dlmarion commented on code in PR #51: URL: https://github.com/apache/accumulo-classloaders/pull/51#discussion_r2712496730
########## modules/hdfs-urlstreamhandler-provider/src/main/java/org/apache/accumulo/classloader/hdfsurlstreamhandlerprovider/HdfsURLStreamHandlerProvider.java: ########## @@ -0,0 +1,98 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 + * + * https://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.apache.accumulo.classloader.hdfsurlstreamhandlerprovider; + +import static java.util.Objects.requireNonNull; + +import java.io.IOException; +import java.io.InputStream; +import java.net.URI; +import java.net.URISyntaxException; +import java.net.URL; +import java.net.URLConnection; +import java.net.URLStreamHandler; +import java.net.spi.URLStreamHandlerProvider; +import java.util.function.Supplier; + +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.FileSystem; +import org.apache.hadoop.fs.Path; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import com.google.auto.service.AutoService; +import com.google.common.base.Preconditions; +import com.google.common.base.Suppliers; + +@AutoService(URLStreamHandlerProvider.class) +public class HdfsURLStreamHandlerProvider extends URLStreamHandlerProvider { + + private static final Logger LOG = LoggerFactory.getLogger(HdfsURLStreamHandlerProvider.class); + + private static class HdfsURLConnection extends URLConnection { + + private final Supplier<Configuration> conf = Suppliers.memoize(Configuration::new); + + private InputStream is; + + public HdfsURLConnection(URL url) { + super(requireNonNull(url, "null url argument")); + Preconditions.checkArgument("hdfs".equals(url.getProtocol()), + "HdfsUrlConnection only supports hdfs: URLs"); + } + + @Override + public void connect() throws IOException { + Preconditions.checkState(is == null, "Already connected"); + LOG.debug("Connecting to {}", url); + final URI uri; + try { + uri = url.toURI(); + } catch (URISyntaxException e) { + // this came from a URL that should be RFC2396-compliant, so it shouldn't happen + throw new IllegalArgumentException(e); + } + var fs = FileSystem.get(uri, conf.get()); + is = fs.open(new Path(uri)); + } + + @Override + public InputStream getInputStream() throws IOException { + if (is == null) { + connect(); + } + return is; + } + } + + private static class HdfsURLStreamHandler extends URLStreamHandler { + @Override + protected HdfsURLConnection openConnection(URL url) throws IOException { + return new HdfsURLConnection(url); + } + } + + private final Supplier<URLStreamHandler> handler = Suppliers.memoize(HdfsURLStreamHandler::new); + + @Override + public URLStreamHandler createURLStreamHandler(String protocol) { + return protocol.equals("hdfs") ? handler.get() : null; Review Comment: I wonder if we should support other Hadoop-supported protocols: `s3a`, `viewfs`, etc.? We could explicitly exclude certain types here (`file`, `http`, `https`), then call `FileSystem.getFileSystemClass(String, Configuration)` to determine if Hadoop has a matching implementation. ########## modules/hdfs-urlstreamhandler-provider/pom.xml: ########## @@ -0,0 +1,62 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!-- + + Licensed to the Apache Software Foundation (ASF) under one + or more contributor license agreements. See the NOTICE file + distributed with this work for additional information + regarding copyright ownership. The ASF licenses this file + to you 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 + + https://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. + +--> +<project xmlns="http://maven.apache.org/POM/4.0.0"; xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd";> + <modelVersion>4.0.0</modelVersion> + <parent> + <groupId>org.apache.accumulo</groupId> + <artifactId>classloader-extras</artifactId> + <version>1.0.0-SNAPSHOT</version> + <relativePath>../../pom.xml</relativePath> + </parent> + <artifactId>hdfs-urlstreamhandler-provider</artifactId> + <name>HDFS URLStreamHandlerProvider</name> Review Comment: If we implement my suggestion above to support more Hadoop supported filesystems, then we should rename the classes, module, etc. from Hdfs* to Hadoop*. ########## modules/hdfs-urlstreamhandler-provider/src/main/java/org/apache/accumulo/classloader/hdfsurlstreamhandlerprovider/HdfsURLStreamHandlerProvider.java: ########## @@ -0,0 +1,98 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 + * + * https://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.apache.accumulo.classloader.hdfsurlstreamhandlerprovider; + +import static java.util.Objects.requireNonNull; + +import java.io.IOException; +import java.io.InputStream; +import java.net.URI; +import java.net.URISyntaxException; +import java.net.URL; +import java.net.URLConnection; +import java.net.URLStreamHandler; +import java.net.spi.URLStreamHandlerProvider; +import java.util.function.Supplier; + +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.FileSystem; +import org.apache.hadoop.fs.Path; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import com.google.auto.service.AutoService; +import com.google.common.base.Preconditions; +import com.google.common.base.Suppliers; + +@AutoService(URLStreamHandlerProvider.class) +public class HdfsURLStreamHandlerProvider extends URLStreamHandlerProvider { + + private static final Logger LOG = LoggerFactory.getLogger(HdfsURLStreamHandlerProvider.class); + + private static class HdfsURLConnection extends URLConnection { + + private final Supplier<Configuration> conf = Suppliers.memoize(Configuration::new); + + private InputStream is; + + public HdfsURLConnection(URL url) { + super(requireNonNull(url, "null url argument")); + Preconditions.checkArgument("hdfs".equals(url.getProtocol()), Review Comment: Isn't this already checked below in `createUrlStreamHandler`? -- This is an automated message from the Apache Git Service. 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