Handle custom yarn tar ball location; make yarn/dist/bin/yarn working again

README.md

@@ -140,7 +140,7 @@ present).
 Have a look at the example `POM` to see how it should be set up with Yarn: 
 https://github.com/eirslett/frontend-maven-plugin/blob/master/frontend-maven-plugin/src/it/yarn-integration/pom.xml
 
-
+For standard default node and yarn location
 ```xml
 <plugin>
     ...
@@ -165,6 +165,16 @@ https://github.com/eirslett/frontend-maven-plugin/blob/master/frontend-maven-plu
 </plugin>
 ```
 
+To specify a custom yarn dist tar ball location:
+```xml
+        <yarnDownloadUrl>https://repository.xyz.com/content/repositories/public/yarn/</yarnDownloadUrl>
+        <yarnVersion>1.17.3</yarnVersion>
+        <yarnExtension>tgz</yarnExtension>
+```
+Then the program will look for a tar file at:
+```<yarnDownloadUrl>/yarn-<yarnVersion>.tgz```, which translates to
+```https://repository.xyz.com/content/repositories/public/yarn/yarn-1.17.3.tgz```
+
 ### Running npm
 
 All node packaged modules will be installed in the `node_modules` folder in your [working directory](#working-directory).

frontend-maven-plugin/src/main/java/com/github/eirslett/maven/plugins/frontend/mojo/InstallNodeAndYarnMojo.java

@@ -31,6 +31,14 @@ public final class InstallNodeAndYarnMojo extends AbstractFrontendMojo {
         defaultValue = YarnInstaller.DEFAULT_YARN_DOWNLOAD_ROOT)
     private String yarnDownloadRoot;
 
+    /**
+     * Full path minus version to download Yarn binary from. No default. Ends with slash.
+     * Example: https://a-host.a-domain/blah/blah/-/ of  https://a-host.a-domain/blah/blah/-/yarn-1.17.3.tgz
+     */
+    @Parameter(property = "yarnDownloadUrl", required = false,
+        defaultValue = "")
+    private String yarnDownloadUrl;
+
     /**
      * The version of Node.js to install. IMPORTANT! Most Node.js version names start with 'v', for example
      * 'v0.10.18'
@@ -44,6 +52,12 @@ public final class InstallNodeAndYarnMojo extends AbstractFrontendMojo {
     @Parameter(property = "yarnVersion", required = true)
     private String yarnVersion;
 
+    /**
+     * The tarball extension of Yarn to install, something like tgz, tar.gz, etc.
+     */
+    @Parameter(property = "yarnExtension", required = false, defaultValue = "")
+    private String yarnExtension;
+
     /**
      * Server Id for download username and password
      */
@@ -81,8 +95,13 @@ public void execute(FrontendPluginFactory factory) throws InstallationException
         } else {
             factory.getNodeInstaller(proxyConfig).setNodeDownloadRoot(this.nodeDownloadRoot)
                 .setNodeVersion(this.nodeVersion).install();
-            factory.getYarnInstaller(proxyConfig).setYarnDownloadRoot(this.yarnDownloadRoot)
-                .setYarnVersion(this.yarnVersion).install();
+            if (this.yarnDownloadUrl != null && !this.yarnDownloadUrl.isEmpty()) {
+                factory.getYarnInstaller(proxyConfig).setYarnVersion(this.yarnVersion)
+                    .install(this.yarnDownloadUrl, this.yarnExtension);
+            } else {
+                factory.getYarnInstaller(proxyConfig).setYarnDownloadRoot(this.yarnDownloadRoot)
+                    .setYarnVersion(this.yarnVersion).install();
+            }
         }
     }
 

frontend-plugin-core/src/main/java/com/github/eirslett/maven/plugins/frontend/lib/YarnInstaller.java

@@ -73,6 +73,21 @@ public void install() throws InstallationException {
         }
     }
 
+    public void install(String yarnDownloadUrl, String yarnExtension) throws InstallationException {
+        if (yarnVersion == null || yarnVersion.isEmpty()) {
+            throw new InstallationException("yarnVersion has to be provided.");
+        }
+        if (yarnExtension == null || yarnExtension.isEmpty()) {
+            throw new InstallationException("yarnExtension has to be provided.");
+        }
+        // use static lock object for a synchronized block
+        synchronized (LOCK) {
+            if (!yarnIsAlreadyInstalled()) {
+                installYarn(yarnDownloadUrl, yarnVersion, yarnExtension);
+            }
+        }
+    }
+
     private boolean yarnIsAlreadyInstalled() {
         try {
             YarnExecutorConfig executorConfig = new InstallYarnExecutorConfig(config);
@@ -97,15 +112,27 @@ private boolean yarnIsAlreadyInstalled() {
     }
 
     private void installYarn() throws InstallationException {
+        String downloadUrl = yarnDownloadRoot + yarnVersion;
+        String defaultYarnExtension = "tar.gz";
+
+        try {
+            File installDirectory = getInstallDirectory();
+            ensureCorrectYarnRootDirectory(installDirectory, yarnVersion);
+        } catch (IOException e) {
+            throw new InstallationException("Could not extract the Yarn archive", e);
+        }
+
+        installYarn(downloadUrl, yarnVersion, defaultYarnExtension);
+    }
+
+    private void installYarn(String yarnDownloadUrl, String yarnVersion, String yarnExtension) throws InstallationException {
         try {
             logger.info("Installing Yarn version {}", yarnVersion);
-            String downloadUrl = yarnDownloadRoot + yarnVersion;
-            String extension = "tar.gz";
-            String fileending = "/yarn-" + yarnVersion + "." + extension;
+            String fileEnding = "/yarn-" + yarnVersion + "." + yarnExtension;
 
-            downloadUrl += fileending;
+            String downloadUrl = yarnDownloadUrl + fileEnding;
 
-            CacheDescriptor cacheDescriptor = new CacheDescriptor("yarn", yarnVersion, extension);
+            CacheDescriptor cacheDescriptor = new CacheDescriptor("yarn", yarnVersion, yarnExtension);
 
             File archive = config.getCacheResolver().resolve(cacheDescriptor);
 
@@ -141,8 +168,6 @@ private void installYarn() throws InstallationException {
                 throw e;
             }
 
-            ensureCorrectYarnRootDirectory(installDirectory, yarnVersion);
-
             logger.info("Installed Yarn locally.");
         } catch (DownloadException e) {
             throw new InstallationException("Could not download Yarn", e);
@@ -160,9 +185,45 @@ private File getInstallDirectory() {
         return installDirectory;
     }
 
-    private void extractFile(File archive, File destinationDirectory) throws ArchiveExtractionException {
+    private File getDistDirectory(File destinationDirectory) throws IOException {
+        File distDirectory = new File(destinationDirectory,  "dist");
+        if (distDirectory.exists()) {
+            try {
+                FileUtils.deleteDirectory(distDirectory);
+            } catch (IOException e) {
+                throw new IOException("Could not clean up existing dist directory:  " + distDirectory.getName());
+            }
+        }
+        logger.info("Creating directory {}", distDirectory);
+        distDirectory.mkdir();
+        return distDirectory;
+    }
+
+    private void copyToDist(File destinationDirectory) throws IOException {
+        // Copying installed /node/yarn/yarn-<version> to /node/yarn/dist for execution path.
+        // See this: https://github.com/eirslett/frontend-maven-plugin/issues/647
+        File versionedDirectory = new File(destinationDirectory, "yarn-" +
+            (yarnVersion.startsWith("v") ? "" : "v") +
+            yarnVersion);
+        File distDirectory = getDistDirectory(destinationDirectory);
+
+        if (versionedDirectory.exists()) {
+            try {
+                logger.info("Copying {} to {}", versionedDirectory, distDirectory);
+                FileUtils.copyDirectory(versionedDirectory, distDirectory, true);
+                File distYarn = new File(distDirectory, "bin/yarn");
+                distYarn.setExecutable(true);
+            } catch (IOException e) {
+                logger.error("Failed to copy from {} to {}.", versionedDirectory, distDirectory);
+            }
+        }
+    }
+
+    private void extractFile(File archive, File destinationDirectory) throws ArchiveExtractionException, IOException {
         logger.info("Unpacking {} into {}", archive, destinationDirectory);
         archiveExtractor.extract(archive.getPath(), destinationDirectory.getPath());
+        copyToDist(destinationDirectory);
+
     }
 
     private void ensureCorrectYarnRootDirectory(File installDirectory, String yarnVersion) throws IOException {