Nutch版本：Nutch 2.3

1.bin/crawl脚本
2.bin/nutch脚本

#!/bin/bash
# The Crawl command script : crawl <seedDir> <crawlId> <solrURL> <numberOfRounds>
#
# 下面这一段主要是判断bin/crawl命令的参数
#
# UNLIKE THE NUTCH ALL-IN-ONE-CRAWL COMMAND THIS SCRIPT DOES THE LINK INVERSION AND 
# INDEXING FOR EACH BATCH

SEEDDIR="$1"
CRAWL_ID="$2"
if [ "$#" -eq 3 ]; then
	LIMIT="$3"
elif [ "$#" -eq 4 ]; then
	 SOLRURL="$3"
 	LIMIT="$4"
else
	echo "Unknown # of arguments $#"
	echo "Usage: crawl <seedDir> <crawlID> [<solrUrl>] <numberOfRounds>"
	exit -1;
fi

if [ "$SEEDDIR" = "" ]; then
	echo "Missing seedDir : crawl <seedDir> <crawlID> [<solrURL>] <numberOfRounds>"
	exit -1;
fi

if [ "$CRAWL_ID" = "" ]; then
	echo "Missing crawlID : crawl <seedDir> <crawlID> [<solrURL>] <numberOfRounds>"
	exit -1;
fi

if [ "$SOLRURL" = "" ]; then
	echo "No SOLRURL specified. Skipping indexing."
fi

if [ "$LIMIT" = "" ]; then
	echo "Missing numberOfRounds : crawl <seedDir> <crawlID> [<solrURL>] <numberOfRounds>"
	exit -1;
fi

#下面的这段是可以根据实际环境需要进行配置的
#
#############################################
# MODIFY THE PARAMETERS BELOW TO YOUR NEEDS #
#############################################

# set the number of slaves nodes 设置Hadoop集群环境中Slave节点的数量
numSlaves=1

# and the total number of available tasks 分布计算的任务数
# sets Hadoop parameter "mapred.reduce.tasks"
numTasks=`expr $numSlaves \* 2`

# number of urls to fetch in one iteration
# 250K per task?
sizeFetchlist=`expr $numSlaves \* 50000`

# time limit for feching
timeLimitFetch=180

# Adds <days> to the current time to facilitate 
# crawling urls already fetched sooner then 按天设置爬取间隔 
# db.default.fetch.interval.
addDays=0
#############################################

bin="`dirname "$0"`"
bin="`cd "$bin"; pwd`"

# 根据是否存在job文件来判断是分布式或者本地运行
# determines whether mode based on presence of job file
mode=local
if [ -f "${bin}"/../*nutch*.job ]; then
	mode=distributed
fi

# Hadoop的一些参数
# note that some of the options listed here could be set in the 
# corresponding hadoop site xml param file 
commonOptions="-D mapred.reduce.tasks=$numTasks -D mapred.child.java.opts=-Xmx1000m -D mapred.reduce.tasks.speculative.execution=false -D mapred.map.tasks.speculative.execution=false -D mapred.compress.map.output=true"

# 检查是否设置Hadoop环境变量
 	# check that hadoop can be found on the path 
if [ $mode = "distributed" ]; then
 if [ $(which hadoop | wc -l ) -eq 0 ]; then
	echo "Can't find Hadoop executable. Add HADOOP_HOME/bin to the path or run in local mode."
	exit -1;
 fi
fi


function __bin_nutch {
	# run $bin/nutch, exit if exit value indicates error

	"$bin/nutch" "$@"

	RETCODE=$?
	if [ $RETCODE -ne 0 ]
	then
    	echo "Error running:"
    	echo "  $bin/nutch $@"
    	echo "Failed with exit value $RETCODE."
    	exit $RETCODE
	fi
}



# initial injection
echo "Injecting seed URLs"
__bin_nutch inject "$SEEDDIR" -crawlId "$CRAWL_ID"

# 根据LIMIT参数设置循环次数
# main loop : rounds of generate - fetch - parse - update
for ((a=1; a <= LIMIT ; a++))
do
  if [ -e ".STOP" ]
  then
   echo "STOP file found - escaping loop"
   break
  fi

  echo `date` ": Iteration $a of $LIMIT"

  echo "Generating batchId"
  batchId=`date +%s`-$RANDOM

	# 执行Generat操作
  echo "Generating a new fetchlist"
  generate_args=($commonOptions -topN $sizeFetchlist -noNorm -noFilter -adddays $addDays -crawlId "$CRAWL_ID" -batchId $batchId)
  echo "$bin/nutch generate ${generate_args[@]}"
  $bin/nutch generate "${generate_args[@]}"
  RETCODE=$?
  if [ $RETCODE -eq 0 ]; then
      : # ok: no error
  elif [ $RETCODE -eq 1 ]; then
    echo "Generate returned 1 (no new segments created)"
    echo "Escaping loop: no more URLs to fetch now"
    break
  else
    echo "Error running:"
    echo "  $bin/nutch generate ${generate_args[@]}"
    echo "Failed with exit value $RETCODE."
    exit $RETCODE
  fi

	# 执行Fetch操作
  echo "Fetching : "
  __bin_nutch fetch $commonOptions -D fetcher.timelimit.mins=$timeLimitFetch $batchId -crawlId "$CRAWL_ID" -threads 50

	# 执行Parse操作
  # parsing the batch
  echo "Parsing : "
  # enable the skipping of records for the parsing so that a dodgy document 
  # so that it does not fail the full task
  skipRecordsOptions="-D mapred.skip.attempts.to.start.skipping=2 -D mapred.skip.map.max.skip.records=1"
  __bin_nutch parse $commonOptions $skipRecordsOptions $batchId -crawlId "$CRAWL_ID"

	# 执行updatedb操作
  # updatedb with this batch
  echo "CrawlDB update for $CRAWL_ID"
  __bin_nutch updatedb $commonOptions $batchId -crawlId "$CRAWL_ID"

	
  if [ -n "$SOLRURL" ]; then
	# 执行index操作
    echo "Indexing $CRAWL_ID on SOLR index -> $SOLRURL"
    __bin_nutch index $commonOptions -D solr.server.url=$SOLRURL -all -crawlId "$CRAWL_ID"
	
	# 执行solrdedup操作
    echo "SOLR dedup -> $SOLRURL"
    __bin_nutch solrdedup $commonOptions $SOLRURL
  else
      echo "Skipping indexing tasks: no SOLR url provided."
  fi

done

exit 0

#
# The Nutch command script
#
# Environment Variables 环境变量
#
#   NUTCH_JAVA_HOME The java implementation to use.  Overrides JAVA_HOME.
#
#   NUTCH_HEAPSIZE  The maximum amount of heap to use, in MB. 
#                   Default is 1000.
#
#   NUTCH_OPTS      Extra Java runtime options.
#                   Multiple options must be separated by white space.
#
#   NUTCH_LOG_DIR   Log directory (default: $NUTCH_HOME/logs)
#
#   NUTCH_LOGFILE   Log file (default: hadoop.log)
#
#   NUTCH_CONF_DIR  Path(s) to configuration files (default: $NUTCH_HOME/conf).
#                   Multiple paths must be separated by a colon ':'.
# 
# cygwin是windows下的Linux运行环境
cygwin=false
case "`uname`" in
CYGWIN*) cygwin=true;;
esac

# resolve links - $0 may be a softlink
THIS="$0"
while [ -h "$THIS" ]; do
  ls=`ls -ld "$THIS"`
  link=`expr "$ls" : '.*-> \(.*\)$'`
  if expr "$link" : '.*/.*' > /dev/null; then
    THIS="$link"
  else
    THIS=`dirname "$THIS"`/"$link"
  fi
done

# nutch命令参数信息
# if no args specified, show usage
if [ $# = 0 ]; then
  echo "Usage: nutch COMMAND"
  echo "where COMMAND is one of:"
  echo " inject		inject new urls into the database"
  echo " hostinject     creates or updates an existing host table from a text file"
  echo " generate 	generate new batches to fetch from crawl db"
  echo " fetch 		fetch URLs marked during generate"
  echo " parse 		parse URLs marked during fetch"
  echo " updatedb 	update web table after parsing"
  echo " updatehostdb   update host table after parsing"
  echo " readdb 	read/dump records from page database"
  echo " readhostdb     display entries from the hostDB"
  echo " index          run the plugin-based indexer on parsed batches"
  echo " elasticindex   run the elasticsearch indexer - DEPRECATED use the index command instead"
  echo " solrindex 	run the solr indexer on parsed batches - DEPRECATED use the index command instead"
  echo " solrdedup 	remove duplicates from solr"
  echo " solrclean      remove HTTP 301 and 404 documents from solr - DEPRECATED use the clean command instead"
  echo " clean          remove HTTP 301 and 404 documents and duplicates from indexing backends configured via plugins"
  echo " parsechecker   check the parser for a given url"
  echo " indexchecker   check the indexing filters for a given url"
  echo " plugin 	load a plugin and run one of its classes main()"
  echo " nutchserver    run a (local) Nutch server on a user defined port"
  echo " webapp         run a local Nutch web application"
  echo " junit         	runs the given JUnit test"
  echo " or"
  echo " CLASSNAME 	run the class named CLASSNAME"
  echo "Most commands print help when invoked w/o parameters."
  exit 1
fi

# get arguments
COMMAND=$1
shift

# 根据当前目录设置NUTCH_HOME
# some directories
THIS_DIR="`dirname "$THIS"`"
NUTCH_HOME="`cd "$THIS_DIR/.." ; pwd`"

# some Java parameters
if [ "$NUTCH_JAVA_HOME" != "" ]; then
  #echo "run java in $NUTCH_JAVA_HOME"
  JAVA_HOME="$NUTCH_JAVA_HOME"
fi
  
if [ "$JAVA_HOME" = "" ]; then
  echo "Error: JAVA_HOME is not set."
  exit 1
fi


# NUTCH_JOB 
if [ -f "${NUTCH_HOME}"/*nutch*.job ]; then
  local=false
  for f in "$NUTCH_HOME"/*nutch*.job; do
    NUTCH_JOB="$f";
  done
  # cygwin path translation
  if $cygwin; then
    NUTCH_JOB="`cygpath -p -w "$NUTCH_JOB"`"
  fi
else
  local=true
fi

JAVA="$JAVA_HOME/bin/java"
JAVA_HEAP_MAX=-Xmx1000m 

# check envvars which might override default args
if [ "$NUTCH_HEAPSIZE" != "" ]; then
  #echo "run with heapsize $NUTCH_HEAPSIZE"
  JAVA_HEAP_MAX="-Xmx""$NUTCH_HEAPSIZE""m"
  #echo $JAVA_HEAP_MAX
fi

# 把NUTCH_HOME添加到CLASSPATH
# CLASSPATH initially contains $NUTCH_CONF_DIR, or defaults to $NUTCH_HOME/conf
CLASSPATH="${NUTCH_CONF_DIR:=$NUTCH_HOME/conf}"
CLASSPATH="${CLASSPATH}:$JAVA_HOME/lib/tools.jar"

# so that filenames w/ spaces are handled correctly in loops below
IFS=

# add libs to CLASSPATH
if $local; then
  for f in "$NUTCH_HOME"/lib/*.jar; do
   CLASSPATH="${CLASSPATH}:$f";
  done
  # local runtime
  # add plugins to classpath
  if [ -d "$NUTCH_HOME/plugins" ]; then
 CLASSPATH="${NUTCH_HOME}:${CLASSPATH}"
  fi
fi

# cygwin path translation
if $cygwin; then
  CLASSPATH="`cygpath -p -w "$CLASSPATH"`"
fi

# setup 'java.library.path' for native-hadoop code if necessary
# used only in local mode 
JAVA_LIBRARY_PATH=''
if [ -d "${NUTCH_HOME}/lib/native" ]; then

  JAVA_PLATFORM=`"${JAVA}" -classpath "$CLASSPATH" org.apache.hadoop.util.PlatformName | sed -e 's/ /_/g'`

  if [ -d "${NUTCH_HOME}/lib/native" ]; then
    if [ "x$JAVA_LIBRARY_PATH" != "x" ]; then
      JAVA_LIBRARY_PATH="${JAVA_LIBRARY_PATH}:${NUTCH_HOME}/lib/native/${JAVA_PLATFORM}"
    else
      JAVA_LIBRARY_PATH="${NUTCH_HOME}/lib/native/${JAVA_PLATFORM}"
    fi
  fi
fi

if [ $cygwin = true -a "X${JAVA_LIBRARY_PATH}" != "X" ]; then
  JAVA_LIBRARY_PATH="`cygpath -p -w "$JAVA_LIBRARY_PATH"`"
fi

# restore ordinary behaviour
unset IFS

# default log directory & file
if [ "$NUTCH_LOG_DIR" = "" ]; then
  NUTCH_LOG_DIR="$NUTCH_HOME/logs"
fi
if [ "$NUTCH_LOGFILE" = "" ]; then
  NUTCH_LOGFILE='hadoop.log'
fi

#Fix log path under cygwin
if $cygwin; then
  NUTCH_LOG_DIR="`cygpath -p -w "$NUTCH_LOG_DIR"`"
fi

NUTCH_OPTS=($NUTCH_OPTS -Dhadoop.log.dir="$NUTCH_LOG_DIR")
NUTCH_OPTS=("${NUTCH_OPTS[@]}" -Dhadoop.log.file="$NUTCH_LOGFILE")

if [ "x$JAVA_LIBRARY_PATH" != "x" ]; then
  NUTCH_OPTS=("${NUTCH_OPTS[@]}" -Djava.library.path="$JAVA_LIBRARY_PATH")
fi

# 根据不同的参数调用不同的类
# figure out which class to run
if [ "$COMMAND" = "crawl" ] ; then
  echo "Command $COMMAND is deprecated, please use bin/crawl instead"
  exit -1
elif [ "$COMMAND" = "inject" ] ; then
CLASS=org.apache.nutch.crawl.InjectorJob
elif [ "$COMMAND" = "hostinject" ] ; then
CLASS=org.apache.nutch.host.HostInjectorJob
elif [ "$COMMAND" = "generate" ] ; then
CLASS=org.apache.nutch.crawl.GeneratorJob
elif [ "$COMMAND" = "fetch" ] ; then
CLASS=org.apache.nutch.fetcher.FetcherJob
elif [ "$COMMAND" = "parse" ] ; then
CLASS=org.apache.nutch.parse.ParserJob
elif [ "$COMMAND" = "updatedb" ] ; then
CLASS=org.apache.nutch.crawl.DbUpdaterJob
elif [ "$COMMAND" = "updatehostdb" ] ; then
CLASS=org.apache.nutch.host.HostDbUpdateJob
elif [ "$COMMAND" = "readdb" ] ; then
CLASS=org.apache.nutch.crawl.WebTableReader
elif [ "$COMMAND" = "readhostdb" ] ; then
CLASS=org.apache.nutch.host.HostDbReader
elif [ "$COMMAND" = "elasticindex" ] ; then
CLASS=org.apache.nutch.indexer.elastic.ElasticIndexerJob
elif [ "$COMMAND" = "solrindex" ] ; then
CLASS="org.apache.nutch.indexer.IndexingJob -D solr.server.url=$1"
shift
elif [ "$COMMAND" = "index" ] ; then
CLASS=org.apache.nutch.indexer.IndexingJob
elif [ "$COMMAND" = "solrdedup" ] ; then
CLASS=org.apache.nutch.indexer.solr.SolrDeleteDuplicates
elif [ "$COMMAND" = "solrclean" ] ; then
  CLASS="org.apache.nutch.indexer.CleaningJob -D solr.server.url=$2 $1"
  shift; shift
elif [ "$COMMAND" = "clean" ] ; then
  CLASS=org.apache.nutch.indexer.CleaningJob
elif [ "$COMMAND" = "parsechecker" ] ; then
  CLASS=org.apache.nutch.parse.ParserChecker
elif [ "$COMMAND" = "indexchecker" ] ; then
  CLASS=org.apache.nutch.indexer.IndexingFiltersChecker
elif [ "$COMMAND" = "plugin" ] ; then
CLASS=org.apache.nutch.plugin.PluginRepository
elif [ "$COMMAND" = "webapp" ] ; then
CLASS=org.apache.nutch.webui.NutchUiServer
elif [ "$COMMAND" = "nutchserver" ] ; then
CLASS=org.apache.nutch.api.NutchServer
elif [ "$COMMAND" = "junit" ] ; then
  CLASSPATH="$CLASSPATH:$NUTCH_HOME/test/classes/"
  CLASS=org.junit.runner.JUnitCore
else
CLASS=$COMMAND
fi

# 判断是否分布式运行	
if $local; then
 # fix for the external Xerces lib issue with SAXParserFactory
 NUTCH_OPTS=(-Djavax.xml.parsers.DocumentBuilderFactory=com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl "${NUTCH_OPTS[@]}")
 EXEC_CALL=("$JAVA" $JAVA_HEAP_MAX "${NUTCH_OPTS[@]}" -classpath "$CLASSPATH")
else
 # check that hadoop can be found on the path
 if [ $(which hadoop | wc -l ) -eq 0 ]; then
    echo "Can't find Hadoop executable. Add HADOOP_HOME/bin to the path or run in local mode."
    exit -1;
  	 fi
 # distributed mode
 EXEC_CALL=(hadoop jar "$NUTCH_JOB")
fi

# 根据前面设置好的参数执行命令
# run it
exec "${EXEC_CALL[@]}" $CLASS "$@"