Chapter 20. Realtime Decision Server Functionality

20.1. Introduction

The Realtime Decision Server is a modular, standalone server component that can be used to instantiate and execute rules and processes. It exposes this functionality through REST, JMS and Java interfaces to client application.

At its core, the Realtime Decision Server is a configurable web application packaged as a WAR file. Distributions are available for pure web containers (like Tomcat) and for JEE 6 and JEE 7 containers.

Most capabilities on the Realtime Decision Server are configurable, and based on the concepts of extensions. Each extension can be enabled/disabled independently, allowing the user to configure the server to its need.

20.2. Business Resource Planner REST API

When the Planner capability is enabled, the Realtime Decision Server supports the following additional REST APIs. All these APIs are also available through JMS and the Java client API. Please also note:

  • To deploy the Realtime Decision Server, see chapter Realtime Decision Server from Red Hat JBoss BRMS User Guide.
  • The base URL for these will remain as the endpoint defined earlier (for example http://SERVER:PORT/kie-server/services/rest/server/).
  • All requests require the user to have the role kie-server.

  • To get a specific marshalling format, add the HTTP headers Content-Type and optional X-KIE-ContentType in the HTTP request. For example: 

    Content-Type: application/xml
X-KIE-ContentType: xstream

The example requests and responses used below presume that a KIE container is built using the optacloud example of OptaPlanner Workbench, by calling a PUT on /services/rest/server/containers/optacloud-kiecontainer-1 with this content: 

<kie-container container-id="optacloud-kiecontainer-1">
  <release-id>
    <group-id>opta</group-id>
    <artifact-id>optacloud</artifact-id>
    <version>1.0.0</version>
  </release-id>
</kie-container>

20.2.1. [GET] /containers/{containerId}/solvers

Returns the list of solvers created in the container.

Example 20.1. Example Server Response (XStream)

<org.kie.server.api.model.ServiceResponse>
<type>SUCCESS</type>
<msg>Solvers list successfully retrieved from container 'optacloud-kiecontainer-1'</msg>
<result class="org.kie.server.api.model.instance.SolverInstanceList">
  <solvers>
    <solver-instance>
      <container-id>optacloud-kiecontainer-1</container-id>
      <solver-id>solver1</solver-id>
      <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
      <status>NOT_SOLVING</status>
    </solver-instance>
    <solver-instance>
      <container-id>optacloud-kiecontainer-1</container-id>
      <solver-id>solver2</solver-id>
      <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
      <status>NOT_SOLVING</status>
    </solver-instance>
  </solvers>
</result>
</org.kie.server.api.model.ServiceResponse>

Example 20.2. Example Server Response (JSON)

{
"type" : "SUCCESS",
"msg" : "Solvers list successfully retrieved from container 'optacloud-kiecontainer-1'",
"result" : {
  "solver-instance-list" : {
    "solver" : [ {
      "status" : "NOT_SOLVING",
      "container-id" : "optacloud-kiecontainer-1",
      "solver-id" : "solver1",
      "solver-config-file" : "opta/optacloud/cloudSolverConfig.solver.xml"
    }, {
      "status" : "NOT_SOLVING",
      "container-id" : "optacloud-kiecontainer-1",
      "solver-id" : "solver2",
      "solver-config-file" : "opta/optacloud/cloudSolverConfig.solver.xml"
    } ]
  }
}
}

20.2.2. [PUT] /containers/{containerId}/solvers/{solverId}

Creates a new solver with the given {solverId} in the container {containerId}. The request’s body is a marshalled SolverInstance entity that must specify the solver configuration file.

The following is an example of the request and the corresponding response.

Example 20.3. Example Server Request (XStream)

<solver-instance>
  <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
</solver-instance>

Example 20.4. Example Server Response (XStream)

<org.kie.server.api.model.ServiceResponse>
  <type>SUCCESS</type>
  <msg>Solver 'solver1' successfully created in container 'optacloud-kiecontainer-1'</msg>
  <result class="solver-instance">
    <container-id>optacloud-kiecontainer-1</container-id>
    <solver-id>solver1</solver-id>
    <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
    <status>NOT_SOLVING</status>
  </result>
</org.kie.server.api.model.ServiceResponse>

Example 20.5. Example Server Request (JSON)

{
  "solver-config-file" : "opta/optacloud/cloudSolverConfig.solver.xml"
}

Example 20.6. Example Server Response (JSON)

{
  "type" : "SUCCESS",
  "msg" : "Solver 'solver1' successfully created in container 'optacloud-kiecontainer-1'",
  "result" : {
    "solver-instance" : {
      "container-id" : "optacloud-kiecontainer-1",
      "solver-id" : "solver1",
      "solver-config-file" : "opta/optacloud/cloudSolverConfig.solver.xml",
      "status" : "NOT_SOLVING"
    }
  }
}

20.2.3. [GET] /containers/{containerId}/solvers/{solverId}

Returns the current state of the solver {solverId} in container {containerId}.

Example 20.7. Example Server Response (XStream)

<org.kie.server.api.model.ServiceResponse>
  <type>SUCCESS</type>
  <msg>Solver 'solver1' state successfully retrieved from container 'optacloud-kiecontainer-1'</msg>
  <result class="solver-instance">
    <container-id>optacloud-kiecontainer-1</container-id>
    <solver-id>solver1</solver-id>
    <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
    <status>NOT_SOLVING</status>
  </result>
</org.kie.server.api.model.ServiceResponse>

Example 20.8. Example Server Response (JSON)

{
  "type" : "SUCCESS",
  "msg" : "Solver 'solver1' state successfully retrieved from container 'optacloud-kiecontainer-1'",
  "result" : {
    "solver-instance" : {
      "container-id" : "optacloud-kiecontainer-1",
      "solver-id" : "solver1",
      "solver-config-file" : "opta/optacloud/cloudSolverConfig.solver.xml",
      "status" : "NOT_SOLVING"
    }
  }
}

20.2.4. Start solving

Here is an example to solve an optacloud problem with 2 computers and 1 process:

Example 20.9. Example Server Request (XStream)

<solver-instance>
  <status>SOLVING</status>
  <planning-problem class="opta.optacloud.CloudSolution">
    <computerList>
      <opta.optacloud.Computer>
        <cpuPower>10</cpuPower>
        <memory>4</memory>
        <networkBandwidth>100</networkBandwidth>
        <cost>1000</cost>
      </opta.optacloud.Computer>
      <opta.optacloud.Computer>
        <cpuPower>20</cpuPower>
        <memory>8</memory>
        <networkBandwidth>100</networkBandwidth>
        <cost>3000</cost>
      </opta.optacloud.Computer>
    </computerList>
    <processList>
      <opta.optacloud.Process>
        <requiredCpuPower>1</requiredCpuPower>
        <requiredMemory>7</requiredMemory>
        <requiredNetworkBandwidth>1</requiredNetworkBandwidth>
      </opta.optacloud.Process>
    </processList>
  </planning-problem>
</solver-instance>

Notice that the response does not contain the best solution yet, because solving can take seconds, minutes, days or hours and this would time out the HTTP request:

Example 20.10. Example Server Response (XStream)

<org.kie.server.api.model.ServiceResponse>
  <type>SUCCESS</type>
  <msg>Solver 'solver1' from container 'optacloud-kiecontainer-1' successfully updated.</msg>
  <result class="solver-instance">
    <container-id>optacloud-kiecontainer-1</container-id>
    <solver-id>solver1</solver-id>
    <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
    <status>SOLVING</status>
  </result>
</org.kie.server.api.model.ServiceResponse>

Instead, it’s solving asynchronously and you need to call the bestsolution URL to get the best solution.

20.2.5. Terminate solving

For example, to terminate solving:

Example 20.11. Example Server Request (XStream)

<solver-instance>
  <status>NOT_SOLVING</status>
</solver-instance>

Example 20.12. Example Server Response (XStream)

<org.kie.server.api.model.ServiceResponse>
  <type>SUCCESS</type>
  <msg>Solver 'solver1' from container 'optacloud-kiecontainer-1' successfully updated.</msg>
  <result class="solver-instance">
    <container-id>optacloud-kiecontainer-1</container-id>
    <solver-id>solver1</solver-id>
    <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
    <status>TERMINATING_EARLY</status>
    <score class="org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore">
      <hardScore>0</hardScore>
      <softScore>-3000</softScore>
    </score>
  </result>
</org.kie.server.api.model.ServiceResponse>

This doesn’t delete the solver, the best solution can still be retrieved.

20.2.6. [GET] /containers/{containerId}/solvers/{solverId}/bestsolution

Returns the best solution found at the time the request is made. If the solver hasn’t terminated yet (so the status field is still SOLVING), it will return the best solution found up to then, but later calls can return a better solution.⁠

For example, the problem submitted above would return this solution, with the process assigned to the second computer (because the first one doesn’t have enough memory).

Example 20.13. Example Server Response (XStream)

<org.kie.server.api.model.ServiceResponse>
  <type>SUCCESS</type>
  <msg>Best computed solution for 'solver1' successfully retrieved from container 'optacloud-kiecontainer-1'</msg>
   <result class="solver-instance">
    <container-id>optacloud-kiecontainer-1</container-id>
    <solver-id>solver1</solver-id>
    <solver-config-file>opta/optacloud/cloudSolverConfig.solver.xml</solver-config-file>
    <status>SOLVING</status>
    <score class="org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore">
      <hardScore>0</hardScore>
      <softScore>-3000</softScore>
    </score>
    <best-solution class="opta.optacloud.CloudSolution">
      <score class="org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore" reference="../../score" />
      <computerList>
        <opta.optacloud.Computer>
          <cpuPower>10</cpuPower>
          <memory>4</memory>
          <networkBandwidth>100</networkBandwidth>
          <cost>1000</cost>
        </opta.optacloud.Computer>
        <opta.optacloud.Computer>
          <cpuPower>20</cpuPower>
          <memory>8</memory>
          <networkBandwidth>100</networkBandwidth>
          <cost>3000</cost>
        </opta.optacloud.Computer>
      </computerList>
      <processList>
        <opta.optacloud.Process>
          <requiredCpuPower>1</requiredCpuPower>
          <requiredMemory>7</requiredMemory>
          <requiredNetworkBandwidth>1</requiredNetworkBandwidth>
          <computer reference="../../../computerList/opta.optacloud.Computer[2]" />
        </opta.optacloud.Process>
      </processList>
    </best-solution>
  </result>
</org.kie.server.api.model.ServiceResponse>

20.2.7. [DELETE] /containers/{containerId}/solvers/{solverId}

⁠Disposes the solver {solverId} in container {containerId}. If it hasn’t terminated yet, it terminates it first.

Example 20.14. Example Server Response (XStream)

<org.kie.server.api.model.ServiceResponse>
  <type>SUCCESS</type>
  <msg>Solver 'solver1' successfully disposed from container 'optacloud-kiecontainer-1'</msg>
</org.kie.server.api.model.ServiceResponse>

Example 20.15. Example Server Response (JSON)

{
  "type" : "SUCCESS",
  "msg" : "Solver 'solver1' successfully disposed from container 'optacloud-kiecontainer-1'"
}