Name

cx:pipeline-messages — Accesses pipeline message output.

Synopsis

XML Calabash maintains a buffer of messages generated by the pipeline. This step gives the pipeline access to those messages.

Output portPrimarySequenceContent types
result✔   
Option nameTypeDefault value
clearxs:booleanfalse()
levelxs:string?()
This is an extension step; to use it, your pipeline must include its declaration. For example, by including the extension library with an import at the top of your pipeline:
<p:import href="https://xmlcalabash.com/ext/library/pipeline-messages.xpl"/>
Declaration
1 |<p:declare-step xmlns:p="http://www.w3.org/ns/xproc">
  |   <p:option name="level" as="xs:string?" select="()"/>
  |   <p:option name="clear" as="xs:boolean" select="false()"/>
  |   <p:output port="result"/>
5 |</p:declare-step>

Description

XML Calabash message buffer includes both the messages generated by the pipeline itself, as well as the messages generated by steps. For example, p:xsl-message output appears in the buffer.

A pipeline can access the messages with the cx:pipeline-messages step. This step returns all of the messages in the buffer as a cx:messages document. Each message appears in a cx:message element.

<cx:message
  level = TRACE|DEBUG|INFO|WARN|ERRORThe logging level.
  message = stringThe message text.
  date = dateTimeThe message timestamp (local time).
  {any-name} = stringAny additional attributes are allowed.
 />

By default, XML Calabash keeps a buffer of the last 32 messages. If the clear option is true, the message buffer will be discarded after returning the messages.

The cx:pipeline-messages step has no inputs. It will almost certainly be necessary to use depends to control when the step runs. (A step with no inputs and no dependencies is likely to run very early, perhaps before any messages have even been generated.)

Examples

Here’s a short pipeline that applies an identity transform using p:xslt.

 1 |<p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
   |                xmlns:cx="http://xmlcalabash.com/ns/extensions"
   |                version="3.0">
   |  <p:import href="https://xmlcalabash.com/ext/library/pipeline-messages.xpl"/>
 5 | 
   |  <p:input port="source"/>
   |  <p:output port="result"
   |            serialization="map { 'method': 'xml', 'indent': 'yes' }"/>
   | 
10 |  <p:xslt name="xslt">
   |    <p:with-input port="stylesheet">
   |      <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
   |                      xmlns:xs="http://www.w3.org/2001/XMLSchema"
   |                      exclude-result-prefixes="xs"
15 |                      version="3.0">
   |        <xsl:mode on-no-match="shallow-copy"/>
   |        <xsl:template match="/" name="xsl:initial-template">
   | 
   |          <xsl:message select="'Ran an identity transform.'"/>
20 | 
   |          <xsl:apply-templates/>
   |        </xsl:template>
   |      </xsl:stylesheet>
   |    </p:with-input>
25 |  </p:xslt>
   | 
   |  <cx:pipeline-messages p:depends="xslt" level="info"/>
   |</p:declare-step>

Observe how the xsl:message appears in the pipeline messages:

 1 |<?xml version="1.0" encoding="UTF-8"?>
   |<cx:messages xmlns:cx="http://xmlcalabash.com/ns/extensions">
   |   <cx:message code="Q{http://www.w3.org/2005/xqt-errors}XTMM9000"
   |               step-name="xslt"
 5 |               system-identifier="file:/home/runner/work/xmlcalabash3/xmlcalabash3/documentation/src/examples/xpl/messages.xpl"
   |               line-number="19"
   |               column-number="61"
   |               level="INFO"
   |               message="Ran an identity transform."
10 |               date="2025-03-16T15:49:45.591347536"/>
   |</cx:messages>