stormcrawler-docker

Resources for running StormCrawler in Docker containers.

The docker compose file runs URFrontier; if you want to use a different backend (e.g. Elasticsearch / OpenSearch) instead, add the required sections in the docker-compose.yml file accordingly.

This project does not cover the basics of StormCrawler. If you need to understand how StormCrawler works, please refer to the documentation there.

Prerequisites

• Docker
• Docker-compose
• (optional) Apache Maven

First, you will need to build a custom Docker image to extend the one for Apache Storm with docker build -t digitalpebble/storm_maven:2.6 .. This will make it easier for you to launch the crawler using the containers.

Create a directory 'frontier' in the current directory with mkdir -m 777 frontier.

Instructions

We will assume that you have a StormCrawler project available, if you do, you can copy its content to a crawldata directory within the current one or modify the volume in the runner definition in the docker-compose file

    volumes:
      - "./myexistingsetup:/crawldata"

If you don't, you can generate one using the Maven archetype

mvn archetype:generate -DarchetypeGroupId=com.digitalpebble.stormcrawler -DarchetypeArtifactId=storm-crawler-archetype -DarchetypeVersion=2.9 -DartifactId=crawldata -DgroupId=com.digitalpebble -Dversion=1.0

The command above will generate a StormCrawler setup in the directory 'crawldata'. Look at the README file generated and compile with mvn clean package.

Finally, start the services with docker-compose up -d.

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*** IF YOU ARE DON'T HAVE A STORMCRAWLER SETUP AND NEITHER MAVEN NOR JAVA'***

IMPORTANT Make sure you give +rw access to any user on the crawldata directory, this is done with chmod -R a+rw crawldata; otherwise the container won't be able to create any content in it.

Start the runner container

docker-compose run runner bash

this is used to build a topology with Maven but also send it to the Storm cluster

Now that you are within the runner container, you can run the command above within the container.

alias mvn="mvn -Dmaven.repo.local=/crawldata/.repository"
cd /crawldata 
mvn archetype:generate -DarchetypeGroupId=com.digitalpebble.stormcrawler -DarchetypeArtifactId=storm-crawler-archetype -DarchetypeVersion=2.9 -DartifactId=crawler -DgroupId=com.digitalpebble -Dversion=1.0

then press Enter to confirm the parameters.

You can change the access rights for the crawler directory so that its content can be modified from outside the container.

chmod a+rw -R crawler

You should see a directory called crawler in the crawldata directory you created earlier on your machine. It contains the resources and code of the crawl topology.

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Now, whether the StormCrawler setup you will be using was preexisting, generated locally or within the runner container, you should have it in crawldata/crawler.

To run the topology, go back to the runner container (assuming you had left it) and call

docker-compose run runner bash
cd /crawldata/crawler
alias mvn="mvn -Dmaven.repo.local=/crawldata/.repository"

then follow the instructions in the README file, the first one being to compile the uber jar with mvn clean package. Bear in mind that you might need to change the configuration of the topology and use the container names from the compose file (e.g. frontier).

You can close the runner once the topology is launched in deployed mode. In local mode, you need to keep it open.