaryFolder;
 
 import static com.github.stefanbirkner.systemlambda.SystemLambda.tapSystemOutNormalized;
@@ -48,6 +49,10 @@ public class PluginManagerTest {
     @Rule
     public final TemporaryFolder folder = new TemporaryFolder();
 
+
+    @Rule
+    public final EnvironmentVariables environmentVariables = new EnvironmentVariables();
+
     @Before
     public void setUp() {
         cfg = Config.builder()
@@ -1104,6 +1109,10 @@ public void getPluginDownloadUrlTest() {
         String otherURL = dirName(cfg.getJenkinsUc().toString()) +
                 "download/plugins/pluginName/otherversion/pluginName.hpi";
         assertThat(pm.getPluginDownloadUrl(pluginOtherVersion)).isEqualTo(otherURL);
+
+        Plugin pluginUrlOverride = new Plugin("pluginName", "pluginVersion", "https://mirror.server.com/path/pluginName/pluginVersion/pluginName.hpi", null);
+        environmentVariables.set("JENKINS_UC_DOWNLOAD_URL", "https://server.com/jenkins-plugins");
+        assertThat(pm.getPluginDownloadUrl(pluginUrlOverride)).isEqualTo("https://server.com/jenkins-plugins/pluginName/pluginVersion/pluginName.hpi");
     }
 
     @Test