ServiceMix Exec

ServiceMix Exec component is used to invoke commands (executables, shell commands, shell scripts, ...). The command can be static (defined in the component endpoint descriptor) or dynamic (provided in the incoming message, including arguments).

Maven Archetype

The servicemix-exec-service-unit archetype create an Exec Service Unit:

mvn archetype:create \
  -DarchetypeGroupId=org.apache.servicemix.tooling \
  -DarchetypeArtifactId=servicemix-exec-service-unit \
  -DarchetypeVersion=2010.01 \
  -DgroupId=your.group.id \
  -DartifactId=your.artifact.id \
  -Dversion=your-version

Once you've customized the service unit, simply install the SU:

mvn install

Remember that to be deployable in ServiceMix, the ServiceUnit has to be embedded in a Service Assembly: only the Service Assembly zip file can be deployed in ServiceMix.
To add your SU in a SA, you need to define it in the dependency sets:

<dependency>
  <groupId>your.group.id</groupId>
  <artifactId>your.artifact.id</artifactId>
  <version>your-version</version>
</dependency>

Endpoint Configuration

The Exec endpoint can be very simple, waiting for command contained in the in message:

<beans xmlns="http://servicemix.apache.org/exec/1.0"
       xmlns:test="http://test">
  <exec:endpoint service="test:MyService"
                 endpoint="MyExec"/>
</beans>

You can define a fallback command if the incoming doesn't provide a command:

<beans xmlns="http://servicemix.apache.org/exec/1.0"
       xmlns:test="http://test">
   <exec:endpoint service="test:MyService"
                  endpoint="MyExec"
                  command="date"/>
</beans>

Endpoint attributes

Name	Type	Description	Required
endpoint	String	JBI Endpoint name	no (will be auto-generated if not specified)
interfaceName	QName	Interface QName implemented by the JBI endpoint	no (will be auto-generated if not specified)
service	QName	JBI Service name	no (will be auto-generated if not specified)
command	String	Fallback command	Command that will be executed if the in message doesn't provide a command.
marshaler	ExecMarshalerSupport	Marshaler to use to parse the incoming message and construct the exec command.	no (DefaultExecMarshaler by default)

How it works

ServiceMix Exec service engine acts as a provider. It supports all MEP.

When used with an InOnly MEP, the Exec component executes the command and set the exchange in DONE status.

When used with an InOut MEP, the Exec components executes the command and get the command output buffer. The command output is put in the out message and send back in the exchange.

Abstract WSDL

ServiceMix Exec endpoint exposes an abstract WSDL (in the endpoint descriptor) to define the format of exchanged message.

<?xml version="1.0" encoding="UTF-8"?>
<!--
  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements. See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership. The ASF licenses this file
  to you under the Apache License, Version 2.0 (the
  "License"); you may not use this file except in compliance
  with the License. You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing,
  software distributed under the License is distributed on an
  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  KIND, either express or implied. See the License for the
  specific language governing permissions and limitations
  under the License.
-->
<wsdl:definitions name="servicemix-exec"
    targetNamespace="http://servicemix.apache.org/exec"
    xmlns:tns="http://servicemix.apache.org/exec"
    xmlns:wsdl='http://schemas.xmlsoap.org/wsdl/'
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">

    <wsdl:types>
        <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
                targetNamespace="http://servicemix.apache.org/exec"
                xmlns:tns="http://servicemix.apache.org/exec"
                attributeFormDefault="unqualified"
                elementFormDefault="unqualified">

              <xs:complexType name="execRequest">
                <xs:sequence>
                    <xs:element name="command" type="xs:string" minOccurs="0"/>
                    <xs:element name="arguments" minOccurs="0">
                        <xs:complexType>
                            <xs:sequence>
                                <xs:element name="argument" type="xs:string" minOccurs="0" maxOccurs="unbounded"/>
                            </xs:sequence>
                        </xs:complexType>
                    </xs:element>
                </xs:sequence>
             </xs:complexType>

             <xs:complexType name="execResponse">
                <xs:sequence>
                    <xs:element name="endTime" type="xs:long"/>
                    <xs:element name="errorData" type="tns:stringBuffer" minOccurs="0"/>
                    <xs:element name="executionDuration" type="xs:long"/>
                    <xs:element name="exitCode" type="xs:int"/>
                    <xs:element name="outputData" type="tns:stringBuffer" minOccurs="0"/>
                    <xs:element name="startTime" type="xs:long"/>
                </xs:sequence>
            </xs:complexType>

            <xs:complexType name="stringBuffer" final="extension restriction">
                <xs:complexContent>
                    <xs:extension base="tns:abstractStringBuilder">
                        <xs:sequence/>
                    </xs:extension>
                </xs:complexContent>
            </xs:complexType>

            <xs:complexType name="abstractStringBuilder" abstract="true">
                <xs:sequence/>
            </xs:complexType>

        </xs:schema>
    </wsdl:types>

    <wsdl:message name="execRequest">
        <wsdl:part name="parameters" element="tns:execRequest"/>
    </wsdl:message>

    <wsdl:message name="execResponse">
        <wsdl:part name="parameters" element="tns:execResponse"/>
    </wsdl:message>

    <wsdl:portType name="ExecPortType">
        <wsdl:operation name="execute">
            <wsdl:input message="tns:execRequest"/>
            <wsdl:output message="tns:execResponse"/>
        </wsdl:operation>
    </wsdl:portType>

</wsdl:definitions>

It's possible to expose an Exec endpoint directly using a SOAP compliant BC such as ServiceMix HTTP or ServiceMix CXF-BC.
For example, using a ServiceMix HTTP endpoint, the HTTP component create a concrete WSDL (adding SOAP bindings) using the Exec abstract one. See the Exec sample.

An exec endpoint expects an ExecRequest message and provide an ExecResponse. The way to marshal/unmarshal ExecRequest and ExecResponse can be override by defining your own ExecMarshaler.

ExecRequest

The ExecRequest describes the command to execute with or without arguments. The arguments can be append directly on the command or using the dedicated attributes.

If the ExecRequest is empty (without command provided), the Exec endpoint will use the static command provided in the xbean.xml (using the command attribute). If no command is provided (neither in the ExecRequest and in the xbean.xml), the Exec endpoint throws an exception and the exchange fails.

The ExecRequest defines the following attributes:

command   - the command to execute (for example ls). The command arguments can be provided directly here (for example ls -lt).
arguments - the command arguments.

Here is an example of ExecRequest:

<?xml version="1.0" encoding="UTF-8"?>
<exec:execRequest xmlns:exec="http://servicemix.apache.org/exec">
  <command>ls</command>
  <arguments>
   <argument>-lt</argument>
   <argument>/tmp</argument>
  <arguments>
</exec:execRequest>

ExecResponse

When used with an InOut MEP, the Exec endpoint returns an ExecResponse. The ExecResponse contains all information about the command execution.

started  - contains the execution start time in millis (System.currentTimeMillis() is used).
finished - contains the time the process execution finished in millis (System.currentTimeMillis() is used).
duration - the duration in millis the execution took.
exitcode - the return code of the process (0 means all fine; != 0 means an error code).
output   - the contents of the output stream of the process.
error    - the contents of the error stream of the process.

Some words on the output and error stream contents.
It may happen that some information at the very beginning will get lost depending on how
fast the stream listeners are set up and how fast the executed process will push information to it.

Here is an example of an ExecResponse:

<?xml version="1.0" encoding="UTF-8"?>
<exec:execResponse xmlns:exec="http://servicemix.apache.org/exec">
  <started>1241756756376</started>
  <finished>1241756756390</finished>
  <duration>14</duration>
  <exitcode>0</exitcode>
  <output><![CDATA[
total 6729
-rw------- 1 jb       jb   1693752 2009-04-09 09:07 f9G0lWzx.tar.part
-rw-r--r-- 1 jb       jb         8 2009-03-27 18:27 gnome-session-manager
srwxr-xr-x 1 jb       jb         0 2009-03-26 10:56 gnome-system-monitor.jb.3619273851
drwxr-xr-x 2 jb       jb      1024 2009-04-23 08:43 hsperfdata_jb
drwxr-xr-x 2 jboss    java    1024 2009-04-17 12:46 hsperfdata_jboss
drwxr-xr-x 2 weblogic java    1024 2009-04-17 09:40 hsperfdata_weblogic
-rw-r--r-- 1 jb       jb       870 2009-03-26 10:59 jbi12672.zip
-rw-r--r-- 1 jb       jb       870 2009-03-26 10:59 jbi12673.zip
]]></output>
  <error><![CDATA[
]]></error>
</exec:execResponse>

Child pages

servicemix-exec