Package com.yahoo.search.searchers

Class RateLimitingSearcher

java.lang.Object
com.yahoo.component.AbstractComponent
com.yahoo.component.chain.ChainedComponent
com.yahoo.processing.Processor
com.yahoo.search.Searcher
com.yahoo.search.searchers.RateLimitingSearcher
All Implemented Interfaces:
com.yahoo.component.Component, com.yahoo.component.Deconstructable, Comparable<com.yahoo.component.Component>
public class RateLimitingSearcher extends Searcher
A simple rate limiter.

This takes these query parameter arguments:

  • rate.id - (String) the id of the client from rate limiting perspective
  • rate.cost - (Double) the cost Double of this query. This is read after executing the query and hence can be set by downstream searchers inspecting the result to allow differencing the cost of various queries. Default is 1.
  • rate.quota - (Double) the cost per second a particular id is allowed to consume. By default this is across all nodes of the cluster (i.e, this is invariant with cluster size), set the config variable localRate to true to make this be rate per node.
  • rate.idDimension - (String) the name of the rate-id dimension used when logging metrics. If this is not specified, the metric will be logged without dimensions.
  • rate.dryRun - (Boolean) emit metrics on rejected requests but don't actually reject them

Whenever quota is exceeded for an id this searcher will reject queries from that id by returning a result containing a status 429 error.

If rate.id or rate.quota is not set in Query.properties this searcher will do nothing.

Metrics: This will emit the count metric requestsOverQuota with the dimension [rate.idDimension=rate.id] counting rejected requests.

Ordering: This searcher Provides rateLimiting

Author:
bratseth

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final com.yahoo.processing.request.CompoundName
    costKey
     
    static final com.yahoo.processing.request.CompoundName
    dryRunKey
     
    static final com.yahoo.processing.request.CompoundName
    idDimensionKey
     
    static final com.yahoo.processing.request.CompoundName
    idKey
     
    static final com.yahoo.processing.request.CompoundName
    quotaKey
     
    static final String
    RATE_LIMITING
    Constant containing the name this Provides - "rateLimiting", for ordering constraints

    Fields inherited from class com.yahoo.component.AbstractComponent

    isDeconstructable

  • Constructor Summary

    Constructors
    Constructor
    Description
    RateLimitingSearcher(RateLimitingConfig rateLimitingConfig, com.yahoo.cloud.config.ClusterInfoConfig clusterInfoConfig, com.yahoo.metrics.simple.MetricReceiver metric)
     
    RateLimitingSearcher(RateLimitingConfig rateLimitingConfig, com.yahoo.cloud.config.ClusterInfoConfig clusterInfoConfig, com.yahoo.metrics.simple.MetricReceiver metric, Clock clock)
    For testing - allows injection of a timer to avoid depending on the system clock

  • Method Summary

    Modifier and Type
    Method
    Description
    Result
    search(Query query, Execution execution)
    Override this to implement your searcher.

    Methods inherited from class com.yahoo.search.Searcher

    ensureFilled, fill, getLogger, process, toString

    Methods inherited from class com.yahoo.component.chain.ChainedComponent

    getAnnotatedDependencies, getDefaultAnnotatedDependencies, getDependencies, initDependencies

    Methods inherited from class com.yahoo.component.AbstractComponent

    clone, compareTo, deconstruct, getClassName, getId, getIdString, hasInitializedId, initId, isDeconstructable, setIsDeconstructable

    Methods inherited from class java.lang.Object

    equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Field Details

    • RATE_LIMITING

      public static final String RATE_LIMITING
      Constant containing the name this Provides - "rateLimiting", for ordering constraints
      See Also:

    • idKey

      public static final com.yahoo.processing.request.CompoundName idKey

    • costKey

      public static final com.yahoo.processing.request.CompoundName costKey

    • quotaKey

      public static final com.yahoo.processing.request.CompoundName quotaKey

    • idDimensionKey

      public static final com.yahoo.processing.request.CompoundName idDimensionKey

    • dryRunKey

      public static final com.yahoo.processing.request.CompoundName dryRunKey

  • Constructor Details

    • RateLimitingSearcher

      @Inject public RateLimitingSearcher(RateLimitingConfig rateLimitingConfig, com.yahoo.cloud.config.ClusterInfoConfig clusterInfoConfig, com.yahoo.metrics.simple.MetricReceiver metric)

    • RateLimitingSearcher

      public RateLimitingSearcher(RateLimitingConfig rateLimitingConfig, com.yahoo.cloud.config.ClusterInfoConfig clusterInfoConfig, com.yahoo.metrics.simple.MetricReceiver metric, Clock clock)
      For testing - allows injection of a timer to avoid depending on the system clock

  • Method Details

    • search

      public Result search(Query query, Execution execution)
      Description copied from class: Searcher
      Override this to implement your searcher.

      Searcher implementation subclasses will, depending on their type of logic, do one of the following:

      • Query processors: Access the query, then call execution.search and return the result
      • Result processors: Call execution.search to get the result, access it and return
      • Sources (which produces results): Create a result, add the desired hits and return it.
      • Federators (which forwards the search to multiple subchains): Call search on the desired subchains in parallel and get the results. Combine the results to one and return it.
      • Workflows: Call execution.search as many times as desired, using different queries. Eventually return a result.

      Hits come in two kinds - concrete hits are actual content of the kind requested by the user, meta hits are hits which provides information about the collection of hits, on the query, the service and so on.

      The query specifies a window into a larger result list that must be returned from the searcher through hits and offset; Searchers which returns list of hits in the top level in the result must return at least hits number of hits (or if impossible; all that are available), starting at the given offset. In addition, searchers are allowed to return any number of meta hits (although this number is expected to be low). For hits contained in nested hit groups, the concept of a window defined by hits and offset is not well defined and does not apply.

      Error handling in searchers:

      • Unexpected events: Throw any RuntimeException. This query will fail with the exception message, and the error will be logged
      • Expected events: Create (new Result(Query, ErrorMessage) or add result.setErrorIfNoOtherErrors(ErrorMessage) an error message to the Result.
      • Recoverable user errors: Add a FeedbackHit explaining the condition and how to correct it.
      Specified by:
      search in class Searcher
      Parameters:
      query - the query
      Returns:
      the result of making this query