[jboss-dev-forums] [JBoss AS 7 Development] - Re: jboss-modules: Module Repository SPI and Extensibility
Andrew Rubinger
do-not-reply at jboss.com
Thu Oct 25 04:04:35 EDT 2012
Andrew Rubinger [https://community.jboss.org/people/ALRubinger] created the discussion
"Re: jboss-modules: Module Repository SPI and Extensibility"
To view the discussion, visit: https://community.jboss.org/message/772249#772249
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And Randall, just to be complete, the RepositoryModuleLoader I've been playing with looks a bit like:
/*
* JBoss, Home of Professional Open Source
* Copyright 2012, Red Hat Middleware LLC, and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jboss.modules;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashSet;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.stream.FactoryConfigurationError;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
/**
* {@link ModuleLoader} implementation which loads from a local module repository. If no matching module is found
* locally, an attempt will be made to resolve module resources from a (possibly remote) repository accessible via a
* root {@link URL}.
*
* <br />
* <br />
*
* The default location of the local module repository is located on the filesystem at
* <code>$USER_HOME/.jboss/modules/repo</code>, unless overridden by explicitly-providing a location via
* {@link RepositoryModuleLoader#create(URL, File)}. New {@link RepositoryModuleLoader} instances with the default local
* repository may be created using {@link RepositoryModuleLoader#create(URL)}.
*
* @author <a href="mailto:alr at jboss.org">Andrew Lee Rubinger</a>
*/
public final class RepositoryModuleLoader extends ModuleLoader {
private static final Logger log = Logger.getLogger(RepositoryModuleLoader.class.getName());
private static final String DEFAULT_NAME_REPOSITORY = ".jboss" + File.separatorChar + "modules"
+ File.separatorChar + "repo";
private static final File USER_HOME_DIR = new File(SecurityActions.getSystemProperty("user.home"));
private static final File DEFAULT_LOCAL_REPO = new File(USER_HOME_DIR, DEFAULT_NAME_REPOSITORY);
private static final String NAME_MODULES_DESCRIPTOR = "module.xml";
private static final String ELEMENT_NAME_RESOURCE_ROOT = "resource-root";
private static final String ELEMENT_NAME_DEPENDENCIES = "dependencies";
private static final String ELEMENT_NAME_MODULE = "module";
private static final String ATTRIBUTE_NAME_PATH = "path";
private static final String ATTRIBUTE_NAME_NAME = "name";
private static final String SUFFIX_INDEX = ".index";
/**
* Root of the (possibly) remote repository from which to fetch modules
*/
private final URL rootUrl;
/**
* Root of the local module repository
*/
final File localRepoRoot;
/**
* Delegate used to load modules from the local module repository
*/
private final LocalModuleLoader localDelegate;
/**
* Creates a new instance using the specified root {@link URL} for the backing repository and the specified
* {@link File} root for the local repository. Both arguments are required, and the local repository root must both
* exist and be a directory, else {@link IllegalArgumentException} will be raised.
*
* @param rootUrl
* @param localRepoRoot
*/
private RepositoryModuleLoader(final URL rootUrl, final File localRepoRoot) throws IllegalArgumentException {
if (rootUrl == null) {
throw new IllegalArgumentException("Root URL must be specified");
}
if (localRepoRoot == null) {
throw new IllegalArgumentException("Local Repository Root must be specified");
}
if (!localRepoRoot.exists()) {
throw new IllegalArgumentException("Local Repository Root must exist: " + localRepoRoot);
}
if (!localRepoRoot.isDirectory()) {
throw new IllegalArgumentException("Local Repository Root must be a directory: " + localRepoRoot);
}
this.localRepoRoot = localRepoRoot;
this.rootUrl = rootUrl;
this.localDelegate = new LocalModuleLoader(new File[] { localRepoRoot.getAbsoluteFile() });
}
/**
* Creates a new {@link RepositoryModuleLoader} instance using the specified root URL from which to fetch modules
* and the specified local repository root to cache downloaded modules.
*
* @param rootUrl
* @param localRepoRoot
* @return
* @throws IllegalArgumentException
* If either argument is not specified, or if the local repository root does not exist or is not a
* directory
*/
public static RepositoryModuleLoader create(final URL rootUrl, final File localRepoRoot)
throws IllegalArgumentException {
return new RepositoryModuleLoader(rootUrl, localRepoRoot);
}
/**
* Creates a new {@link RepositoryModuleLoader} instance using the specified root URL from which to fetch modules
* and the default local repository root (USER_HOME_DIR/.jboss/modules/repo) to cache downloaded modules.
*
* @param rootUrl
* @return
* @throws IllegalArgumentException
* If the root {@link URL} is not specified
*/
public static RepositoryModuleLoader create(final URL rootUrl) throws IllegalArgumentException {
// Create default local repo if it doesn't exist
if (!DEFAULT_LOCAL_REPO.exists() && !DEFAULT_LOCAL_REPO.mkdirs()) {
throw new RuntimeException("Could not create default local repository: "
+ DEFAULT_LOCAL_REPO.getAbsolutePath());
}
return new RepositoryModuleLoader(rootUrl, DEFAULT_LOCAL_REPO);
}
/**
* {@inheritDoc}
*
* @see org.jboss.modules.ModuleLoader#toString()
*/
@Override
public String toString() {
return RepositoryModuleLoader.class.getSimpleName() + " with root URL: " + this.rootUrl
+ " and using local module repository root " + localRepoRoot.getAbsolutePath();
}
/**
* {@inheritDoc}
*
* @see org.jboss.modules.ModuleLoader#preloadModule(org.jboss.modules.ModuleIdentifier)
*/
@Override
protected Module preloadModule(final ModuleIdentifier identifier) throws ModuleLoadException {
Module module;
try {
module = ModuleLoader.preloadModule(identifier, localDelegate);
} catch (final ModuleNotFoundException mnfe) {
// Fetch and try again
this.fetchModuleAssets(identifier);
module = ModuleLoader.preloadModule(identifier, localDelegate);
}
// Return
return module;
}
/**
* {@inheritDoc}
*
* @see org.jboss.modules.ModuleLoader#findModule(org.jboss.modules.ModuleIdentifier)
*/
@Override
protected ModuleSpec findModule(final ModuleIdentifier moduleIdentifier) throws ModuleLoadException {
// We never load the module, the local delegate does via preloadModule
// FIXME This mechanism really breaks the stated purpose of the SPI, raise the issue to DML
throw new UnsupportedOperationException("Should never be reached, we use a delegate loader");
}
/**
* Obtains all module resources for the given (required) {@link ModuleIdentifier}. Will recurse to obtain dependent
* module assets as well.
*
* @param moduleIdentifier
*/
private void fetchModuleAssets(final ModuleIdentifier moduleIdentifier) {
assert moduleIdentifier != null : "Module identifier is required";
// Fetch the module.xml into the local modules repo
final String relativePath = toHttpPathString(moduleIdentifier);
final File localRepoModuleRoot = new File(localRepoRoot, toLocalDiskPathString(moduleIdentifier));
final File localModulesFile;
try {
localModulesFile = this.downloadToLocalRepository(relativePath, NAME_MODULES_DESCRIPTOR,
localRepoModuleRoot);
} catch (final FileNotFoundException fnfe) {
throw new RuntimeException("Could not find " + NAME_MODULES_DESCRIPTOR, fnfe);
}
// Parse out the name of the resource root and any dependencies
String resourceRootPath = null;
final Set<String> dependencies = new HashSet<String>();
final XMLStreamReader reader;
try {
reader = XMLInputFactory.newInstance().createXMLStreamReader(new FileInputStream(localModulesFile));
} catch (final FileNotFoundException fnfe) {
throw new RuntimeException("Could not find the file we've just written: "
+ localModulesFile.getAbsolutePath());
} catch (final XMLStreamException xmlse) {
throw new RuntimeException(xmlse);
} catch (final FactoryConfigurationError fce) {
throw new RuntimeException(fce);
}
try {
boolean inDependenciesSection = false;
readerLoop: while (reader.hasNext()) {
final int next = reader.next();
switch (next) {
case XMLStreamReader.START_ELEMENT:
String elementName = reader.getLocalName();
if (ELEMENT_NAME_RESOURCE_ROOT.equals(elementName)) {
final int numAttributes = reader.getAttributeCount();
for (int i = 0; i < numAttributes; i++) {
final String attribute = reader.getAttributeLocalName(i);
if (ATTRIBUTE_NAME_PATH.equals(attribute)) {
resourceRootPath = reader.getAttributeValue(i);
}
}
continue;
}
if (ELEMENT_NAME_DEPENDENCIES.equals(elementName)) {
inDependenciesSection = true;
continue;
}
if (ELEMENT_NAME_MODULE.equals(elementName) && inDependenciesSection) {
final int numAttributes = reader.getAttributeCount();
for (int i = 0; i < numAttributes; i++) {
final String attribute = reader.getAttributeLocalName(i);
if (ATTRIBUTE_NAME_NAME.equals(attribute)) {
dependencies.add(reader.getAttributeValue(i));
}
}
}
continue;
case XMLStreamReader.END_ELEMENT:
elementName = reader.getLocalName();
if (ELEMENT_NAME_DEPENDENCIES.equals(elementName)) {
break readerLoop;
}
}
}
} catch (final XMLStreamException xmlse) {
throw new RuntimeException("Encountered error reading from " + localModulesFile.getAbsolutePath(), xmlse);
}
if (resourceRootPath == null) {
// Could be to system path, so we're done here
return;
}
// Get all dependencies recursively
for (final String dependency : dependencies) {
final ModuleIdentifier moduleId = ModuleIdentifier.fromString(dependency);
this.fetchModuleAssets(moduleId);
}
// Download the resource root
try {
this.downloadToLocalRepository(relativePath, resourceRootPath, localRepoModuleRoot);
} catch (final FileNotFoundException fnfe) {
throw new RuntimeException("Specified resource root could not be found: " + resourceRootPath);
}
// Download the index file
final String indexFileName = resourceRootPath + SUFFIX_INDEX;
try {
this.downloadToLocalRepository(relativePath, indexFileName, localRepoModuleRoot);
} catch (final FileNotFoundException fnfe) {
// Ignore, must be no index
if (log.isLoggable(Level.FINEST)) {
log.finest("No index file found: " + indexFileName + "; skipping.");
}
}
}
/**
* Performs the download of the remote file name located in the relative remote path to the specified parent
* directory. All arguments are required.
*
* @param relativeRemotePath
* @param remoteFileName
* @param parentDir
* @return
* @throws FileNotFoundException
* If the requested resource could not be found in the remote path with the remote file name
*/
private File downloadToLocalRepository(final String relativeRemotePath, final String remoteFileName,
final File parentDir) throws FileNotFoundException {
assert relativeRemotePath != null;
assert remoteFileName != null;
assert parentDir != null;
final URL relativePathURL;
final URL fullURL;
try {
relativePathURL = new URL(rootUrl, relativeRemotePath);
fullURL = new URL(relativePathURL, remoteFileName);
} catch (final MalformedURLException murle) {
throw new RuntimeException(murle);
}
final File targetFile = new File(parentDir, remoteFileName);
final InputStream in;
try {
if (log.isLoggable(Level.INFO)) {
log.info("Writing: " + fullURL + " as " + targetFile);
}
in = fullURL.openStream();
} catch (final IOException ioe) {
throw new RuntimeException("Could not get stream to " + fullURL.toExternalForm(), ioe);
}
if (in == null) {
throw new FileNotFoundException("Could not find requested file at URL: " + fullURL.toExternalForm());
}
if (!parentDir.exists() && !parentDir.mkdirs()) {
throw new IllegalStateException("Could not create parent directory: " + parentDir);
}
OutputStream out = null;
try {
try {
out = new FileOutputStream(targetFile);
} catch (final FileNotFoundException fnfe) {
throw new RuntimeException(fnfe);
}
final byte[] buffer = new byte[512]; // Relatively smaller buffer as we don't know how far away the
// source is
try {
int readBytes = 0;
while ((readBytes = in.read(buffer)) != -1) {
out.write(buffer, 0, readBytes);
if (log.isLoggable(Level.INFO)) {
// Only way to show incremental progress without flooding the log with unnecessary lines is to
// write straight to console
System.out.print('.');
}
}
if (log.isLoggable(Level.INFO)) {
System.out.println();
}
} catch (final IOException ioe) {
throw new RuntimeException(ioe);
}
} finally {
try {
if (out != null) {
out.close();
if (log.isLoggable(Level.INFO)) {
log.info("Wrote " + targetFile.getAbsolutePath());
}
}
} catch (final IOException ioe) {
// Swallow
}
}
// Return
return targetFile;
}
private static String toHttpPathString(final ModuleIdentifier moduleIdentifier) {
return toPathString(moduleIdentifier, '/');
}
private static String toLocalDiskPathString(final ModuleIdentifier moduleIdentifier) {
return toPathString(moduleIdentifier, File.separatorChar);
}
private static String toPathString(final ModuleIdentifier moduleIdentifier, final char replacementChar) {
final StringBuilder builder = new StringBuilder(40);
builder.append(moduleIdentifier.getName().replace('.', replacementChar));
builder.append(replacementChar).append(moduleIdentifier.getSlot());
builder.append(replacementChar);
return builder.toString();
}
}
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