GATE

GATE is an e-assessment system specifically designed to support programming education.

This system is able to help with the process of exercise management and assessment for large programming classes at university level. The implemented system can be configured to allow for self-assessments of students and can check solutions submitted by studens for plagiarism.

How to setup GATE?

Please read the whole procedure in advance to executing it.

Installation steps of required software

• Install Java (17 is recommended, 21 also works)
  • On *nix (such as Debian) use the openjdk-17-jre-headless package
  • On Windows you can use Liberica OpenJDK 17
• Install Apache Tomcat 9 (e.g., on Debian-based systems use the tomcat9 package)
  • After installation Tomcat usually listens on locahost:8080
  • For development it is recommended to download the binary archive and integrate Tomcat into the used IDE, e.g. into Eclipse.
• Install MariaDB
  • For a development machine on Windows XAMPP is recommended which comes with phpMyAdmin a nice administration interface for MariaDB
• For development Eclipse (IDE for Enterprise Java Developers) >= 2022-09 is recommended
  • It may be necessary to build GATE once using the Maven compile goal to ensure that all required dependencies are available locally (in particular, hibernate-jpamodelgen).
• For production use, it is recommended to run Apache Tomcat behind Apache httpd, connecting Tomcat using mod_proxy_ajp, terminate SSL/TLS in httpd and probably use Shibboleth for Single-Sign on.
  • Configure the VHost with mod_proxy_ajp:

    ProxyPreserveHost On
    ProxyStatus On
    
    ProxyPass / ajp://localhost:8009/ secret=SECRET
    

    • Make sure Tomcat is not accessible directly (e.g., ports 8080, 8009, 8443); e.g. make port 8009 listen on ::1 only and comment all other Connectors in server.xml.
    • Clustering is possible (needs in Server/Engine[@jvmRoute] to be configured in server.xml as jvm1 or jvm2):

      <Proxy "balancer://mycluster">
          BalancerMember ajp://srv1:8009 secret=SECRET route=jvm1
          BalancerMember ajp://srv2:8009 secret=SECRET route=jvm2
          ProxySet lbmethod=byrequests stickysession=JSESSIONID
      </Proxy>
      ProxyPass "/" "balancer://mycluster/"
      

  • How to configure Shibboleth:
    • Install shibd and configure it (cf. https://www.switch.ch/aai/guides/sp/installation-2.5/), make sure the ApplicationDefault configuration in shibboleth2.xml contains attributePrefix="AJP_" (cf. https://wiki.shibboleth.net/confluence/display/SHIB2/NativeSPJavaInstall; please also make sure the AJP connector in Tomcat server.xml does not block the Shibboleth request attributes, e.g. by setting allowedRequestAttributesPattern=".*" or more restrictive "^(Shib-.*|givenName|eppn|sn|mail|persistent-id)$"), has a large enough proxys packet size (packetSize="65536"), and eppn is set for the REMOTE_USER in shibboleth2.xml (should match userAttribute, see below); also make sure /Shibboleth.sso/Logout can be used for logout (cf. src/main/java/de/tuclausthal/submissioninterface/servlets/controller/Logout.java)
    • Enable Shibboleth protection for the Overview servlet:

      ProxyPass /Shibboleth.sso/ !
      ProxyPass /Shibboleth/ !
      ProxyPass /shibboleth-sp/ !
      
      <Location /gate/servlets/Overview>
         AuthType shibboleth
         ShibRequireSession On
         require valid-user
      </Location>
      ProxyIOBufferSize 65536
      

    • For debugging: Please not that the Shibboleth attributes passed to Tomcat don't show up when iterating over the request variables. They need to be explicitly named (e.g., uid or Shib-Identity-Provider).
• For building the whole package you need maven (also often available as a package on *nix systems)
• For running the cron task regularly with the predefined script submissiondir/runtests.sh you need the lockfile tool (usually part of the procmail package on *nix systems)
• For using Docker-based tests you need to install Docker

Database

• Decide what user and password to use (for production use a dedicated user is recommended)
• Create a new database
• Import mysql.sql

Configuration files

• src/main/resources/hibernate.cfg.xml for the database configuration
  • Set the database name, username and password here
• src/main/webapp/WEB-INF/web.xml for Tomcat and GATE specific configurations
  • Adjust the datapath here, please make sure that this is accessible by Tomcat (should be read-only), use e.g. /srv/gate/ or c:\gate here. Create subdirectories named lectures and logs that are writable for the tomcat user where the user data and logs are stored.
    • On *nix the system Tomcat runs as the user tomcat, so make sure that the user has appropriate permissions, also on Debian-based systems, Tomcat might be sandboxed by systemd. Create a file /etc/systemd/system/tomcat9.service.d/gate.conf containing:

      [Service]
      ReadWritePaths=/srv/gate/lectures/
      

      (afterwards, issue systemctl daemon-reload and systemctl restart tomcat)
  • For development:
    • Adjust login to de.tuclausthal.submissioninterface.authfilter.authentication.login.impl.Form
    • Adjust verify to de.tuclausthal.submissioninterface.authfilter.authentication.verify.impl.FakeVerify to disable any authentication
  • For production use:
    • Check the other configuration options, especially the mail related ones
    • For LDAP authentication set login to de.tuclausthal.submissioninterface.authfilter.authentication.login.impl.Form and verify to de.tuclausthal.submissioninterface.authfilter.authentication.verify.impl.LDAPVerify, configure LDAP related settings for the AuthenticationFilter (PROVIDER_URL, SECURITY_AUTHENTICATION, SECURITY_PRINCIPAL, matrikelNumberAttribute (optional), and userAttribute), please also look at src/main/java/de/tuclausthal/submissioninterface/authfilter/authentication/verify/impl/LDAPVerify.java whether special adjustments are needed (e.g. first and last name generation)
    • For Shibboleth set login to de.tuclausthal.submissioninterface.authfilter.authentication.login.impl.Shibboleth and verify to de.tuclausthal.submissioninterface.authfilter.authentication.verify.impl.ShibbolethVerify, configure Shibboleth related settings for the AuthenticationFilter (userAttribute and (optional) matrikelNumberAttribute); required fields from the Identity-Provider are sn, givenName, mail, and the configured userAttribute (usually eppn).
• submissiondir/runtests.sh for adjusting the paths
• src/main/webapp/WEB-INF/studiengaenge.txt for updating the list of study programs that are used for auto completion for the users of GATE

Building GATE for deploying to Tomcat

• Clone the repository
• Adjust the config files
• Run mvn clean verify
• The built .war file can then be found in the target directory

Alternatively you can also use GitLab CI/CD functionality and download the built .war file.

Installation steps for GATE

• Prepare the datapath in which the submissions will be stored (see the "Configuration files" section above)
  • Copy submissiondir/* and SecurityManager/NoExitSecurityManager.jar to that folder
  • If you want to use the JPlag plagiarism system, compile JPlag 2.12 into a single .jar (using the maven goal assembly:assembly inside the jplag directory and copy the final .jar (from the target folder) as jplag.jar into the root of the datapath
  • No files directly inside the data directory should be writable by the tomcat user.
• On Windows: Make sure the JAVA_HOME environment variable is set and points to the JDK directory (e.g. C:\Program Files\BellSoft\LibericaJDK-17\)
• Prepare Tomcat
  • If you want to have the user names on the Tomcat access log, you can use %{username}r (as a replacement for %u) for configuring the AccessLogValve pattern, cf. https://tomcat.apache.org/tomcat-9.0-doc/config/valve.html#Access_Log_Valve
  • Rename the built .war file to e.g. gate, because the name is then used to build the URL under which GATE will be accessible using Tomcat
  • Copy the .war file to the webapps folder of Tomcat (usually in C:\Program Files\Apache Tomcat 9\webapps or /var/lib/tomcat9/webapps/)
  • New versions of GATE can be easily deployed by just overriding the .war file in the webapps folder
• Create first user with superuser permissions: Execute util.CreateFirstUser with parameters: loginname emailaddress firtsname lastname. Alternatively, you can also manually insert a new row into the users table.
• Set up the cron task that performs regular tasks such as automatically start the plagiarism check in background
  • You can use the shipped script submissiondir/runtests.sh which should be in datapath and configure /etc/crontab: */10 * * * * tomcat /srv/submissioninterface/runtests.sh
  • Please make sure that you receive mails for the tomcat user in order to get errors of the cron task runner
• Restart Tomcat
• For using Docker-based tests
  • Build the local safe-docker image, based on safe-docker/Dockerfile (e.g., docker build --tag safe-docker . in the safe-docker folder of this repository). So far, the image is only prepared for supporting Haskell, you might want to extend it according to your needs.
  • Copy safe-docker/safe-docker to /usr/local/bin/safe-docker and make sure it is owned by root:root and has the permissions 700, you might want to check the parameters passed to docker. Requires the packages libipc-run-perl and libdata-guid-perl packages on Debian-based systems.
  • On Debian-based systems you might need to lift some systemd restrictions by creating the file /etc/systemd/system/tomcat9.service.d/gate-safe-docker.conf containing:

    [Service]
    NoNewPrivileges=false
    PrivateTmp=no
    ReadWritePaths=/tmp/
    

  • Set up sudo by inserting tomcat ALL= NOPASSWD: /usr/local/bin/safe-docker in /etc/sudoers.d/gate-safe-docker

Now GATE can be access using e.g. http://localhost:8080/GATE/ depending on your concrete local setup. It is recommended to run the self-test to check whether everything looks ok: http://localhost:8080/GATE/servlets/SelfTest