This is for NoticeTask for issue #34459

buildSrc/src/main/java/org/elasticsearch/gradle/NoticeTask.java

@@ -0,0 +1,173 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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
+ *
+ *    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.elasticsearch.gradle;
+
+import org.gradle.api.DefaultTask;
+import org.gradle.api.tasks.InputFile;
+import org.gradle.api.tasks.OutputFile;
+import org.gradle.api.tasks.TaskAction;
+
+import java.io.IOException;
+import java.io.File;
+import java.io.FileReader;
+import java.io.BufferedReader;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * A task to create a notice file which includes dependencies' notices.
+ */
+public class NoticeTask extends DefaultTask {
+    private File inputFile = getProject().getRootProject().file("NOTICE.txt");
+    private File outputFile = new File(getProject().getBuildDir(), "notices/" + getName() + "/NOTICE.txt");
+    /**
+     * Directories to include notices from
+     */
+    private List<File> licensesDirs = new ArrayList<>();
+
+    @InputFile
+    public File getInputFile() {
+        return inputFile;
+    }
+
+    public void setInputFile(File inputFile) {
+        this.inputFile = inputFile;
+    }
+
+    @OutputFile
+    public File getOutputFile() {
+        return outputFile;
+    }
+
+    public void setOutputFile(File outputFile) {
+        this.outputFile = outputFile;
+    }
+
+    public void licensesDir(File licensesDir) {
+        licensesDirs.add(licensesDir);
+    }
+
+    public List<File> getLicensesDirs() {
+        return Collections.unmodifiableList(this.licensesDirs.stream()
+                .map(file -> new File(file.toString())).collect(Collectors.toList()));
+    }
+    /**
+     * Add notices from the specified directory.
+     */
+
+    public NoticeTask() {
+        setDescription("Create a notice file from dependencies");
+        // Default licenses directory is ${projectDir}/licenses (if it exists)
+        File licensesDir = new File(getProject().getProjectDir(), "licenses");
+
+        if (licensesDir.exists()) {
+            licensesDirs.add(licensesDir);
+        }
+    }
+
+    @TaskAction
+    public void generateNotice() throws IOException {
+        final StringBuilder output = new StringBuilder();
+
+
+        try (Stream<String> lines = Files.lines(this.inputFile.toPath(), StandardCharsets.UTF_8)) {
+            lines.forEach(s -> {
+                output.append(s.trim());
+                output.append("\n");
+            });
+        }
+        output.append("\n\n");
+
+        // This is a map rather than a set so that the sort order is the 3rd
+        // party component names, unaffected by the full path to the various files
+        final Map<String, File> seen = new TreeMap<>();
+
+        licensesDirs.forEach(file -> {
+            try (Stream<Path> pathStream = Files.walk(file.toPath())) {
+                pathStream
+//                    .filter(path -> path.endsWith("-NOTICE.txt"))
+                    .filter(path -> path.toString().endsWith("-NOTICE.txt"))
+                    .map(Path::toFile)
+                    .forEach(licenseFile -> {
+                        // Here we remove the "-NOTICE.txt" so the name can be used later for the -LICENSE.txt file
+                        final String name =
+                            licenseFile.getName().substring(0, licenseFile.getName().length() - "-NOTICE.txt".length());
+
+                        if (seen.containsKey(name)) {
+                            File prevLicenseFile = seen.get(name);
+                            if (getText(prevLicenseFile).equals(getText(licenseFile)) == false) {
+                                throw new RuntimeException("Two different notices exist for dependency '" +
+                                    name + "': " + prevLicenseFile + " and " + licenseFile);
+                            }
+                        } else {
+                            seen.put(name, licenseFile);
+                        }
+                    });
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        });
+
+        for (Map.Entry<String, File> entry : seen.entrySet()) {
+            final String name = entry.getKey();
+            final File file = entry.getValue();
+            final File licenseFile = new File(file.getParentFile(), name + "-LICENSE.txt");
+
+            appendFileToOutput(file, name, "NOTICE", output);
+            appendFileToOutput(licenseFile, name, "LICENSE", output);
+        }
+
+        Files.write(outputFile.toPath(), output.toString().getBytes());
+    }
+
+    private static void appendFileToOutput(File file, final String name, final String type, StringBuilder output) {
+        String text = getText(file);
+
+        if (text.trim().isEmpty() == false) {
+            output.append("================================================================================\n");
+            output.append(name + " " + type + "\n");
+            output.append("================================================================================\n");
+            output.append(text);
+            output.append("\n\n");
+        }
+    }
+
+
+    private static String getText(File file) {
+        final StringBuilder builder = new StringBuilder();
+
+        try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
+            char[] buffer = new char[8192];
+            int read;
+
+            while ((read = reader.read(buffer)) != -1) {
+                builder.append(buffer, 0, read);
+            }
+
+        } catch (IOException e) {
+            e.printStackTrace();
+            throw new RuntimeException("Unable to read file " + file.toString());
+        }
+        return builder.toString();
+    }
+}