Seaside Servlet Bridge for Squeak

Run Seaside in a Servlet container using GraalSqueak.

Usage

Add the dependency to your project

<dependency>
  <groupId>com.github.marschall</groupId>
  <artifactId>seaside-servlet-squeak</artifactId>
  <version>0.2.0</version>
</dependency>

Add the servlet to your web.xml

<servlet>
  <servlet-name>SeasideGraalSqueakBridgeServlet</servlet-name>
  <servlet-class>com.github.marschall.seaside.servlet.squeak.SeasideGraalSqueakBridgeServlet</servlet-class>
  <init-param>
    <param-name>smalltalk.ImagePath</param-name>
    <param-value>/WEB-INF/squeak/graalsqueak-1.0.0-rc2-seaside.image</param-value>
  </init-param>
  <async-supported>false</async-supported>
</servlet>

<servlet-mapping>
  <servlet-name>SeasideGraalSqueakBridgeServlet</servlet-name>
  <url-pattern>/*</url-pattern>
</servlet-mapping>

• load GraalSqueak-Core
• load Seaside

Installer ensureRecentMetacello. 
Metacello new
 baseline:'Seaside3';
 repository: 'github://SeasideSt/Seaside:develop/repository';
 load

• load Servlet-Seaside from this repository
• stop WAWebServerAdaptor as it fails during startup on GraalSqueak

And run with GraalVM.

Make sure you explode WARs for Tomcat, this means having unpackWARs="unpackWARs" on the <Host> element of server.xml. See Tomcat Web Application Deployment.

Make sure you have GraalSqueak installed in GraalVM.

Have a look at marschall/seaside-servlet-squeak-demo for a complete demo project.

Requirements

• GraalVM 19.2.0.1
• GraalSqueak
• gu install -u https://github.com/hpi-swa/graalsqueak/releases/download/1.0.0-rc2/graalsqueak-component-1.0.0-rc2-for-GraalVM-19.2.0.1.jar
• Servlet 3.1, but Servlet 4.0 is recommended

Limitations

• Limitations inherited from GraalSqueak
  • As GraalSqueak is currently not thread safe we are limited to one concurrent request. This is especially damning in case of blocking IO like database access.
  • Stack traces currently are not very useful.
  • Continuations are not supported.
  • Initial performance before warm up is not good compared to OpenSmalltalk VM.
  • Startup is not good compared to OpenSmalltalk VM.
  • Memory consumption and allocation rate are higher compared to OpenSmalltalk VM
• Asynchronous web request processing is not supported.

JMX

Included is a small framework to register Squeak objects as MBeans. To create a custom one:

• sublcass WAMBean
• override #objectName, check out the ObjectName class comment for information about the syntax
• add methods with <attribute> and <operation> pragmas
• have a look at WAAdminMBean for an example

Tips & Tricks

Enable Graal compliation logging

export CATALINA_OPTS="-Dgraal.TraceTruffleCompilation=true"

To make WAUrlDecodingFunctionalTest pass use, this is not needed in general

export CATALINA_OPTS="-Dorg.apache.tomcat.util.buf.UDecoder.ALLOW_ENCODED_SLASH=true"

If you have the Tomcat examples application installed (per default) this overrides the Seaside examples.

Warm up the compiler

for run in {1..100}; do curl -L 'http://127.0.0.1:8080/tests/functional/WALotsaLinksFunctionalTest?_s=_eYKKM3Gl3XzVM5T&_k=JIp_6FO_QQ26nQob' > /dev/null; done

Include the session key to avoid session creation and follow redirects.

Running the image directly with GraalVM

$JAVA_HOME/bin/graalsqueak --jvm --polyglot src/main/webapp/WEB-INF/squeak/graalsqueak-1.0.0-rc2-seaside.image

Building a native Tomcat image https://ci.apache.org/projects/tomcat/tomcat9/docs/graal.html