source: gs3-extensions/maori-lang-detection/hdfs-cc-work/GS_README.TXT@ 33545

----------------------------------------
INDEX: follow in sequence
----------------------------------------
A.  VAGRANT VM WITH HADOOP AND SPARK
B.  Create IAM role on Amazon AWS to use S3a
C.  Configure Spark on your vagrant VM with the AWS authentication details
---
Script scripts/setup.sh now is automated to do the steps in D-F below
and prints out the main instruction for G.
---
D.  OPTIONAL? Further configuration for Hadoop to work with Amazon AWS
E.  Setup cc-index-table git project
F.  Setup warc-to-wet tools (git projects)
G.  Getting and running our scripts
---
H. Austici's crawl - CLI to download web sites as WARCs, features basics to avoid crawler taps
I. Setting up Nutch v2 on its own Vagrant VM machine

----------------------------------------

----------------------------------------
A. VAGRANT VM WITH HADOOP AND SPARK
----------------------------------------
Set up vagrant with hadoop and spark as follows

1. by following the instructions at
https://github.com/martinprobson/vagrant-hadoop-hive-spark

This will eventually create the following folder, which will contain Vagrantfile
/home/<USER>/vagrant-hadoop-hive-spark

2. If there are other vagrant VMs set up according to the same instructions on the same machine, then need to change the forwarded ports (the 2nd column of ports) in the file "Vagrantfile". In the example below, excerpted from my Vagrantfile, I've incremented the forwarded ports by 1:

    config.vm.network "forwarded_port", guest: 8080, host: 8081
    config.vm.network "forwarded_port", guest: 8088, host: 8089
    config.vm.network "forwarded_port", guest: 9083, host: 9084
    config.vm.network "forwarded_port", guest: 4040, host: 4041
    config.vm.network "forwarded_port", guest: 18888, host: 18889
    config.vm.network "forwarded_port", guest: 16010, host: 16011

Remember to visit the adjusted ports on the running VM.

3. The most useful vagrant commands:
vagrant up      # start up the vagrant VM if not already running.
            # May need to provide VM's ID if there's more than one vagrant VM
ssh vagrant     # ssh into the sole vagrant VM, else may need to provide vagrant VM's ID

vagrant halt    # to shutdown the vagrant VM. Provide VM's ID if there's more than one vagrant VM.

(vagrant destroy)   # to get rid of your vagrant VM. Useful if you've edited your Vagrantfile


4. Inside the VM, /home/<USER>/vagrant-hadoop-hive-spark will be shared and mounted as /vagrant
Remember, this is the folder containing Vagrantfile. It's easy to use the shared folder to transfer files between the VM and the actual machine that hosts it.

5. Install EMACS, FIREFOX AND MAVEN on the vagrant VM:
Start up vagrant machine ("vagrant up") and ssh into it ("ssh vagrant") if you haven't already.


a. sudo apt-get -y install firefox

b. sudo apt-get install emacs

c. sudo apt-get install maven
  (or sudo apt update
   sudo apt install maven)

Maven is needed for the commoncrawl github projects we'll be working with.


6. Although you can edit the Vagrantfile to have emacs and maven automatically installed when the vagrant VM is created, for firefox, you're advised to install it as above.

To be able to view firefox from the machine hosting the VM, use a separate terminal and run:
   vagrant ssh -- -Y
[or "vagrant ssh -- -Y node1", if VM ID is node1]

READING ON Vagrant:
    * Guide: https://www.vagrantup.com/intro/getting-started/index.html
    * Common cmds: https://blog.ipswitch.com/5-vagrant-commands-you-need-to-know
    * vagrant reload = vagrant halt + vagrant up https://www.vagrantup.com/docs/cli/reload.html
    * https://stackoverflow.com/questions/46903623/how-to-use-firefox-ui-in-vagrant-box
    * https://stackoverflow.com/questions/22651399/how-to-install-firefox-in-precise64-vagrant-box
      sudo apt-get -y install firefox
    * vagrant install emacs: https://medium.com/@AnnaJS15/getting-started-with-virtualbox-and-vagrant-8d98aa271d2a

    * hadoop conf: sudo vi /usr/local/hadoop-2.7.6/etc/hadoop/mapred-site.xml
    * https://data-flair.training/forums/topic/mkdir-cannot-create-directory-data-name-node-is-in-safe-mode/

-------------------------------------------------
B. Create IAM role on Amazon AWS to use S3 (S3a)
-------------------------------------------------
CommonCrawl (CC) crawl data is stored on Amazon S3, specifically the newest version Amazon s3a which has superceded both s3 and its earlier successor s3n.

In order to have access to cc crawl data, need to create an IAM role on Dr Bainbridge's Amazon AWS account and configure its profile for commoncrawl.

1. Log into Dr Bainbridge's Amazon AWS account
- In the aws management console:
[email protected]
lab pwd, capital R and ! (maybe g)


2. Create a new "iam" role or user for "commoncrawl(er)" profile

3. You can create the commoncrawl profile while creating the user/role, by following the instructions at https://answers.dataiku.com/1734/common-crawl-s3
which states

"Even though the bucket is public, if your AWS key does not have your full permissions (ie if it's a restricted IAM user), you need to grant explicit access to the commoncrawl bucket: attach the following policy to your IAM user"

#### START POLICY IN JSON FORMAT ###
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "Stmt1503647467000",
            "Effect": "Allow",
            "Action": [
                "s3:GetObject",
                "s3:ListBucket"
            ],
            "Resource": [
                "arn:aws:s3:::commoncrawl/*",
                "arn:aws:s3:::commoncrawl"
            ]
        }
    ]
}
#### END POLICY ###


--------------------------------------------------------------------------
C. Configure Spark on your vagrant VM with the AWS authentication details
--------------------------------------------------------------------------
Any Spark jobs run against the CommonCrawl data stored on Amazon s3a need to be able to authenticate with the AWS IAM role you created above. In order to do this, you'll want to put the Amazon AWS access key and secret key in the SPARK configuration properties file. (Instead of configuring these values in hadoop's core-site.xml, as in the latter case, the authentication details don't get copied across when distributed jobs are run to other computers in the distributed cluster that also need to know how to authenticate):

1. Inside the vagrant vm:

   sudo emacs /usr/local/spark-2.3.0-bin-hadoop2.7/conf/spark-defaults.conf
   (sudo emacs $SPARK_HOME/conf/spark-defaults.conf)

2. Edit the spark properties conf file to contain these 3 new properties:

    spark.hadoop.fs.s3a.impl=org.apache.hadoop.fs.s3a.S3AFileSystem  
    spark.hadoop.fs.s3a.access.key=PASTE_IAM-ROLE_ACCESSKEY_HERE
    spark.hadoop.fs.s3a.secret.key=PASTE_IAM-ROLE_SECRETKEY_HERE

Instructions on which properties to set were taken from:
- https://stackoverflow.com/questions/30385981/how-to-access-s3a-files-from-apache-spark
- https://community.cloudera.com/t5/Community-Articles/HDP-2-4-0-and-Spark-1-6-0-connecting-to-AWS-S3-buckets/ta-p/245760

[NOTE, inactive alternative: Instead of editing spark's config file to set these properties, these properties can also be set in the bash script that executes the commoncrawl Spark jobs:

$SPARK_HOME/bin/spark-submit \
   ...
   --conf spark.hadoop.fs.s3a.access.key=ACCESSKEY \
   --conf spark.hadoop.fs.s3a.secret.key=SECRETKEY \
   --conf spark.hadoop.fs.s3a.impl=org.apache.hadoop.fs.s3a.S3AFileSystem \
   ...

But better not to hardcode authentication details into code, so I did it the first way.
]

----------------------------------------------------------------------
NOTE:
Script scripts/setup.sh now is automated to do the steps in D-F below
and prints out the main instruction for G.


----------------------------------------------------------------------
D. OPTIONAL? Further configuration for Hadoop to work with Amazon AWS
----------------------------------------------------------------------
The following 2 pages state that additional steps are necessary to get hadoop and spark to work with AWS S3a:

- https://stackoverflow.com/questions/30385981/how-to-access-s3a-files-from-apache-spark
- https://community.cloudera.com/t5/Community-Articles/HDP-2-4-0-and-Spark-1-6-0-connecting-to-AWS-S3-buckets/ta-p/245760

I'm not sure whether these steps were really necessary in my case, and if so, whether it was A or B below that got things working for me. However, I have both A and B below set up.


A. Check your maven installation for necessary jars:

1. Installing maven may already have got the specifically recommended version of AWS-Java-SDK (aws-java-sdk-1.7.4.jar) and v2.7.6 hadoop-aws matching the vagrant VM's hadoop version (hadoop-aws-2.7.6.jar). Check these locations, as that's where I have them:
- /home/vagrant/.m2/repository/com/amazonaws/aws-java-sdk/1.7.4/aws-java-sdk-1.7.4.jar
- /home/vagrant/.m2/repository/org/apache/hadoop/hadoop-aws/2.7.6/hadoop-aws-2.7.6.jar

The specifically recommended v.1.7.4 from the instructions can be found off https://mvnrepository.com/artifact/com.amazonaws/aws-java-sdk/1.7.4 at https://repo1.maven.org/maven2/com/amazonaws/aws-java-sdk/1.7.4/aws-java-sdk-1.7.4.jar

2. The script that runs the 2 Spark jobs uses the above paths for one of the spark jobs:
   $SPARK_HOME/bin/spark-submit \
       --jars file:/home/vagrant/.m2/repository/com/amazonaws/aws-java-sdk/1.7.4/aws-java-sdk-1.7.4.jar,file:/home/vagrant/.m2/repository/org/apache/hadoop/hadoop-aws/2.7.6/hadoop-aws-2.7.6.jar \
       --driver-class-path=/home/vagrant/.m2/repository/com/amazonaws/aws-java-sdk/1.7.4/aws-java-sdk-1.7.4.jar:/home/vagrant/.m2/repository/org/apache/hadoop/hadoop-aws/2.7.6/hadoop-aws-2.7.6.jar \

However the other Spark job in the script does not set --jars or --driver-class-path, despite also referring to the s3a://commoncrawl table. So I'm not sure whether the jars are necessary or whether theywere just being ignored when provided.

B. Download jar files and put them on the hadoop classpath:

1. download the jar files:
- I obtained aws-java-sdk-1.11.616.jar (v1.11) from https://aws.amazon.com/sdk-for-java/

- I downloaded hadoop-aws 2.7.6 jar, as it goes with my version of hadoop, from https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-aws/2.7.6

2. The easiest solution is to copy the 2 downloaded jars onto a location in the hadoop classpath.

a. The command that shows the paths present on the Hadoop CLASSPATH:
    hadoop classpath
One of the paths this will list is /usr/local/hadoop-2.7.6/share/hadoop/common/

b. SUDO COPY the 2 downloaded jar files, hadoop-aws-2.7.6.jar and aws-java-sdk-1.11.616.jar, to this location:

     sudo cp hadoop-aws-2.7.6.jar /usr/local/hadoop-2.7.6/share/hadoop/common/.
     sudo cp aws-java-sdk-1.11.616.jar /usr/local/hadoop-2.7.6/share/hadoop/common/.

Any hadoop jobs run will now find these 2 jar files on the classpath.

[NOTE, unused alternative: Instead of copying the 2 jar files into a system location, assuming they were downloaded into /home/vagrant/lib, you can also export a custom folder's jar files into the hadoop classpath from the bash script that runs the spark jobs. This had no effect for me, and was commented out, and is another reason why I'm not sure if the 2 jar files were even necessary.
#export LIBJARS=/home/vagrant/lib/*                                 
#export HADOOP_CLASSPATH=`echo ${LIBJARS} | sed s/,/:/g`
]


------------------------------------
E. Setup cc-index-table git project
------------------------------------
Need to be inside the vagrant VM.

1. Since you should have already installed maven, you can checkout and compile the cc-index-table git project.

       git clone https://github.com/commoncrawl/cc-index-table.git

2. Modify the toplevel pom.xml file used by maven by changing the spark version used to 2.3.0 and adding a dependency for hadoop-aws 2.7.6, as indicated below:

17c17,18
<       <spark.version>2.4.1</spark.version>
---
>       <!--<spark.version>2.4.1</spark.version>-->
>       <spark.version>2.3.0</spark.version>
135a137,143
>       <dependency>
>         <groupId>org.apache.hadoop</groupId>
>         <artifactId>hadoop-aws</artifactId>
>         <version>2.7.6</version>
>       </dependency>
> 

3. Although cc-index-table will compile successfully after the above modifications, it will nevertheless throw an exception when it's eventually run. To fix that, edit the file "cc-index-table/src/main/java/org/commoncrawl/spark/examples/CCIndexWarcExport.java" as follows:

a. Set option(header) to false, since the csv file contains no header row, only data rows.
   Change:
    sqlDF = sparkSession.read().format("csv").option("header", true).option("inferSchema", true)
                                        .load(csvQueryResult);
   To
    sqlDF = sparkSession.read().format("csv").option("header", false).option("inferSchema", true)
                                        .load(csvQueryResult);

b. The 4 column names are inferred as _c0 to _c3, not as url/warc_filename etc.
   Comment out:
    //JavaRDD<Row> rdd = sqlDF.select("url", "warc_filename", "warc_record_offset", "warc_record_length").rdd()
                                .toJavaRDD();
   Replace with the default inferred column names:
    JavaRDD<Row> rdd = sqlDF.select("_c0", "_c1", "_c2", "_c3").rdd()
                                .toJavaRDD();

// TODO: link svn committed versions of orig and modified CCIndexWarcExport.java here.

4. Now (re)compile cc-index-table with the above modifications:

   cd cc-index-table
   mvn package

-------------------------------
F. Setup warc-to-wet tools
-------------------------------
To convert WARC files to WET (.warc.wet) files, need to checkout, set up and compile a couple more tools. These instructions are derived from those at https://groups.google.com/forum/#!topic/common-crawl/hsb90GHq6to

1. Grab and compile the 2 git projects for converting warc to wet:
     git clone https://github.com/commoncrawl/ia-web-commons
     cd ia-web-commons
     mvn install

     git clone https://github.com/commoncrawl/ia-hadoop-tools
     cd ia-hadoop-tools
     # can't compile this yet
     

2. Add the following into ia-hadoop-tools/pom.xml, in the top of the <dependencies> element, so that maven finds an appropriate version of the org.json package and its JSONTokener (version number found off https://mvnrepository.com/artifact/org.json/json):

   <dependency>
      <groupId>org.json</groupId>
      <artifactId>json</artifactId>
      <version>20131018</version>
    </dependency>

[
  UNFAMILAR CHANGES that I don't recollect making and that may have been a consequence of the change in step 1 above:
  a. These further differences show up between the original version of the file in pom.xml.orig and the modified new pom.xml:
  ia-hadoop-tools>diff pom.xml.orig pom.xml

  <       <groupId>org.netpreserve.commons</groupId>
  <       <artifactId>webarchive-commons</artifactId>
  <       <version>1.1.1-SNAPSHOT</version>
  ---
  >       <groupId>org.commoncrawl</groupId>
  >       <artifactId>ia-web-commons</artifactId>
  >       <version>1.1.9-SNAPSHOT</version>

  b. I don't recollect changing or manually introducing any java files. I just followed the instructions at https://groups.google.com/forum/#!topic/common-crawl/hsb90GHq6to

  However, a diff -rq between the latest "ia-hadoop-tools" gitproject checked out a month after the "ia-hadoop-tools.orig" checkout I ran, shows the following differences in files which are not shown as recently modified in github itself in that same period.

  ia-hadoop-tools> diff -rq ia-hadoop-tools ia-hadoop-tools.orig/
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/io/HDFSTouch.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/io/HDFSTouch.java differ
  Only in ia-hadoop-tools/src/main/java/org/archive/hadoop/jobs: ArchiveFileExtractor.java
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/jobs/CDXGenerator.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/jobs/CDXGenerator.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/jobs/JobDriver.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/jobs/JobDriver.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/jobs/WARCMetadataRecordGenerator.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/jobs/WARCMetadataRecordGenerator.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/jobs/WATGenerator.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/jobs/WATGenerator.java differ
  Only in ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/jobs: WEATGenerator.java
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/mapreduce/ZipNumPartitioner.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/mapreduce/ZipNumPartitioner.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/pig/ZipNumRecordReader.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/pig/ZipNumRecordReader.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/hadoop/streaming/ZipNumRecordReader.java and ia-hadoop-tools.orig/src/main/java/org/archive/hadoop/streaming/ZipNumRecordReader.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/server/FileBackedInputStream.java and ia-hadoop-tools.orig/src/main/java/org/archive/server/FileBackedInputStream.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/server/GZRangeClient.java and ia-hadoop-tools.orig/src/main/java/org/archive/server/GZRangeClient.java differ
  Files ia-hadoop-tools/src/main/java/org/archive/server/GZRangeServer.java and ia-hadoop-tools.orig/src/main/java/org/archive/server/GZRangeServer.java differ
]

3. Now can compile ia-hadoop-tools:
   cd ia-hadoop-tools
   mvn package

4. Can't run it until guava.jar is on hadoop classpath. Locate a guava.jar and put it into an existing location checked for by hadoop classpath:

   locate guava.jar
       # found in /usr/share/java/guava.jar and /usr/share/maven/lib/guava.jar
   diff /usr/share/java/guava.jar /usr/share/maven/lib/guava.jar   
    # identical/no difference, so can use either
   sudo cp /usr/share/java/guava.jar /usr/local/hadoop/share/hadoop/common/.
    # now guava.jar has been copied into a location on hadoop classpath


Having done the above, our bash script will now be able to convert WARC to WET files when it runs:
    $HADOOP_MAPRED_HOME/bin/hadoop jar $PWD/target/ia-hadoop-tools-jar-with-dependencies.jar WEATGenerator -strictMode -skipExisting batch-id-xyz hdfs:///user/vagrant/PATH/TO/warc/*.warc.gz
Our script expects a specific folder structure: there should be a "warc" folder (containing the warc files), which is supplied as above, but also an empty "wet" and "wat" folder at the same level as the "warc" folder.


When the job is running, can visit the Spark Context at http://node1:4040/jobs/ (http://node1:4041/jobs/ for me first time, since I forwarded the vagrant VM's ports at +1. However, subsequent times it was on node1:4040/jobs?)

-----------------------------------
G. Getting and running our scripts
-----------------------------------

1. Grab our 1st bash script and put it into the /home/vagrant/cc-index-table/src/script:
       cd cc-index-table/src/script
       wget http://svn.greenstone.org/gs3-extensions/maori-lang-detection/hdfs-cc-work/scripts/get_maori_WET_records_for_crawl.sh
       chmod u+x get_maori_WET_records_for_crawl.sh

RUN AS:
cd cc-index-table
./src/script/get_maori_WET_records_for_crawl.sh <crawl-timestamp>
                where crawl-timestamp of form "CC-MAIN-YYYY-##" >= September 2019

OUTPUT:
After hours of processing (leave it to run overnight), you should end up with:
      hdfs dfs -ls /user/vagrant/<crawl-timestamp>
In particular, the zipped wet records at hdfs:///user/vagrant/<crawl-timestamp>/wet/
that we want would have been copied into /vagrant/<crawl-timestamp>-wet-files/


The script get_maori_WET_records_for_crawl.sh
- takes a crawl timestamp of the form "CC-MAIN-YYYY-##" from Sep 2018 onwards (before which content_languages were not indexed). The legitimate crawl timestampts are listed in the first column at http://index.commoncrawl.org/
- runs a spark job against CC's AWS bucket over s3a to create a csv table of MRI language records
- runs a spark job to download all the WARC records from CC's AWS that are denoted by the csv file's records into zipped warc files
- converts WARC to WET: locally converts the downloaded warc.gz files into warc.wet.gz (and warc.wat.gz) files


2. Grab our 2nd bash script and put it into the top level of cc-index-table (/home/vagrant/cc-index/table):

       cd cc-index-table
       wget http://svn.greenstone.org/gs3-extensions/maori-lang-detection/hdfs-cc-work/scripts/get_Maori_WET_records_from_CCSep2018_on.sh
       chmod u+x get_Maori_WET_records_from_CCSep2018_on.sh

RUN FROM cc-index-table DIRECTORY AS:
    (cd cc-index-table)
    ./get_Maori_WET_records_from_CCSep2018_on.sh

This script just runs the 1st script cc-index-table/src/script/get_maori_WET_records_for_crawl.sh (above) to process all listed common-crawls since September 2018.
If any fails, then the script will terminate. Else it runs against each common-crawl in sequence.

NOTE: If needed, update the script with more recent crawl timestamps from http://index.commoncrawl.org/

OUTPUT:
After days of running, will end up with:
      hdfs:///user/vagrant/<crawl-timestamp>/wet/
for each crawl-timestamp listed in the script,
which at present would have got copied into
      /vagrant/<crawl-timestamp>-wet-files/

Each of these output wet folders can then be processed in turn by CCWETProcessor.java from http://trac.greenstone.org/browser/gs3-extensions/maori-lang-detection/src/org/greenstone/atea/CCWETProcessor.java

-----------------------------------
H. Austici crawl
-----------------------------------
Austici's crawl: CLI to download web sites as WARCs, features basics to avoid crawler taps.

Out of several software to do site mirroring, Autistici's "crawl" seemed promising:
https://anarc.at/services/archive/web/

- CLI.
- Can download a website quite simply, though flags for additional settings are available.
- Coded to prevent common traps.
- Downloads website as WARC file
- Now I have the WARC to WET process working for the WARC file it produced for the usual test site (Dr Bainbridge's home page)

Need to have Go installed in order to install and run Autistici's crawl.
Not a problem, because I can do it on the remote machine (which also hosts the hdfs) where I have sudo powers.

INSTRUCTIONS

1. Install go 1.11 by following instructions at https://medium.com/better-programming/install-go-1-11-on-ubuntu-18-04-16-04-lts-8c098c503c5f
2. Create go environment:
#!/bin/bash
# environment vars for golang               
export GOROOT=/usr/local/go
export GOPATH=$HOME/go
export PATH=$GOPATH/bin:$GOROOT/bin:$PATH
3. The https://git.autistici.org/ale/crawl/README.md instructions on installing are not very clear and don't work as is at this stage.

These steps work:

cd $GOPATH
mkdir bin
mkdir src
cd src

4. Since trying to go install the crawl url didn't work
https://stackoverflow.com/questions/14416275/error-cant-load-package-package-my-prog-found-packages-my-prog-and-main
[https://stackoverflow.com/questions/26694271/go-install-doesnt-create-any-bin-file]

vagrant@node2:~/go/src$
  mkdir -p git.autistici.org/ale
  cd git.autistici.org/ale
  git clone https://git.autistici.org/ale/crawl.git

[Now can run the install command in README.md:]
  cd $GOPATH/src
  go install git.autistici.org/ale/crawl/cmd/crawl

Now we should have a $GOPATH/bin folder containing the "crawl" binary

5. Run a crawl:
  cd $GOPATH/bin
  ./crawl https://www.cs.waikato.ac.nz/~davidb/

which downloads the site and puts the warc file into the $GOPATH/bin folder.

More options, including output folder, WARC filename pattern for huge sites so that multiple warc files created for one site follow the same pattern are all in the instructions in README.md

6. To view the RAW contents of a WARC file:
https://github.com/ArchiveTeam/grab-site/blob/master/README.md#viewing-the-content-in-your-warc-archives

zless <warc-file-name>

zless already installed on vagrant file


-----------------------------------------------------------------------------------------------
How to run warc-to-wet conversion on sites downloaded as WARCs by Austici's "crawl" 
-----------------------------------------------------------------------------------------------
ISSUES CONVERTING WARC to WET:
---
WARC files produced by Autistici crawl are of a somewhat different format to CommonCrawl WARCs.
- missing elements in header
- different header elements
- ordering different (if that matters)

But WET is an official format, not CommonCrawl specific, as indicated by

https://library.stanford.edu/projects/web-archiving/research-resources/data-formats-and-apis
"WET (parsed text)

WARC Encapsulated Text (WET) or parsed text consists of the extracted plaintext, delimited by archived document. Each record retains the associated URL and timestamp. Common Crawl provides details on the format and Internet Archive provides documentation on usage, though they use different names for the format."

So must be possible to get WARC to WET conversion used for CommonCrawl data to work on Autistici crawl's WARC files.


RESOLUTION:
---
I made changes to 2 java source files in the 2 github projects ia-web-commons and ia-hadoop-tools, which we use for the WARC to WET processing of CommonCrawl data. These gitprojects (with modifications for commoncrawl) are already on http://trac.greenstone.org/browser/gs3-extensions/maori-lang-detection/hdfs-cc-work/gitprojects.

The changed files are as follows:
1. patches/WATExtractorOutput.java
   put into ia-web-commons/src/main/java/org/archive/extract
   after renaming existing to .orig

THEN RECOMPILE ia-web-commons with:
   mvn install

2. patches/GZRangeClient.java
   put into ia-hadoop-tools/src/main/java/org/archive/server
   after renaming existing to .orig
  
THEN RECOMPILE ia-hadoop-tools with:
   mvn package

Make sure to first compile ia-web-commons, then ia-hadoop-tools.


The modifications made to the above 2 files are as follows:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
1. ia-web-commons/src/main/java/org/archive/extract/WATExtractorOutput.java

[diff src/main/java/org/archive/extract/WATExtractorOutput.orig src/main/java/org/archive/extract/WATExtractorOutput.java]

162,163c162,163
<           targetURI = extractOrIO(md, "Envelope.WARC-Header-Metadata.WARC-Filename");
<       } else {
---
>           targetURI = extractOrIO(md, "Envelope.WARC-Header-Metadata.WARC-Warcinfo-ID");
>       } else {


2. ia-hadoop-tools/src/main/java/org/archive/server/GZRangeClient.java

[diff src/main/java/org/archive/server/GZRangeClient.orig src/main/java/org/archive/server/GZRangeClient.java]

76,83c76,82
<       "WARC/1.0\r\n" +
<       "WARC-Type: warcinfo\r\n" +
<       "WARC-Date: %s\r\n" +
<       "WARC-Filename: %s\r\n" +
<       "WARC-Record-ID: <urn:uuid:%s>\r\n" +
<       "Content-Type: application/warc-fields\r\n" +
<       "Content-Length: %d\r\n\r\n";
< 
---
>       "WARC/1.0\r\n" +
>       "Content-Type: application/warc-fields\r\n" +
>       "WARC-Type: warcinfo\r\n" +
>       "WARC-Warcinfo-ID: <urn:uuid:%s>\r\n" +
>       "Content-Length: %d\r\n\r\n" +
>       "WARC-Record-ID: <urn:uuid:%s>\r\n" +       
>       "WARC-Date: %s\r\n";
115,119c114,119
<   private static String DEFAULT_WARC_PATTERN = "software: %s Extractor\r\n" +
<   "format: WARC File Format 1.0\r\n" +
<   "conformsTo: http://bibnum.bnf.fr/WARC/WARC_ISO_28500_version1_latestdraft.pdf\r\n" +
<   "publisher: Internet Archive\r\n" +
<   "created: %s\r\n\r\n";
---
>   private static String DEFAULT_WARC_PATTERN = "Software: crawl/1.0\r\n" +
>   "Format: WARC File Format 1.0\r\n" +
>       "Conformsto: http://bibnum.bnf.fr/WARC/WARC_ISO_28500_version1_latestdraft.pdf\r\n\r\n";
>     // +
>     //"publisher: Internet Archive\r\n" +
>     //"created: %s\r\n\r\n";
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<


3. To run WARC to WET, the warc needs to live on hdfs in a warc folder and there should be wet and wat folders at the same level.

For example, assume that running Autistici's crawl generated $GOPATH/bin/crawl.warc.gz
(default location and filename unless you pass flags to crawl CLI to control these)

a. Ensure you get crawl.warc.gz onto the vagrant VM that has the git projects for WARC-to-WET installed, recompiled with the above modifications.

b. Now, create the folder structure needed for warc-to-wet conversion:
   hdfs dfs -mkdir /user/vagrant/warctest
   hdfs dfs -mkdir /user/vagrant/warctest/warc
   hdfs dfs -mkdir /user/vagrant/warctest/wet
   hdfs dfs -mkdir /user/vagrant/warctest/wat

c. Put crawl.warc.gz into the warc folder on hfds:
   hdfs dfs -put crawl.warc.gz /user/vagrant/warctest/warc/.

d. Finally, time to run the actual warc-to-wet conversion from ia-hadoop-tools:
   cd ia-hadoop-tools
   WARC_FOLDER=/user/vagrant/warctest/warc
   $HADOOP_MAPRED_HOME/bin/hadoop jar $PWD/target/ia-hadoop-tools-jar-with-dependencies.jar WEATGenerator -strictMode -skipExisting batch-id-xyz $WARC_FOLDER/crawl*.warc.gz

More meaningful when the WARC_FOLDER contains multiple *.warc.gz files,
as the above will use map-reduce to generate a *.warc.wet.gz file in the output wet folder for each input *.warc.gz file.

e. Copy the generated wet files across from /user/vagrant/warctest/wet/:

   (cd /vagrant or else
   cd /home/vagrant
   )
   hdfs dfs -get /user/vagrant/warctest/wet/crawl.warc.wet.gz .

or, when dealing with multiple input warc files, we'll have multiple wet files:
    hdfs dfs -get /user/vagrant/warctest/wet/*.warc.wet.gz


f. Now can view the contents of the WET files to confirm they are what we want:
   gunzip crawl.warc.wet.gz
   zless crawl.warc.wet

The wet file contents should look good now: the web pages as WET records without html tags.


----------------------------------------------------
I. Setting up Nutch v2 on its own Vagrant VM machine
----------------------------------------------------
1. Untar vagrant-for-nutch2.tar.gz
2. Follow the instructions in vagrant-for-nutch2/GS_README.txt

---
REASONING FOR THE NUTCH v2 SPECIFIC VAGRANT VM:
---
We were able to get nutch v1 working on a regular machine.

From a few pages online starting with https://stackoverflow.com/questions/33354460/nutch-clone-website, it appeared that "./bin/nutch fetch -all" was the nutch command to mirror a web site. Nutch v2 introduced the -all flag to the ./bin/nutch fetch command. And nutch v2 required HBase which presupposes hadoop.

Our vagrant VM for commoncrawl had an incompatible version of HBase but this version was needed for that VM's version of hadoop and spark. So Dr Bainbridge came up with the idea of having a separate Vagrant VM for Nutch v2 which would have the version of HBase it needed and a Hadoop version matching that. Compatible versions with nutch 2.3.1 are mentioned at https://waue0920.wordpress.com/2016/08/25/nutch-2-3-1-hbase-0-98-hadoop-2-5-solr-4-10-3/
(Another option was MongoDB instead of HBase, https://lobster1234.github.io/2017/08/14/search-with-nutch-mongodb-solr/, but that was not even covered in the apache nutch 2 installation guide.)



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