Lesson: start jetty

This lesson is known to work with hydra-head version 6.0.0.
Please update this wiki to reflect any other versions that have been tested.

Goals

• Start and Stop Jetty (which contains Fedora and Solr)

Explanation

Fedora and Solr are both Java web applications that need to run in a servlet container like Tomcat or Jetty. We installed hydra-jetty in the Lesson: Install hydra-jetty. Now whenever you need Fedora and Solr running, just start or stop that copy of hydra-jetty.

Tip: Sometimes people are confused about whether they need to restart jetty when they restart their Rails application. In most cases it is fine to leave jetty running when you start, stop, and restart the Rails application. The only exception is when you make changes to Solr's configuration or Fedora's configuration -- these would be changes to files inside of your copy of hydra-jetty (ie. jetty/solr/config), not changes to files in your Rails application's Ruby code. In those cases, where you have made changes to Solr or Fedora's configuration, you need to restart Jetty in order for those changes to take effect. The most common change that requires restarting jetty is when you modify the solrconfig.xml or schema.xml in your solr config directory.

Steps

Step 1: Start Jetty

At the project root, type

$> rake jetty:start

You should see output like this:

Initializing jettywrapper
Starting jetty with these values: 
jetty_home: /Users/justin/hydra-demo/jetty
solr_home: /Users/justin/hydra-demo/jetty/solr
jetty_command: java -Djetty.port=8983 -Dsolr.solr.home=/Users/justin/hydra-demo/jetty/solr -Xmx256m -XX:MaxPermSize=128m -jar start.jar
Logging jettywrapper stdout to /Users/justin/hydra-demo/jetty/jettywrapper.log
Wrote pid file to /Users/justin/hydra-demo/tmp/pids/_Users_justin_hydra-demo_jetty.pid with value 8315
Waited 5 seconds for jetty to start, but it is not yet listening on port 8983. Continuing anyway.
jetty started at PID 8315

hydra-jetty has a fair amount of stuff in it, so it may take up to a minute to start. You can check to see if it's started by going to http://localhost:8983/solr

If Fedora, Solr, or jetty itself are not starting, you'll want to look at the jettywrapper log to diagnose.

*Windows Tip: This rake task is not currently working on Windows (see jettywrapper issue #13 for status). In the meantime, start jetty manually

cd jetty
java -Djetty.port=8983 -Dsolr.solr.home=/Users/justin/hydra-demo/jetty/solr -Xmx256m -XX:MaxPermSize=128m -jar start.jar

Step 2: Look at the jettywrapper log

The jetty:start rake task runs jetty as a background job, so jetty's logs won't appear in your terminal. Instead they're written to the file jetty/jettywrapper.log. If you look at the output from running the jetty:start task, you'll see that one line gives you the full path to the file, for example:

Logging jettywrapper stdout to /Users/justin/hydra-demo/jetty/jettywrapper.log

You can open this log file with any text editor or log reader.

$> vi jetty/jettywrapper.log

Step 3: Monitor the jettywrapper log

Tip: if jetty is taking a long time to start, you can watch its output using the tail command with the path to your jettywrapper.log. For example:

$> tail -f jetty/jettywrapper.log

As Jetty, Fedora, and Solr start you will see more info being written to the log file. When jetty is ready, it will write one final line to the log and then wait for requests to come in from a browser. The line will look like

2013-04-06 11:59:59.473:INFO::Started [email protected]:8983

At that point you will be able to open jetty at http://localhost:8983 or, as the line in the log implies, http://0.0.0.0:8983 ( note: The root page will give a 404 error, but should have three links to the applications running in Jetty: /solr, /fedora and /fedora-test)

Step 4: Stop Jetty

You might have guessed this one. In order to stop jetty, at the project root, type

$> rake jetty:stop

Step 5: Start Jetty again

Before proceeding to the next step, make sure jetty is running. If you're not sure whether it's running, go to http://localhost:8983. If jetty is running a page will load. If jetty is not running no page will load.

If it's not running, just use the jetty:start rake task again.

$> rake jetty:start

Next Step

Go on to Lesson: Start the Application & Search for Results or return to the Dive into Hydra page.