Extract Variables policy deployment error troubleshooting

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NothingToExtract

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
ExtractVariables [policy_name]: at least one of URIPath, QueryParam, Header, FormParam, XMLPayload, JSONPayload is mandatory. Revision:[revision_number]; APIProxy:[proxy_name]; Organization:[org_name]; Environment:[env_name].

Example error message

Error Saving Revision 2
ExtractVariables EV-XML-Age: at least one of URIPath, QueryParam, Header, FormParam, XMLPayload, JSONPayload is mandatory.

Example screenshot

Cause

If the Extract Variables Policy does not have any of the elements URIPath, QueryParam, Header, FormParam, XMLPayload, or JSONPayload, the deployment of the API Proxy fails, because there's nothing to extract.

As indicated in the error message, the Extract Variables policy must have at least one of these elements included within the policy: URIPath, QueryParam, Header, FormParam, XMLPayload, or JSONPayload.

Diagnosis

Examine the Extract Variables policy named in the error message. If the policy does not have even one of the following elements: URIPath, QueryParam, Header, FormParam, XMLPayload, or JSONPayload, then that's the cause of the error. For example, the following Extract Variables policy does not have any of the above mentioned elements:

<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
    <DisplayName>EV-XML-Age</DisplayName>
    <Properties/>
</ExtractVariables>

Since none of the mandatory elements are present in the Extract Variables policy, the deployment of the API proxy fails.

Resolution

Ensure that the Extract Variables policy has at least one of these mandatory elements: URIPath, QueryParam, Header, FormParam, XMLPayload, JSONPayload. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
  <DisplayName>EV-XML-Age</DisplayName>
  <Properties/>
  <Source>request</Source>
  <XMLPayload>
    <Namespaces/>
      <Variable name="age" type="integer">
          <XPath>/age</XPath>
      </Variable>
  </XMLPayload>
</ExtractVariables>

NONEmptyPrefixMappedToEmptyURI

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
ExtractVariables [policy_name]: Non-empty prefix [prefix_name] cannot be mapped to empty uri.

Example error message

Error Saving Revision 3
ExtractVariables EV-XML-Age: Non-empty prefix apigee cannot be mapped to empty uri.

Example screenshot

Cause

This error occurs if the Extract Variables Policy has a prefix defined in the <Namespace> element under the <XMLPayload> element, but no URI is defined.

Diagnosis

Identify the Extract Variables policy where the error occurred and the name of the prefix. You can find both of these items in the error message. For example, in the following error , the policy name is EV-XML-Age and the prefix is apigee:
```
ExtractVariables EV-XML-Age: Non-empty prefix apigee cannot be mapped to empty uri.
```

In the failed Extract Variables policy XML, verify that the name of the prefix set in the <Namespace> element under the <XMLPayload> element matches the prefix name identified in the error message (step #1 above). For example, the following policy specifies a prefix named apigee in the <Namespace> element , which matches what's in the error message:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
    <DisplayName>EV-XML-Age</DisplayName>
    <Source clearPayload="false">request</Source>
    <XMLPayload stopPayloadProcessing="false">
      <Namespaces>
        <Namespace prefix="apigee"></Namespace>
        <Namespace prefix="gmail">http://mail.google.com</Namespace>
      </Namespaces>
    <Variable name="legName" type="string">
    <XPath>/apigee:Directions/apigee:route/apigee:leg/apigee:name</Xpath>
        </Variable>
    </XMLPayload>
</ExtractVariables>

Validate if the <Namespace> element with the specific prefix identified in step #2 has a valid URI. If the URI is missing, then that is the cause of the error.

In the example Extract Variables policy shown above, notice that there's no URI corresponding to the <Namespace> element with the prefix apigee; therefore, you get the error:
```
ExtractVariables EV-XML-Age: Non-empty prefix apigee cannot be mapped to empty uri.
```

Resolution

Ensure that all the <Namespace> elements defined with a prefix have a corresponding URI in the Extract Variables policy. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
    <DisplayName>EV-XML-Age</DisplayName>
    <Source clearPayload="false">request</Source>
    <XMLPayload stopPayloadProcessing="false">
    <Namespaces>
        <Namespace prefix="apigee">http://www.apigee.com</Namespace>
        <Namespace prefix="gmail">http://mail.google.com</Namespace>
     </Namespaces>
    <Variable name="legName" type="string">
        <XPath>/apigee:Directions/apigee:route/apigee:leg/apigee:name</Xpath>
    </Variable>
    </XMLPayload>
</ExtractVariables>

DuplicatePrefix

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
ExtractVariables [policy_name]: Duplicate prefix [prefix_name].

Example error message

Error Saving Revision 2
ExtractVariables EV-XML-Age: Duplicate prefix apigee.

Example screenshot

Cause

This error occurs, if the Extract Variables Policy has the same prefix defined more than once in the <Namespace> element under the <XMLPayload> element.

For example, this error occurs since the prefix apigee is defined twice as shown below:

<Namespace prefix="apigee">http://www.apigee.com</Namespace>
<Namespace prefix="apigee">http://www.apigee.com</Namespace>

Diagnosis

Identify the Extract Variables policy where the error occurred and the name of the prefix. You can find both of these items in the error message. For example, in the following error, the policy name is EV-XML-Age and the prefix is apigee:
```
ExtractVariables EV-XML-Age: Duplicate prefix apigee.
```

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
    <DisplayName>EV-XML-Age</DisplayName>
    <Source clearPayload="false">request</Source>
    <XMLPayload stopPayloadProcessing="false">
      <Namespaces>
          <Namespace prefix="gmail">http://mail.google.com</Namespace>
          <Namespace prefix="apigee">http://www.apigee.com</Namespace>
          <Namespace prefix="apigee">http://www.apigee.com</Namespace>
      </Namespaces>
      <Variable name="legName" type="string
          <XPath>/apigee:Directions/apigee:route/apigee:leg/apigee:name</XPath>
      </Variable>
    </XMLPayload>
  </ExtractVariables>

Determine if the <Namespace> element with the specific prefix, identified in step #2 has been defined more than once. If it is defined more than once, then that is the cause of the error.

In the example Extract Variables policy shown above, notice that the <Namespace> element with the prefix apigee has been defined twice; therefore, you get the error:
```
ExtractVariables EV-XML-Age: Duplicate prefix apigee.
```

Resolution

Ensure that there is only one definition for each prefix in the <Namespace> elements in the Extract Variables policy. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
    <DisplayName>EV-XML-Age</DisplayName>
    <Source clearPayload="false">request</Source>
    <XMLPayload stopPayloadProcessing="false">
      <Namespaces>
          <Namespace prefix="apigee">http://www.apigee.com</Namespace>
          <Namespace prefix="gmail">http://mail.google.com</Namespace>
      </Namespaces>
      <Variable name="legName" type="string">
          <XPath>/apigee:Directions/apigee:route/apigee:leg/apigee:name</Xpath>
      </Variable>
    </XMLPayload>
</ExtractVariables>

NoXPathsToEvaluate

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
ExtractVariables [policy_name]:no xpaths to evaluate in variable name.

Example error message

Error Saving Revision 4
ExtractVariables Extract-Variables-1: no xpaths to evaluate in variable name.

Example screenshot

Cause

If the Extract Variables Policy does not have the <XPath> element within the <XMLPayload> element, then the deployment of the API proxy fails with the error shown above.

If you want to extract variables from an XML Payload, then an XPath child element must be specified.

Diagnosis

Identify the failed Extract Variables policy from the error message. For example, in the following error, the policy name is Extract-Variables-1:
```
ExtractVariables Extract-Variables-1: no xpaths to evaluate in variable name.
```

In the failed Extract Variables policy XML, check if there's an <XMLPayload> element without the <XPath> child element. If so, then that's the cause of the error.

For example, here's an Extract Variables policy that has an <XMLPayload> element:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>apigee</VariablePrefix>
    <XMLPayload stopPayloadProcessing="false">
        <Namespaces/>
        <Variable name="HostReachable" type="boolean">
        </Variable>
    </XMLPayload>
</ExtractVariables>

Because there is no <XPath> element present, the deployment of the API Proxy fails.

Resolution

Ensure that the Extract Variables policy has an <XPath> element defined under the <XMLPayload> element. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>apigee</VariablePrefix>
    <XMLPayload stopPayloadProcessing="false">
        <Namespaces/>
        <Variable name="HostReachable" type="boolean">
            <XPath>/isReachable</XPath>
        </Variable>
    </XMLPayload>
</ExtractVariables>

EmptyXPathExpression

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
ExtractVariables [policy_name]: XPath expression is empty in variable name.

Example error message

Error Saving Revision 6
ExtractVariables Extract-Variables-1: XPath expression is empty in variable name.

Example screenshot

Cause

If the Extract Variables Policy has an empty <XPath> expression within the <XMLPayload> element, then the deployment of the API proxy fails.

Diagnosis

Identify the failed Extract Variables policy from the error message. For example, in the following error, the policy name is Extract-Variables-1:
```
ExtractVariables Extract-Variables-1: no xpaths to evaluate in variable name.
```

In the failed Extract Variables policy XML, determine if there's an <XMLPayload> element with an empty <XPath> child element. If so, then that's the cause of the error.

For example, here's an Extract Variables policy that has an <XMLPayload> element:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>apigee</VariablePrefix>
    <XMLPayload stopPayloadProcessing="false">
        <Namespaces/>
        <Variable name="address" type="string">
            <XPath></XPath>
        </Variable>
    </XMLPayload>
</ExtractVariables>

Because there is an empty <XPath> element within the <XMLPayload> element, the deployment of the API Proxy fails.

Resolution

Ensure that the Extract Variables policy has a non-empty and valid <XPath> element defined under the <XMLPayload> element. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>apigee</VariablePrefix>
    <XMLPayload stopPayloadProcessing="false">
        <Namespaces/>
        <Variable name="address" type="string">
            <XPath>/address</XPath>
        </Variable>
    </XMLPayload>
</ExtractVariables>

NoJSONPathsToEvaluate

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
ExtractVariables [policy_name]:no jsonpaths to evaluate in variable name.

Example error message

Error Saving Revision 6
ExtractVariables Extract-Variables-1: no jsonpaths to evaluate in variable name.

Example screenshot

Cause

If the Extract Variables Policy does not have the <JSONPath> element within the <JSONPayload> element, then the deployment of the API proxy fails with the error shown above.

If you want to extract variables from a JSON Payload, then the JSONPath child element is required.

Diagnosis

Identify the failed Extract Variables policy from the error message. For example, in the following error, the policy name is Extract-Variables-1:
```
ExtractVariables Extract-Variables-1: no jsonpaths to evaluate in variable name.
```

In the failed Extract Variables policy XML, determine if there's a <JSONPayload> element without the required <JSONPath> child element. If so, then that's the cause of the error.

For example, here's an Extract Variables policy that has <JSONPayload> element:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <JSONPayload>
        <Variable name="title">
        </Variable>
    </JSONPayload>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>apigee</VariablePrefix>
</ExtractVariables>

Because there is no <JSONPath> child element defined under the <JSONPayload> element, the deployment of the API Proxy fails.

Resolution

Ensure that the Extract Variables policy has a <JSONPath> element defined under the <JSONPayload> element. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <JSONPayload>
        <Variable name="title">
            <JSONPath>$.book.title</JSONPath>
        </Variable>
    </JSONPayload>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>apigee</VariablePrefix>
</ExtractVariables>

EmptyJSONPathExpression

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
ExtractVariables [policy_name]: JSONPath expression is empty in variable name.

Example error message

Error Saving Revision 6
ExtractVariables Extract-Variables-1: JSONPath expression is empty in variable name.

Example screenshot

Cause

If the Extract Variables Policy has an empty <JSONPath> expression within the <JSONPayload> element, then the deployment of the API proxy fails.

Diagnosis

Identify the failed Extract Variables policy from the error message. For example, in the following error, the policy name is Extract-Variables-1:
```
ExtractVariables Extract-Variables-1: JSONPath expression is empty in variable name.
```

In the failed Extract Variables policy XML, verify if there's a <JSONPayload> element with an empty <JSONPath> child element. If so, then that's the cause of the error.

For example, here's an Extract Variables policy that has a <JSONPayload> element:

    <ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
        <DisplayName>Extract Variables-1</DisplayName>
        <Properties/>
        <JSONPayload>
            <Variable name="account_number" type="integer">
                <JSONPath></JSONPath>
            </Variable>
        </JSONPayload>
        <Source clearPayload="false">request</Source>
        <VariablePrefix>apigee</VariablePrefix>
    </ExtractVariables>

Because there is an empty <JSONPath> element within the <JSONPayload> element, the deployment of the API Proxy fails.

Resolution

Ensure that the Extract Variables policy has a non-empty and valid <JSONPath> element defined under the <JSONPayload> element. For example:

<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <JSONPayload>
        <Variable name="account_number" type="integer">
           <JSONPath>$.account.number</JSONPath>
        </Variable>
    </JSONPayload>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>apigee</VariablePrefix>
</ExtractVariables>

MissingName

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
Error occurred while validation of bean [policy_name].xml Reason: - Required attribute name is missing in [element_name]

Example error message

Error Saving Revision 6
Error occurred while validation of bean Extract-Variables-1.xml. Reason: - Required attribute name is missing in Variable

Example screenshot

Cause

If the Extract Variables Policy does not have the name attribute in any of the policy elements like QueryParam, Header, FormParam or Variable, where it is required, then the deployment of the API proxy fails.

For example, this error occurs if the name attribute is missing in a Variable element.

Diagnosis

Identify the name of the Extract Variables policy where the error occurred and the element where the name attribute is missing. You can find these items in the error message. For example, in the following error, the policy name is Extract-Variables-1 and the element name is Variable:
```
Error occurred while validation of bean Extract-Variables-1.xml. Reason: - Required attribute name is missing in Variable
```
In the failed Extract Variables policy XML, check that all the elements with the name determined from step #1 above have a name attribute. If there's any element where the name attribute is missing, then that is the cause of the error.

For example, the following Extract Variables policy has the <Variable> element defined:
```
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Variable type="boolean">
        <Pattern>{isAccountActive}</Pattern>
    </Variable>
</ExtractVariables>
```
Notice that the name attribute is missing in the Variable element, so the deployment of the API Proxy fails.

Resolution

Ensure that the Extract Variables Policy contains the required name attribute, for the elements QueryParam, Header, FormParam , or Variable. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Variable name="account_active" type="boolean">
        <Pattern>{isAccountActive}</Pattern>
    </Variable>
</ExtractVariables>

PatternWithoutVariable

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Saving Revision [revision_number]
Pattern [pattern] should have at least one variable in ExtractVariables stepDefinition [policy_name]

Example error message

Error Saving Revision 7
Pattern /a/b/ should have at least one variable in ExtractVariables stepDefinition ExtractVariables-1.

Example screenshot

Cause

If the Extract Variables Policy does not have a variable specified within the <Pattern> element, then the deployment of the API proxy fails. The <Pattern> element requires the name of the variable in which extracted data will be stored.

Diagnosis

Identify the name of the Extract Variables policy where the error occurred and the pattern for which the Variable is missing. You can find these items from the error message. For example, in the following error, the policy name is Extract-Variables-1 and the element name is /a/b:
```
Pattern /a/b/ should have at least one variable in ExtractVariables stepDefinition ExtractVariables-1.
```

In the failed Extract Variables policy XML, verify that the pattern set in the <Pattern> element matches the pattern identified in the error message (step #1 above). For example, the following policy specifies a pattern /a/b, which matches what's in the error message:

For example, here's an Extract Variables policy that has three <Pattern> elements:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables name="ExtractVariables-1">
   <Source>request</Source>
   <URIPath>
      <Pattern ignoreCase="true">/a/{pathSeg}</Pattern>
      <Pattern ignoreCase="true">/a/b/</Pattern>
      <Pattern ignoreCase="true">/a/b/c/{pathSeg}</Pattern>
   </URIPath>
   <VariablePrefix>urirequest</VariablePrefix>
</ExtractVariables>

Check if the <Pattern> element identified in step #2 does not have a variable. Variables must be enclosed in curly braces. If the pattern does not have a variable, then that is the cause of the error.

The <Pattern> element having the pattern /a/b does not include a variable; therefore, the deployment of the API Proxy fails
```
<Pattern ignoreCase="true">/a/b/</Pattern>
```

Resolution

Ensure any <Pattern> elements include a variable (a name enclosed in curly braces). For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables name="ExtractVariables-1">
   <Source>request</Source>
   <URIPath>
      <Pattern ignoreCase="true">/a/{pathSeg}</Pattern>
      <Pattern ignoreCase="true">/a/b/{pathSeg}</Pattern>
      <Pattern ignoreCase="true">/a/b/c/{pathSeg}</Pattern>
   </URIPath>
   <VariablePrefix>urirequest</VariablePrefix>
</ExtractVariables>

CannotBeConvertedToNodeset

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Deploying Revision [revision_number]
ExtractVariables [policy_name]: Result of xpath [policy_name] cannot be converted to nodeset. Context Revision:[revision_number]; APIProxy:[proxy_name]; Organization:[org_name]; Environment:[env_name].

Example error message

Error Deploying Revision 4 to test
ExtractVariables Extract-Variables-1: Result of xpath 123 cannot be converted to nodeset. Context Revision:4;APIProxy:EV-XML;Organization:aprabhashankar-eval;Environment:test.

Example screenshot

Cause

If the Extract Variables Policy has an <XPath> expression where the <Variable> type is defined as nodeset, but the expression cannot be converted to nodeset, then the deployment of the API proxy fails.

Diagnosis

Identify the Extract Variables policy where the error occurred and the XPath that cannot be converted to nodeset. You can find both of these items in the error message. For example, in the following error , the policy name is Extract-Variables-1 and the XPath is 123.
```
ExtractVariables Extract-Variables-1: Result of xpath 123 cannot be converted to nodeset. Context Revision:4;APIProxy:EV-XML;Organization:aprabhashankar-eval;Environment:test.
```

In the failed Extract Variables policy XML, verify that the XPath set in the <XPath> element matches the XPath identified in the error message (step #1 above). For example, the following policy specifies the as 123, which matches what's in the error message:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>visitor</VariablePrefix>
    <XMLPayload stopPayloadProcessing="false">
        <Namespaces/>
        <Variable name="age" type="nodeset">
            <XPath>123</XPath>
        </Variable>
    </XMLPayload>
</ExtractVariables>

Examine the type of the <Variable> element corresponding to the <XPath> identified in step #2 above. If the <Variable> type is nodeset, then that's the cause of the error.

Notice that the <XPath> expression is 123 in the example Extract Variables policy.
```
<XPath>123</XPath>
```
The expression 123 cannot be converted to nodeset. So, the deployment of the API Proxy fails.

Resolution

Ensure that the <XPath> expressions used in the Extract Variables policy can be converted to nodeset if the <Variable> type is defined as nodeset. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extract-Variables-1">
    <DisplayName>Extract Variables-1</DisplayName>
    <Properties/>
    <Source clearPayload="false">request</Source>
    <VariablePrefix>visitor</VariablePrefix>
    <XMLPayload stopPayloadProcessing="false">
        <Namespaces/>
        <Variable name="age" type="nodeset">
            <XPath>/visitor/age</XPath>
        </Variable>
    </XMLPayload>
</ExtractVariables>

InvalidPattern

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Deploying Revision [revision_number]
Pattern [pattern] is invalid in ExtractVariables stepDefinition [policy_name]

Example error message

Error Deploying Revision 18 to test
Pattern {*} is invalid in ExtractVariables stepDefinition ExtractVariables-2.

Example screenshot

Cause

If the <Pattern> element definition is invalid in any of the elements like URIPath, QueryParam, Header, FormParam, XMLPayload or JSONPayload within the Extract Variables Policy, then the deployment of the API proxy fails.

The Pattern element is considered invalid if it doesn't include a variable. For more information about pattern matching, see About matching and variable creation.

Diagnosis

Identify the failing Extract Variables policy from the error message. For example, in the following error, the policy name is Extract-Variables-2:
```
Pattern {*} is invalid in ExtractVariables stepDefinition ExtractVariables-2.
```

In the failed Extract Variables policy XML, check if any of these elements are present and include a <Pattern> element.: URIPath, QueryParam, Header, FormParam, XMLPayload or JSONPayload.

For example, here's an example Extract Variables policy with a <Pattern> element within <QueryParam> element:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables name="ExtractVariables-2">
    <DisplayName>ExtractVariables-2</DisplayName>
    <Source>request</Source>
    <QueryParam name="code">
        <Pattern ignoreCase="true">{*}</Pattern>
    </QueryParam>
    <VariablePrefix>queryinfo</VariablePrefix>
</ExtractVariables>

Examine the definition of each of the <Pattern> elements. If there's any <Pattern> element with an invalid definition, then that is the cause of the error.

In the example Extract Variables policy shown above, notice that the <Pattern> definition within the <QueryParam> element is invalid; therefore, the deployment of the API Proxy fails. See also About matching and variable creation
```
<Pattern ignoreCase="true">{*}</Pattern>
```

Resolution

Ensure that the <Pattern> element definition within the elements URIPath, QueryParam, Header, FormParam, XMLPayload or JSONPayload in the Extract Variables policy is valid. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables name="ExtractVariables-2">
    <DisplayName>Extract a value from a query parameter</DisplayName>
    <Source>request</Source>
    <QueryParam name="code">
        <Pattern ignoreCase="true">{code}</Pattern>
    </QueryParam>
    <VariablePrefix>queryinfo</VariablePrefix>
</ExtractVariables>

XPathCompilationFailed

Error message

Deployment of the API proxy through either the Edge UI or Edge management API fails with this error message:

Error Deploying Revision [revision_number]
ExtractVariables [policy_name]: Failed to compile xpath [xpath] Context Revision:[revision_number]; APIProxy:[proxy_name]; Organization:[org_name]; Environment:[env_name].

Example error message

Error Deploying Revision 1 to test
ExtractVariables EV-XML-Age: Failed to compile xpath /apigee:Directions/apigee:route/apigee:leg/apigee:name. Context Revision:1;APIProxy:EV-XML;Organization:aprabhashankar-eval;Environment:test.

Example screenshot

Cause

If the prefix or the value used in the <XPath> element is not part of any of the declared namespaces in the Extract Variables Policy, then the deployment of the API proxy fails.

You can find more information about namespaces, XPath and prefix in XML Namespaces and How They Affect XPath and XSLT.

Diagnosis

Identify the Extract Variables policy where the error occurred and the XPath that could not be compiled. You can find both of these items in the error message. For example, in the following error , the policy name is EV-XML-Age and the xpath is /apigee:Directions/apigee:route/apigee:leg/apigee:name.
```
ExtractVariables EV-XML-Age: Failed to compile xpath /apigee:Directions/apigee:route/apigee:leg/apigee:name. Context Revision:1;APIProxy:EV-XML;Organization:aprabhashankar-eval;Environment:test.
```

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
  <DisplayName>EV-XML-Age</DisplayName>
  <Source clearPayload="false">request</Source>
  <XMLPayload stopPayloadProcessing="false">
    <Namespaces>
        <Namespace prefix="gmail">http://mail.google.com</Namespace>
    </Namespaces>
    <Variable name="legName" type="string">
    <XPath>/apigee:Directions/apigee:route/apigee:leg/apigee:name</XPath>
        </Variable>
  </XMLPayload>
</ExtractVariables>

Examine the <Namespaces> and <XPath> elements in the Extract Variables policy. If the specific <XPath> indicated in the error message uses a prefix or value that is not part of the namespaces declared in the Extract Variables policy, then that is the cause of the error.

Notice that the specific <XPath> uses the prefix apigee in the example Extract Variables policy.
```
<XPath>/apigee:Directions/apigee:route/apigee:leg/apigee:name</XPath>
```
However, the prefix apigee is not defined in any of the <Namespace> elements; therefore, the compilation of <XPath> fails leading to deployment failure.

Resolution

Ensure all the namespaces that are being used in <XPath> elements are declared in the Extract Variables Policy. For example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-XML-Age">
  <DisplayName>EV-XML-Age</DisplayName>
  <Source clearPayload="false">request</Source>
  <XMLPayload stopPayloadProcessing="false">
    <Namespaces>
        <Namespace prefix="apigee">http://www.apigee.com</Namespace>
        <Namespace prefix="gmail">http://mail.google.com</Namespace>
    </Namespaces>
    <Variable name="legName" type="string">
        <XPath>/apigee:Directions/apigee:route/apigee:leg/apigee:name</XPath>
    </Variable>
  </XMLPayload>
</ExtractVariables>