Solr: Is it possible to call the "concat" function in the source of the "copyField"？

For example if I define the "copyField" below, the solr will throw this exception when startup： org.apache.solr.common.SolrException: copyField source :'concat('i1', id1)' is not a glob and doesn't match any explicit field or dynamicField.

<copyField source="concat('i1', id1)" dest="test" />
<copyField source="concat('i2', id2)" dest="test" />

But "concat('i1', id1)" can set to the "fl" of the query request without any errors.

You can archive the same with the help of Update request Processors of Solr

You can use the ConcatFieldUpdateProcessorFactory :

Concatenates multiple values for fields matching the specified conditions using a configurable delimiter.

For Example :

1. Add a new updateRequestProcessorChain to solrconfig.xml:

<updateRequestProcessorChain name="concatFields">
  <processor class="solr.CloneFieldUpdateProcessorFactory"> 
      <str name="source">field1</str> 
      <str name="dest">field4</str> 
    </processor> 
  <processor class="solr.ConcatFieldUpdateProcessorFactory"> 
      <str name="fieldName">field4</str> 
      <str name="delimiter">_</str> 
    </processor>
    <processor class="solr.LogUpdateProcessorFactory" /> 
    <processor class="solr.RunUpdateProcessorFactory" />
</updateRequestProcessorChain>

2. Add that chain to the appropriate update handler

<requestHandler name="/update/csv" class="solr.UpdateRequestHandler">
         <lst name="defaults">
         <str name="stream.contentType">application/csv</str>
         <str name="update.chain">concatFields</str>    </lst> </requestHandler>

More details on the Update processors are found on the link below. Update Request Processors

Note : Restart the Solr server and to index new documents.