io.druid.server

Class QueryLifecycle

java.lang.Object

io.druid.server.QueryLifecycle

public class QueryLifecycle
extends Object

Class that helps a Druid server (broker, historical, etc) manage the lifecycle of a query that it is handling. It ensures that a query goes through the following stages, in the proper order:

1. Initialization (initialize(Query))
2. Authorization (authorize(HttpServletRequest)
3. Execution (execute()
4. Logging (emitLogsAndMetrics(Throwable, String, long)

This object is not thread-safe.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	QueryLifecycle.QueryResponse

Constructor Summary

Constructors

Constructor and Description
QueryLifecycle(QueryToolChestWarehouse warehouse, QuerySegmentWalker texasRanger, GenericQueryMetricsFactory queryMetricsFactory, ServiceEmitter emitter, RequestLogger requestLogger, AuthorizerMapper authorizerMapper, long startMs, long startNs)

Method Summary

Modifier and Type	Method and Description
Access	authorize(AuthenticationResult authenticationResult) Authorize the query.
Access	authorize(javax.servlet.http.HttpServletRequest req) Authorize the query.
void	emitLogsAndMetrics(Throwable e, String remoteAddress, long bytesWritten) Emit logs and metrics for this query.
QueryLifecycle.QueryResponse	execute() Execute the query.
Query	getQuery()
void	initialize(Query baseQuery) Initializes this object to execute a specific query.
<T> Sequence<T>	runSimple(Query<T> query, AuthenticationResult authenticationResult, String remoteAddress) For callers where simplicity is desired over flexibility.

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryLifecycle

public QueryLifecycle(QueryToolChestWarehouse warehouse,
                      QuerySegmentWalker texasRanger,
                      GenericQueryMetricsFactory queryMetricsFactory,
                      ServiceEmitter emitter,
                      RequestLogger requestLogger,
                      AuthorizerMapper authorizerMapper,
                      long startMs,
                      long startNs)

Method Detail

runSimple

public <T> Sequence<T> runSimple(Query<T> query,
                                 AuthenticationResult authenticationResult,
                                 @Nullable
                                 String remoteAddress)

For callers where simplicity is desired over flexibility. This method does it all in one call. If the request is unauthorized, an IllegalStateException will be thrown. Logs and metrics are emitted when the Sequence is either fully iterated or throws an exception.

Parameters:

query - the query

authenticationResult - authentication result indicating identity of the requester

remoteAddress - remote address, for logging; or null if unknown

Returns:

results

initialize

public void initialize(Query baseQuery)

Initializes this object to execute a specific query. Does not actually execute the query.

Parameters:

baseQuery - the query

authorize

public Access authorize(AuthenticationResult authenticationResult)

Authorize the query. Will return an Access object denoting whether the query is authorized or not.

Parameters:

authenticationResult - authentication result indicating the identity of the requester

Returns:

authorization result

authorize

public Access authorize(javax.servlet.http.HttpServletRequest req)

Authorize the query. Will return an Access object denoting whether the query is authorized or not.

Parameters:

req - HTTP request object of the request. If provided, the auth-related fields in the HTTP request will be automatically set.

Returns:

authorization result

execute

public QueryLifecycle.QueryResponse execute()

Execute the query. Can only be called if the query has been authorized. Note that query logs and metrics will not be emitted automatically when the Sequence is fully iterated. It is the caller's responsibility to call emitLogsAndMetrics(Throwable, String, long) to emit logs and metrics.

Returns:

result sequence and response context

emitLogsAndMetrics

public void emitLogsAndMetrics(@Nullable
                               Throwable e,
                               @Nullable
                               String remoteAddress,
                               long bytesWritten)

Emit logs and metrics for this query.

Parameters:

e - exception that occurred while processing this query

remoteAddress - remote address, for logging; or null if unknown

bytesWritten - number of bytes written; will become a query/bytes metric if >= 0

getQuery

public Query getQuery()