Class PingRequestHandler
- java.lang.Object
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- org.apache.solr.handler.RequestHandlerBase
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- org.apache.solr.handler.PingRequestHandler
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- All Implemented Interfaces:
AutoCloseable
,ApiSupport
,SolrInfoBean
,NestedRequestHandler
,SolrMetricProducer
,SolrRequestHandler
,PermissionNameProvider
,SolrCoreAware
public class PingRequestHandler extends RequestHandlerBase implements SolrCoreAware
Ping Request Handler for reporting SolrCore health to a Load Balancer.This handler is designed to be used as the endpoint for an HTTP Load-Balancer to use when checking the "health" or "up status" of a Solr server.
In its simplest form, the PingRequestHandler should be configured with some defaults indicating a request that should be executed. If the request succeeds, then the PingRequestHandler will respond back with a simple "OK" status. If the request fails, then the PingRequestHandler will respond back with the corresponding HTTP Error code. Clients (such as load balancers) can be configured to poll the PingRequestHandler monitoring for these types of responses (or for a simple connection failure) to know if there is a problem with the Solr server.
Note in case isShard=true, PingRequestHandler respond back with what the delegated handler returns (by default it's /select handler).
<requestHandler name="/admin/ping" class="solr.PingRequestHandler"> <lst name="invariants"> <str name="qt">/search</str><!-- handler to delegate to --> <str name="q">some test query</str> </lst> </requestHandler>
A more advanced option available, is to configure the handler with a "healthcheckFile" which can be used to enable/disable the PingRequestHandler.
<requestHandler name="/admin/ping" class="solr.PingRequestHandler"> <!-- relative paths are resolved against the data dir --> <str name="healthcheckFile">server-enabled.txt</str> <lst name="invariants"> <str name="qt">/search</str><!-- handler to delegate to --> <str name="q">some test query</str> </lst> </requestHandler>
- If the health check file exists, the handler will execute the delegated query and return status as described above.
- If the health check file does not exist, the handler will return an HTTP error even if the server is working fine and the delegated query would have succeeded
This health check file feature can be used as a way to indicate to some Load Balancers that the server should be "removed from rotation" for maintenance, or upgrades, or whatever reason you may wish.
The health check file may be created/deleted by any external system, or the PingRequestHandler itself can be used to create/delete the file by specifying an "action" param in a request:
http://.../ping?action=enable
- creates the health check file if it does not already existhttp://.../ping?action=disable
- deletes the health check file if it existshttp://.../ping?action=status
- returns a status code indicating if the healthcheck file exists ("enabled
") or not ("disabled
")
- Since:
- solr 1.3
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected static class
PingRequestHandler.ACTIONS
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Nested classes/interfaces inherited from class org.apache.solr.handler.RequestHandlerBase
RequestHandlerBase.HandlerMetrics
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Nested classes/interfaces inherited from interface org.apache.solr.security.PermissionNameProvider
PermissionNameProvider.Name
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Nested classes/interfaces inherited from interface org.apache.solr.core.SolrInfoBean
SolrInfoBean.Category, SolrInfoBean.Group
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Field Summary
Fields Modifier and Type Field Description static String
HEALTHCHECK_FILE_PARAM
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Fields inherited from class org.apache.solr.handler.RequestHandlerBase
aggregateNodeLevelMetricsEnabled, appends, defaults, httpCaching, initArgs, invariants, metrics, solrMetricsContext
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Fields inherited from interface org.apache.solr.security.PermissionNameProvider
ANY, NULL, values
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Fields inherited from interface org.apache.solr.request.SolrRequestHandler
TYPE
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Constructor Summary
Constructors Constructor Description PingRequestHandler()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description SolrInfoBean.Category
getCategory()
Category of this componentString
getDescription()
Simple one or two line descriptionPermissionNameProvider.Name
getPermissionName(AuthorizationContext request)
protected void
handleEnable(boolean enable)
protected void
handlePing(SolrQueryRequest req, SolrQueryResponse rsp)
void
handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp)
void
inform(SolrCore core)
void
init(org.apache.solr.common.util.NamedList<?> args)
Initializes theSolrRequestHandler
by creating threeSolrParams
named.boolean
isPingDisabled()
Returns true if the healthcheck flag-file is enabled but does not exist, otherwise (no file configured, or file configured and exists) returns false.Boolean
registerV2()
Whether this request handler must be made available at the /v2/ path-
Methods inherited from class org.apache.solr.handler.RequestHandlerBase
getApis, getInitArgs, getMetricsForThisRequest, getName, getPluginInfo, getRequestHandler, getSolrMetricsContext, getSolrParamsFromNamedList, getSubHandler, handleRequest, initializeMetrics, isInternalShardRequest, normalizeReceivedException, processErrorMetricsOnException, setPluginInfo
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.apache.solr.api.ApiSupport
getJerseyResources, registerV1
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Methods inherited from interface org.apache.solr.metrics.SolrMetricProducer
close
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Field Detail
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HEALTHCHECK_FILE_PARAM
public static final String HEALTHCHECK_FILE_PARAM
- See Also:
- Constant Field Values
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Method Detail
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getPermissionName
public PermissionNameProvider.Name getPermissionName(AuthorizationContext request)
- Specified by:
getPermissionName
in interfacePermissionNameProvider
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init
public void init(org.apache.solr.common.util.NamedList<?> args)
Description copied from class:RequestHandlerBase
Initializes theSolrRequestHandler
by creating threeSolrParams
named.table of parameters Name Description defaults Contains all of the named arguments contained within the list element named "defaults". appends Contains all of the named arguments contained within the list element named "appends". invariants Contains all of the named arguments contained within the list element named "invariants". Example:
<lst name="defaults"> <str name="echoParams">explicit</str> <str name="qf">text^0.5 features^1.0 name^1.2 sku^1.5 id^10.0</str> <str name="mm">2<-1 5<-2 6<90%</str> <str name="bq">incubationdate_dt:[* TO NOW/DAY-1MONTH]^2.2</str> </lst> <lst name="appends"> <str name="fq">inStock:true</str> </lst> <lst name="invariants"> <str name="facet.field">cat</str> <str name="facet.field">manu_exact</str> <str name="facet.query">price:[* TO 500]</str> <str name="facet.query">price:[500 TO *]</str> </lst>
- Specified by:
init
in interfaceSolrRequestHandler
- Overrides:
init
in classRequestHandlerBase
- Parameters:
args
- TheNamedList
to initialize from- See Also:
RequestHandlerBase.handleRequest(org.apache.solr.request.SolrQueryRequest, org.apache.solr.response.SolrQueryResponse)
,RequestHandlerBase.handleRequestBody(org.apache.solr.request.SolrQueryRequest, org.apache.solr.response.SolrQueryResponse)
,SolrPluginUtils.setDefaults(org.apache.solr.request.SolrQueryRequest, org.apache.solr.common.params.SolrParams, org.apache.solr.common.params.SolrParams, org.apache.solr.common.params.SolrParams)
,See also the example solrconfig.xml located in the Solr codebase (example/solr/conf).
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inform
public void inform(SolrCore core)
- Specified by:
inform
in interfaceSolrCoreAware
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isPingDisabled
public boolean isPingDisabled()
Returns true if the healthcheck flag-file is enabled but does not exist, otherwise (no file configured, or file configured and exists) returns false.
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handleRequestBody
public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp) throws Exception
- Specified by:
handleRequestBody
in classRequestHandlerBase
- Throws:
Exception
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handlePing
protected void handlePing(SolrQueryRequest req, SolrQueryResponse rsp) throws Exception
- Throws:
Exception
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handleEnable
protected void handleEnable(boolean enable) throws org.apache.solr.common.SolrException
- Throws:
org.apache.solr.common.SolrException
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getDescription
public String getDescription()
Description copied from interface:SolrInfoBean
Simple one or two line description- Specified by:
getDescription
in interfaceSolrInfoBean
- Specified by:
getDescription
in classRequestHandlerBase
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registerV2
public Boolean registerV2()
Description copied from interface:ApiSupport
Whether this request handler must be made available at the /v2/ path- Specified by:
registerV2
in interfaceApiSupport
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getCategory
public SolrInfoBean.Category getCategory()
Description copied from interface:SolrInfoBean
Category of this component- Specified by:
getCategory
in interfaceSolrInfoBean
- Overrides:
getCategory
in classRequestHandlerBase
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