Improved WARC export of Fetcher:

- optionally deduplicate records (duplicates caused by redirects)
- set WARC capture time to fetch start/end time

src/java/org/apache/nutch/fetcher/Fetcher.java

@@ -678,7 +678,6 @@ public FetcherThread(Configuration conf) {
       outlinksIgnoreExternal = conf.getBoolean("fetcher.follow.outlinks.ignore.external", false);
       maxOutlinkDepthNumLinks = conf.getInt("fetcher.follow.outlinks.num.links", 4);
       outlinksDepthDivisor = conf.getInt("fetcher.follow.outlinks.depth.divisor", 2);
-      storingWarc = conf.getBoolean("fetcher.store.warc", false);
       storing404s = conf.getBoolean("fetcher.store.404s", false);
 
       if (conf.getBoolean("fetcher.store.robotstxt", false)) {
@@ -1253,6 +1252,7 @@ public void configure(JobConf job) {
     this.segmentName = job.get(Nutch.SEGMENT_NAME_KEY);
     this.storingContent = isStoringContent(job);
     this.parsing = isParsing(job);
+    this.storingWarc = isStoringWarc(job);
 
 //    if (job.getBoolean("fetcher.verbose", false)) {
 //      LOG.setLevel(Level.FINE);
@@ -1269,6 +1269,10 @@ public static boolean isStoringContent(Configuration conf) {
     return conf.getBoolean("fetcher.store.content", true);
   }
 
+  public static boolean isStoringWarc(Configuration conf) {
+    return conf.getBoolean("fetcher.store.warc", true);
+  }
+
   public void run(RecordReader<Text, CrawlDatum> input,
       OutputCollector<Text, NutchWritable> output,
                   Reporter reporter) throws IOException {

src/java/org/apache/nutch/fetcher/FetcherOutputFormat.java

@@ -18,6 +18,10 @@
 package org.apache.nutch.fetcher;
 
 import java.io.IOException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+import java.util.TimeZone;
 
 import org.apache.nutch.crawl.CrawlDatum;
 import org.apache.nutch.crawl.NutchWritable;
@@ -44,6 +48,7 @@
 import org.commoncrawl.warc.WarcCompleteData;
 import org.commoncrawl.warc.WarcOutputFormat;
 
+
 /** Splits FetcherOutput entries into multiple map files. */
 public class FetcherOutputFormat implements OutputFormat<Text, NutchWritable> {
 
@@ -93,9 +98,24 @@ public RecordWriter<Text, NutchWritable> getRecordWriter(final FileSystem fs,
             parseOut = new ParseOutputFormat().getRecordWriter(fs, job, name, progress);
           }
 
-          if (true) { // TODO: writeWarc
-          Path warc = new Path(
-              new Path(FileOutputFormat.getOutputPath(job), "warc"), name);
+          if (Fetcher.isStoringWarc(job)) {
+            Path warc = new Path(
+                new Path(FileOutputFormat.getOutputPath(job), "warc"), name);
+            // set start and end time of WARC capture
+            long timelimit = job.getLong("fetcher.timelimit", -1);
+            long timelimitMins = job.getLong("fetcher.timelimit.mins", -1);
+            long startTime = System.currentTimeMillis();
+            long endTime = System.currentTimeMillis();
+            if (timelimitMins > 0) {
+                startTime = timelimit - (timelimitMins * 60 * 1000);
+                if (endTime > timelimit) {
+                  endTime = timelimit;
+                }
+            }
+            SimpleDateFormat fileDate = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US);
+            fileDate.setTimeZone(TimeZone.getTimeZone("GMT"));
+            job.set("warc.export.date", fileDate.format(new Date(startTime)));
+            job.set("warc.export.date.end", fileDate.format(new Date(endTime)));
             warcOut = new WarcOutputFormat().getRecordWriter(job, warc);
           }
         }

src/java/org/commoncrawl/tools/WarcExport.java

@@ -109,23 +109,13 @@ public static class ParseDataCombinedInputFormat extends CombineSequenceFileInpu
   public static class CrawlDatumCombinedInputFormat extends CombineSequenceFileInputFormat<Text, CrawlDatum> {
   }
 
-  public String getHostname() {
-    try {
-      return InetAddress.getLocalHost().getHostName();
-    } catch (UnknownHostException e) {
-      LOG.warn("Failed to get hostname: {}", e.getMessage());
-    }
-    return "localhost";
-  }
-
   public void export(Path outputDir, List<Path> segments,
       boolean generateCrawlDiagnostics, boolean generateRobotsTxt, Path cdxPath)
       throws IOException {
     Configuration conf = getConf();
 
     // We compress ourselves, so this isn't necessary
     conf.setBoolean(org.apache.hadoop.mapreduce.lib.output.FileOutputFormat.COMPRESS, false);
-    conf.set("warc.export.hostname", getHostname());
 
     conf.setBoolean("warc.export.crawldiagnostics", generateCrawlDiagnostics);
     conf.setBoolean("warc.export.robotstxt", generateRobotsTxt);

src/java/org/commoncrawl/warc/WarcOutputFormat.java

@@ -3,8 +3,10 @@
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.lang.invoke.MethodHandles;
+import java.net.InetAddress;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.net.UnknownHostException;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -69,20 +71,23 @@ protected static class WarcRecordWriter extends RecordWriter<Text, WarcCompleteD
     private boolean generateCrawlDiagnostics;
     private boolean generateRobotsTxt;
     private boolean generateCdx;
+    private String lastURL = ""; // for deduplication
+    private boolean deduplicate;
 
     public WarcRecordWriter(Configuration conf, Path outputPath,
-        String filename, String hostname,
-        String publisher, String operator, String software, String isPartOf,
-        String description,
+        String filename, String hostname, String publisher, String operator,
+        String software, String isPartOf, String description,
         boolean generateCrawlDiagnostics, boolean generateRobotsTxt,
-        boolean generateCdx, Path cdxPath, Date captureStartDate)
-        throws IOException {
+        boolean generateCdx, Path cdxPath, Date captureStartDate,
+        boolean deduplicate) throws IOException {
 
       FileSystem fs = outputPath.getFileSystem(conf);
 
       Path warcPath = new Path(new Path(outputPath, "warc"), filename);
       warcOut = fs.create(warcPath);
 
+      this.deduplicate = deduplicate;
+
       this.generateCdx = generateCdx;
       if (generateCdx) {
         cdxOut = openCdxOutputStream(new Path(cdxPath, "warc"), filename, conf);
@@ -169,8 +174,9 @@ protected static DataOutputStream openCdxOutputStream(Path cdxPath,
     public synchronized void write(Text key, WarcCompleteData value) throws IOException {
       URI targetUri;
 
+      String url = value.url.toString();
       try {
-        targetUri = new URI(value.url.toString());
+        targetUri = new URI(url);
       } catch (URISyntaxException e) {
         LOG.error("Cannot write WARC record, invalid URI: {}", value.url);
         return;
@@ -181,6 +187,14 @@ public synchronized void write(Text key, WarcCompleteData value) throws IOExcept
         return;
       }
 
+      if (deduplicate) {
+        if (lastURL.equals(url)) {
+          LOG.info("Skipping duplicate record: {}", value.url);
+          return;
+        }
+        lastURL = url;
+      }
+
       String ip = "0.0.0.0";
       Date date = null;
       boolean notModified = false;
@@ -456,7 +470,7 @@ public RecordWriter<Text, WarcCompleteData> getRecordWriter(
           e.getMessage());
     }
 
-    String hostname = conf.get("warc.export.hostname", "localhost");
+    String hostname = conf.get("warc.export.hostname", getHostname());
     String publisher = conf.get("warc.export.publisher", null);
     String operator = conf.get("warc.export.operator", null);
     String software = conf.get("warc.export.software", null);
@@ -465,6 +479,7 @@ public RecordWriter<Text, WarcCompleteData> getRecordWriter(
     boolean generateCrawlDiagnostics = conf.getBoolean("warc.export.crawldiagnostics", false);
     boolean generateRobotsTxt = conf.getBoolean("warc.export.robotstxt", false);
     boolean generateCdx= conf.getBoolean("warc.export.cdx", false);
+    boolean deduplicate = conf.getBoolean("warc.deduplicate", false);
 
     // WARC recommends - Prefix-Timestamp-Serial-Crawlhost.warc.gz
     //   https://github.com/iipc/warc-specifications/blob/gh-pages/specifications/warc-format/warc-1.1/index.md#annex-b-informative-warc-file-size-and-name-recommendations
@@ -482,7 +497,7 @@ public RecordWriter<Text, WarcCompleteData> getRecordWriter(
 
     return new WarcRecordWriter(conf, outputPath, filename, hostname, publisher,
         operator, software, isPartOf, description, generateCrawlDiagnostics,
-        generateRobotsTxt, generateCdx, cdxPath, captureStartDate);
+        generateRobotsTxt, generateCdx, cdxPath, captureStartDate, deduplicate);
   }
 
   @Override
@@ -512,4 +527,14 @@ public void checkOutputSpecs(JobContext job) throws FileAlreadyExistsException,
     TokenCache.obtainTokensForNamenodes(job.getCredentials(),
         new Path[] { outDir }, job.getConfiguration());
   }
+
+  public String getHostname() {
+    try {
+      return InetAddress.getLocalHost().getHostName();
+    } catch (UnknownHostException e) {
+      LOG.warn("Failed to get hostname: {}", e.getMessage());
+    }
+    return "localhost";
+  }
+
 }