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, user-managed clusters, and single-node installations. 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 configuration 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, defined implicitly by Solr, and 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 implicit request handlers linked above 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
        }}}}
}

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 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 Commits and Transaction Logs 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

Query Settings

See Caches and Query Warming 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

Query Circuit Breakers

See Circuit Breakers for more details

  • query.useCircuitBreakers

  • query.memoryCircuitBreakerThresholdPct

RequestDispatcher Settings

See RequestDispatcher 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-expressible

  • update-expressible

  • delete-expressible

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

Finally we will go ahead and remove the request handler via the delete-requesthandler command:

V1 API

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

V2 API

curl -X POST -H 'Content-type:application/json' -d '{
  "delete-requesthandler": "/myterms"
}' 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

updateRequestProcessorChain Elements

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

When using SolrCloud, every core watches the ZooKeeper directory for the configset being used with that core. If there are multiple cores in the same node using the same configset, only one ZooKeeper watch is used.

TIP

In a user-managed cluster or single-node installation, there is no watch (because ZooKeeper is not running).

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 of configuration 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.