org.apache.ambari.server.api.query.render

Class AlertSummaryRenderer

java.lang.Object

org.apache.ambari.server.api.query.render.BaseRenderer

org.apache.ambari.server.api.query.render.AlertSummaryRenderer

All Implemented Interfaces:

Renderer

Direct Known Subclasses:

AlertSummaryGroupedRenderer

public class AlertSummaryRenderer
extends BaseRenderer
implements Renderer

The AlertSummaryRenderer is used to format the results of queries to the alerts endpoint. Each item returned from the query represents an individual current alert which is then aggregated into a summary structure based on the alert state.

The finalized structure is:

 {
   "href" : "http://localhost:8080/api/v1/clusters/c1/alerts?format=summary",
   "alerts_summary" : {
     "CRITICAL" : {
       "count" : 3,
       "maintenance_count" : 1,
       "original_timestamp" : 1415372828182
     },
     "OK" : {
       "count" : 37,
       "maintenance_count" : 0,
       "original_timestamp" : 1415375364937
     },
     "UNKNOWN" : {
       "count" : 1,
       "maintenance_count" : 0,
       "original_timestamp" : 1415372632261
     },
     "WARN" : {
       "count" : 0,
       "maintenance_count" : 0,
       "original_timestamp" : 0
     }
   }
 }
 

The nature of a Renderer is that it manipulates the dataset returned by a query. In the case of alert data, the query could potentially return thousands of results if there are thousands of nodes in the cluster. This could present a performance issue that can only be addressed by altering the incoming query and modifying it to instruct the backend to return a JPA SUM instead of a collection of entities.

Constructor Summary

Constructors

Constructor and Description
AlertSummaryRenderer()

Method Summary

Modifier and Type	Method and Description
protected void	addRequiredAlertProperties(Set<String> properties) Adds properties to the backend request that are required by this renderer.
TreeNode<Set<String>>	finalizeProperties(TreeNode<QueryInfo> queryTree, boolean isCollection) Finalize which properties are requested by the query.
Result	finalizeResult(Result queryResult) Finalize the query results.
ResultPostProcessor	getResultPostProcessor(Request request) Obtain the associated post processor.

Methods inherited from class org.apache.ambari.server.api.query.render.BaseRenderer

addKeys, addPrimaryKey, addSubResources, copyPropertiesToResult, ensureRequiredProperties, getSchema, init, isRequestWithNoProperties, populateSubResourceDefaults, requiresPropertyProviderInput

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.ambari.server.api.query.render.Renderer

init, requiresPropertyProviderInput

Constructor Detail

AlertSummaryRenderer

public AlertSummaryRenderer()

Method Detail

finalizeProperties

public TreeNode<Set<String>> finalizeProperties(TreeNode<QueryInfo> queryTree,
                                                boolean isCollection)

Finalize which properties are requested by the query. This is called once per user query regardless of how many sub-queries the original query is decomposed into.

Specified by:

finalizeProperties in interface Renderer

Parameters:

queryTree - tree of query information. Contains query information for the root query and all sub-queries (children)

isCollection - whether the query is a collection

Returns:

tree of sets of string properties for each query including any sub-queries

getResultPostProcessor

public ResultPostProcessor getResultPostProcessor(Request request)

Obtain the associated post processor. Post Processors existed prior to renderer's to allow the native result to be augmented before returning it to the user. This functionality should be merged into the renderer.

Specified by:

getResultPostProcessor in interface Renderer

Parameters:

request - original request

Returns:

associated post processor

finalizeResult

public Result finalizeResult(Result queryResult)

Finalize the query results.

This will iterate over all of the nodes in the result tree and combine their AlertResourceProvider.ALERT_STATE into a single summary structure.

Specified by:

finalizeResult in interface Renderer

Parameters:

queryResult - result of query in native (default) format

Returns:

result in the format dictated by the renderer

addRequiredAlertProperties

protected void addRequiredAlertProperties(Set<String> properties)

Adds properties to the backend request that are required by this renderer. This method currently adds AlertResourceProvider.ALERT_STATE and AlertResourceProvider.ALERT_ORIGINAL_TIMESTAMP.

Parameters:

properties - the properties collection to add to.