Startup of embedded web container

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Denodo includes an Apache Tomcat Web Container as part of the distribution to support all HTTP(s) accessible components.  This includes:

• Web Design Studio (8.0+)
• Data Catalog (Information Self Service Tool prior to 7.0)
• Diagnostic & Monitoring Tool
• Scheduler Administration Tool
• Solution Manager Administration Tool (7.0+)
• Denodo Restful-WS service
• Denodo OData4 Service (7.0+)
• Denodo GraphQL Service (8.0+)
• Denodo SSO mechanism (8.0+)
• Denodo export mechanism (prior to 8.0)
• Any SOAP or REST Web Services published as part of the metadata model

Web Services generated as part of the metadata model can be exported as war archives to deploy to external J2EE Application Servers, but it is generally recommended to deploy them to the embedded container to avoid introducing unnecessary network latency.  It is strongly recommended that all other modules run only within the Tomcat web container.

When any Denodo web application is started via the standard scripts, Denodo checks if the Tomcat server is running, and starts it if it is not.  The applications started automatically with the VDP server can be controlled by editing the  <DENODO_HOME>/conf/vdp/VDBConfiguration.properties or <SOLUTION_MANAGER_HOME>/conf/vdp/VDBConfiguration.properties file while the VDP Server is stopped. The com.denodo.tomcat.webapps property controls which internal VDP web applications are started, and supports the following values as a comma separated list, depending on version:

• sso (8.0+)
• denodo-restfulws
• denodo-odata4-service (7.0+)
• denodo-graphql-service (8.0+)
• export (prior to 8.0)

The com.denodo.webcontainer.startonstartup property controls whether or not the Web Container is started with the VDP Server, and supports the possible values:

• on (default value): the embedded container will launch with VDP Server (and deploy the services identified by the webapps property)
• off: the embedded container will not be launched with VDP Server.

The status of the Web Container can be checked using the Virtual DataPort Administration Tool via “Tools” > “Web services container”.  This window displays the status with two possible values:

• ON: the Web Container is running.
• OFF: the Web Container is not running.

When the Web Container is running, published web services can be Deployed, Undeployed, and Redeployed via this interface or VQL Statement.  

The Web Container can also be monitored, stopped, and started via VQL Statement:

• webcontainer status
• webcontainer stop
• webcontainer start

Important Notes:

• The applications listed in the com.denodo.tomcat.webapps property will only deploy with the VDP server controls.  If com.denodo.webcontainer.startonstartup is set to off and the Tomcat server is started via Data Catalog or another tool, the internal VDP web applications will not be started.  To control the start of these web applications independently of the VDP server start, use the VQL webcontainer start command to start Tomcat prior to starting any external web applications.
• Contrariwise, the Web Container can not be stopped via the VQL webcontainer stop if external web applications such as Data Catalog or Scheduler Administration Tool are running.  These applications would need to be undeployed/stopped first.
• The applications listed in the com.denodo.tomcat.webapps property can not be started or stopped independently.  They must be configured as a set to be deployed whenever Tomcat is started via VDP.
• When the Web Container starts via VDP Server, any SOAP or REST web service elements will deploy based on which were deployed when the VDP Server was last shut down.  To control which services deploy automatically on the next start up, execute a series of VQL commands to undeploy before shutting down the server.

• undeploy webservice example1;
• undeploy webservice example2;
• etc...