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      Config API

      The Config API enables manipulating various aspects of your solrconfig.xml using REST-like API calls.

      This feature is enabled by default and works similarly in both SolrCloud and standalone mode. Many commonly edited properties (such as cache sizes and commit settings) and request handler definitions can be changed with this API.

      When using this API, solrconfig.xml is not changed. Instead, all edited configuration is stored in a file called configoverlay.json. The values in configoverlay.json override the values in solrconfig.xml.

      Config API Endpoints

      All Config API endpoints are collection-specific, meaning this API can inspect or modify the configuration for a single collection at a time.

      • collection/config: retrieve the full effective config, or modify the config. Use GET to retrieve and POST for executing commands.

      • collection/config/overlay: retrieve the details in the configoverlay.json only, removing any options defined in solrconfig.xml directly or implicitly through defaults.

      • collection/config/params: create parameter sets that can override or take the place of parameters defined in solrconfig.xml. See Request Parameters API for more information about this endpoint.

      Retrieving the Config

      All configuration items can be retrieved by sending a GET request to the /config endpoint:

      V1 API

      http://localhost:8983/solr/techproducts/config

      V2 API

      http://localhost:8983/api/collections/techproducts/config

      The response will be the Solr configuration resulting from merging settings in configoverlay.json with those in solrconfig.xml.

      It’s possible to restrict the returned config to a top-level section, such as, query, requestHandler or updateHandler. To do this, append the name of the section to the config endpoint. For example, to retrieve configuration for all request handlers:

      V1 API

      http://localhost:8983/solr/techproducts/config/requestHandler

      V2 API

      http://localhost:8983/api/collections/techproducts/config/requestHandler

      The output will be details of each request handler defined in solrconfig.xml, all defined implicitly by Solr, and all defined with this Config API stored in configoverlay.json. To see the configuration for implicit request handlers, add expandParams=true to the request. See the documentation for the implicit request handlers for examples using this command.

      The available top-level sections that can be added as path parameters are: query, requestHandler, searchComponent, updateHandler, queryResponseWriter, initParams, znodeVersion, listener, directoryFactory, indexConfig, and codecFactory.

      To further restrict the request to a single component within a top-level section, use the componentName request parameter.

      For example, to return configuration for the /select request handler:

      V1 API

      http://localhost:8983/solr/techproducts/config/requestHandler?componentName=/select

      V2 API

      http://localhost:8983/api/collections/techproducts/config/requestHandler?componentName=/select

      The output of this command will look similar to:

      {
        "config":{"requestHandler":{"/select":{
              "name": "/select",
              "class": "solr.SearchHandler",
              "defaults":{
                "echoParams": "explicit",
                "rows":10,
                "preferLocalShards":false
              }}}}
      }

      The ability to restrict to objects within a top-level section is limited to request handlers (requestHandler), search components (searchComponent), and response writers (queryResponseWriter).

      Commands to Modify the Config

      This API uses specific commands with POST requests to tell Solr what property or type of property to add to or modify in configoverlay.json. The commands are passed with the data to add or modify the property or component.

      The Config API commands for modifications are categorized into 3 types, each of which manipulate specific data structures in solrconfig.xml. These types are:

      Commands for Common Properties

      The common properties are those that are frequently customized in a Solr instance. They are manipulated with two commands:

      • set-property: Set a well known property. The names of the properties are predefined and fixed. If the property has already been set, this command will overwrite the previous setting.

      • unset-property: Remove a property set using the set-property command.

      The properties that can be configured with set-property and unset-property are predefined and listed below. The names of these properties are derived from their XML paths as found in solrconfig.xml.

      Update Handler Settings

      See UpdateHandlers in SolrConfig for defaults and acceptable values for these settings.

      • updateHandler.autoCommit.maxDocs

      • updateHandler.autoCommit.maxTime

      • updateHandler.autoCommit.openSearcher

      • updateHandler.autoSoftCommit.maxDocs

      • updateHandler.autoSoftCommit.maxTime

      • updateHandler.commitWithin.softCommit

      • updateHandler.indexWriter.closeWaitsForMerges

      Query Settings

      See Query Settings in SolrConfig for defaults and acceptable values for these settings.

      Caches and Cache Sizes

      • query.filterCache.class

      • query.filterCache.size

      • query.filterCache.initialSize

      • query.filterCache.autowarmCount

      • query.filterCache.maxRamMB

      • query.filterCache.regenerator

      • query.queryResultCache.class

      • query.queryResultCache.size

      • query.queryResultCache.initialSize

      • query.queryResultCache.autowarmCount

      • query.queryResultCache.maxRamMB

      • query.queryResultCache.regenerator

      • query.documentCache.class

      • query.documentCache.size

      • query.documentCache.initialSize

      • query.documentCache.autowarmCount

      • query.documentCache.regenerator

      • query.fieldValueCache.class

      • query.fieldValueCache.size

      • query.fieldValueCache.initialSize

      • query.fieldValueCache.autowarmCount

      • query.fieldValueCache.regenerator

      Query Sizing and Warming

      • query.maxBooleanClauses

      • query.enableLazyFieldLoading

      • query.useFilterForSortedQuery

      • query.queryResultWindowSize

      • query.queryResultMaxDocCached

      RequestDispatcher Settings

      See RequestDispatcher in SolrConfig for defaults and acceptable values for these settings.

      • requestDispatcher.handleSelect

      • requestDispatcher.requestParsers.enableRemoteStreaming

      • requestDispatcher.requestParsers.enableStreamBody

      • requestDispatcher.requestParsers.multipartUploadLimitInKB

      • requestDispatcher.requestParsers.formdataUploadLimitInKB

      • requestDispatcher.requestParsers.addHttpRequestToContext

      Examples of Common Properties

      Constructing a command to modify or add one of these properties follows this pattern:

      {"set-property":{"<property>": "<value>"}}

      A request to increase the updateHandler.autoCommit.maxTime would look like:

      V1 API

      curl -X POST -H 'Content-type: application/json' -d '{"set-property":{"updateHandler.autoCommit.maxTime":15000}}' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type: application/json' -d '{"set-property":{"updateHandler.autoCommit.maxTime":15000}}' http://localhost:8983/api/collections/techproducts/config

      You can use the config/overlay endpoint to verify the property has been added to configoverlay.json:

      V1 API

      curl http://localhost:8983/solr/techproducts/config/overlay?omitHeader=true

      V2 API

      curl http://localhost:8983/api/collections/techproducts/config/overlay?omitHeader=true

      Output:

      {
        "overlay": {
          "znodeVersion": 1,
          "props": {
            "updateHandler": {
              "autoCommit": {"maxTime": 15000}
            }
      }}}

      To unset the property:

      V1 API

      curl -X POST -H 'Content-type: application/json' -d '{"unset-property": "updateHandler.autoCommit.maxTime"}' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type: application/json' -d '{"unset-property": "updateHandler.autoCommit.maxTime"}' http://localhost:8983/api/collections/techproducts/config

      Commands for Handlers and Components

      Request handlers, search components, and other types of localized Solr components (such as query parsers, update processors, etc.) can be added, updated and deleted with specific commands for the type of component being modified.

      The syntax is similar in each case: add-<component-name>, update-<component-name>, and delete-<component-name>. The command name is not case sensitive, so Add-RequestHandler, ADD-REQUESTHANDLER and add-requesthandler are equivalent.

      In each case, add- commands add a new configuration to configoverlay.json, which will override any other settings for the component in solrconfig.xml.

      update- commands overwrite an existing setting in configoverlay.json.

      delete- commands remove the setting from configoverlay.json.

      Settings removed from configoverlay.json are not removed from solrconfig.xml if they happen to be duplicated there.

      The full list of available commands follows below:

      Basic Commands for Components

      These commands are the most commonly used:

      • add-requesthandler

      • update-requesthandler

      • delete-requesthandler

      • add-searchcomponent

      • update-searchcomponent

      • delete-searchcomponent

      • add-initparams

      • update-initparams

      • delete-initparams

      • add-queryresponsewriter

      • update-queryresponsewriter

      • delete-queryresponsewriter

      Advanced Commands for Components

      These commands allow registering more advanced customizations to Solr:

      • add-queryparser

      • update-queryparser

      • delete-queryparser

      • add-valuesourceparser

      • update-valuesourceparser

      • delete-valuesourceparser

      • add-transformer

      • update-transformer

      • delete-transformer

      • add-updateprocessor

      • update-updateprocessor

      • delete-updateprocessor

      • add-queryconverter

      • update-queryconverter

      • delete-queryconverter

      • add-listener

      • update-listener

      • delete-listener

      • add-runtimelib

      • update-runtimelib

      • delete-runtimelib

      Examples of Handler and Component Commands

      To create a request handler, we can use the add-requesthandler command:

      curl -X POST -H 'Content-type:application/json'  -d '{
        "add-requesthandler": {
          "name": "/mypath",
          "class": "solr.DumpRequestHandler",
          "defaults":{ "x": "y" ,"a": "b", "rows":10 },
          "useParams": "x"
        }
      }' http://localhost:8983/solr/techproducts/config

      V1 API

      curl -X POST -H 'Content-type:application/json' -d '{
        "add-requesthandler": {
          "name": "/mypath",
          "class": "solr.DumpRequestHandler",
          "defaults": { "x": "y" ,"a": "b", "rows":10 },
          "useParams": "x"
        }
      }' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type:application/json' -d '{
        "add-requesthandler": {
          "name": "/mypath",
          "class": "solr.DumpRequestHandler",
          "defaults": { "x": "y" ,"a": "b", "rows":10 },
          "useParams": "x"
        }
      }' http://localhost:8983/api/collections/techproducts/config

      Make a call to the new request handler to check if it is registered:

      curl http://localhost:8983/solr/techproducts/mypath?omitHeader=true

      And you should see the following as output:

      {
        "params":{
          "indent": "true",
          "a": "b",
          "x": "y",
          "rows": "10"},
        "context":{
          "webapp": "/solr",
          "path": "/mypath",
          "httpMethod": "GET"}}

      To update a request handler, you should use the update-requesthandler command:

      V1 API

      curl -X POST -H 'Content-type:application/json' -d '{
        "update-requesthandler": {
          "name": "/mypath",
          "class": "solr.DumpRequestHandler",
          "defaults": {"x": "new value for X", "rows": "20"},
          "useParams": "x"
        }
      }' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type:application/json' -d '{
        "update-requesthandler": {
          "name": "/mypath",
          "class": "solr.DumpRequestHandler",
          "defaults": {"x": "new value for X", "rows": "20"},
          "useParams": "x"
        }
      }' http://localhost:8983/api/collections/techproducts/config

      As a second example, we’ll create another request handler, this time adding the 'terms' component as part of the definition:

      V1 API

      curl -X POST -H 'Content-type:application/json' -d '{
        "add-requesthandler": {
          "name": "/myterms",
          "class": "solr.SearchHandler",
          "defaults": {"terms": true, "distrib":false},
          "components": ["terms"]
        }
      }' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type:application/json' -d '{
        "add-requesthandler": {
          "name": "/myterms",
          "class": "solr.SearchHandler",
          "defaults": {"terms": true, "distrib":false},
          "components": ["terms"]
        }
      }' http://localhost:8983/api/collections/techproducts/config

      Commands for User-Defined Properties

      Solr lets users templatize the solrconfig.xml using the place holder format ${variable_name:default_val}. You could set the values using system properties, for example, -Dvariable_name= my_customvalue. The same can be achieved during runtime using these commands:

      • set-user-property: Set a user-defined property. If the property has already been set, this command will overwrite the previous setting.

      • unset-user-property: Remove a user-defined property.

      The structure of the request is similar to the structure of requests using other commands, in the format of "command":{"variable_name": "property_value"}. You can add more than one variable at a time if necessary.

      For more information about user-defined properties, see the section User defined properties in core.properties.

      See also the section Creating and Updating User-Defined Properties below for examples of how to use this type of command.

      Creating and Updating User-Defined Properties

      This command sets a user property.

      V1 API

      curl -X POST -H 'Content-type:application/json' -d '{"set-user-property": {"variable_name": "some_value"}}' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type:application/json' -d '{"set-user-property": {"variable_name": "some_value"}}' http://localhost:8983/api/collections/techproducts/config

      Again, we can use the /config/overlay endpoint to verify the changes have been made:

      V1 API

      curl http://localhost:8983/solr/techproducts/config/overlay?omitHeader=true

      V2 API

      curl http://localhost:8983/api/collections/techproducts/config/overlay?omitHeader=true

      And we would expect to see output like this:

      {"overlay":{
         "znodeVersion":5,
         "userProps":{
           "variable_name": "some_value"}}
      }

      To unset the variable, issue a command like this:

      V1 API

      curl -X POST -H 'Content-type:application/json' -d '{"unset-user-property": "variable_name"}' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type:application/json' -d '{"unset-user-property": "variable_name"}' http://localhost:8983/api/collections/techproducts/config

      What about updateRequestProcessorChain?

      The Config API does not let you create or edit updateRequestProcessorChain elements. However, it is possible to create updateProcessor entries and use them by name to create a chain.

      For example:

      V1 API

      curl -X POST -H 'Content-type:application/json' -d '{"add-updateprocessor":
        {"name": "firstFld",
        "class": "solr.FirstFieldValueUpdateProcessorFactory",
        "fieldName": "test_s"}
      }' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type:application/json' -d '{"add-updateprocessor":
        {"name": "firstFld",
        "class": "solr.FirstFieldValueUpdateProcessorFactory",
        "fieldName": "test_s"}
      }' http://localhost:8983/api/collections/techproducts/config

      You can use this directly in your request by adding a parameter in the updateRequestProcessorChain for the specific update processor called processor=firstFld.

      How to Map solrconfig.xml Properties to JSON

      By using this API, you will be generating JSON representations of properties defined in solrconfig.xml. To understand how properties should be represented with the API, let’s take a look at a few examples.

      Here is what a request handler looks like in solrconfig.xml:

      <requestHandler name="/query" class="solr.SearchHandler">
        <lst name="defaults">
          <str name="echoParams">explicit</str>
          <int name="rows">10</str>
        </lst>
      </requestHandler>

      The same request handler defined with the Config API would look like this:

      {
        "add-requesthandler":{
          "name": "/query",
          "class": "solr.SearchHandler",
          "defaults":{
            "echoParams": "explicit",
            "rows": 10
          }
        }
      }

      The QueryElevationComponent searchComponent in solrconfig.xml looks like this:

      <searchComponent name="elevator" class="solr.QueryElevationComponent" >
        <str name="queryFieldType">string</str>
        <str name="config-file">elevate.xml</str>
      </searchComponent>

      And the same searchComponent with the Config API:

      {
        "add-searchcomponent":{
          "name": "elevator",
          "class": "solr.QueryElevationComponent",
          "queryFieldType": "string",
          "config-file": "elevate.xml"
        }
      }

      Removing the searchComponent with the Config API:

      {
        "delete-searchcomponent": "elevator"
      }

      A simple highlighter looks like this in solrconfig.xml (example has been truncated for space):

      <searchComponent class="solr.HighlightComponent" name="highlight">
          <highlighting>
            <fragmenter name="gap"
                        default="true"
                        class="solr.highlight.GapFragmenter">
              <lst name="defaults">
                <int name="hl.fragsize">100</int>
              </lst>
            </fragmenter>
      
            <formatter name="html"
                       default="true"
                       class="solr.highlight.HtmlFormatter">
              <lst name="defaults">
                <str name="hl.simple.pre"><![CDATA[<em>]]></str>
                <str name="hl.simple.post"><![CDATA[</em>]]></str>
              </lst>
            </formatter>
      
            <encoder name="html" class="solr.highlight.HtmlEncoder" />
      ...
          </highlighting>

      The same highlighter with the Config API:

      {
          "add-searchcomponent": {
              "name": "highlight",
              "class": "solr.HighlightComponent",
              "": {
                  "gap": {
                      "default": "true",
                      "name": "gap",
                      "class": "solr.highlight.GapFragmenter",
                      "defaults": {
                          "hl.fragsize": 100
                      }
                  }
              },
              "html": [{
                  "default": "true",
                  "name": "html",
                  "class": "solr.highlight.HtmlFormatter",
                  "defaults": {
                      "hl.simple.pre": "before-",
                      "hl.simple.post": "-after"
                  }
              }, {
                  "name": "html",
                  "class": "solr.highlight.HtmlEncoder"
              }]
          }
      }

      Set autoCommit properties in solrconfig.xml:

      <autoCommit>
        <maxTime>15000</maxTime>
        <openSearcher>false</openSearcher>
      </autoCommit>

      Define the same properties with the Config API:

      {
        "set-property": {
          "updateHandler.autoCommit.maxTime":15000,
          "updateHandler.autoCommit.openSearcher":false
        }
      }

      Name Components for the Config API

      The Config API always allows changing the configuration of any component by name. However, some configurations such as listener or initParams do not require a name in solrconfig.xml. In order to be able to update and delete of the same item in configoverlay.json, the name attribute becomes mandatory.

      How the Config API Works

      Every core watches the ZooKeeper directory for the configset being used with that core. In standalone mode, however, there is no watch (because ZooKeeper is not running). If there are multiple cores in the same node using the same configset, only one ZooKeeper watch is used.

      For instance, if the configset 'myconf' is used by a core, the node would watch /configs/myconf. Every write operation performed through the API would 'touch' the directory and all watchers are notified. Every core would check if the schema file, solrconfig.xml, or configoverlay.json has been modified by comparing the znode versions. If any have been modified, the core is reloaded.

      If params.json is modified, the params object is just updated without a core reload (see Request Parameters API for more information about params.json).

      Empty Command

      If an empty command is sent to the /config endpoint, the watch is triggered on all cores using this configset. For example:

      V1 API

      curl -X POST -H 'Content-type:application/json' -d '{}' http://localhost:8983/solr/techproducts/config

      V2 API

      curl -X POST -H 'Content-type:application/json' -d '{}' http://localhost:8983/api/collections/techproducts/config

      Directly editing any files without 'touching' the directory will not make it visible to all nodes.

      It is possible for components to watch for the configset 'touch' events by registering a listener using SolrCore#registerConfListener().

      Listening to Config Changes

      Any component can register a listener using:

      SolrCore#addConfListener(Runnable listener)

      to get notified for config changes. This is not very useful if the files modified result in core reloads (i.e., configoverlay.xml or the schema). Components can use this to reload the files they are interested in.