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com.twitter

finagle

package finagle

Finagle is an extensible RPC system.

Services are represented by class com.twitter.finagle.Service. Clients make use of com.twitter.finagle.Service objects while servers implement them.

Finagle contains a number of protocol implementations; each of these implement Client and/or com.twitter.finagle.Server. For example, Finagle's HTTP implementation, com.twitter.finagle.Http (in package finagle-http), exposes both.

Thus a simple HTTP server is built like this:

import com.twitter.finagle.{Http, Service}
import com.twitter.finagle.http.{Request, Response}
import com.twitter.util.{Await, Future}

val service = new Service[Request, Response] {
  def apply(req: Request): Future[Response] =
    Future.value(Response())
}
val server = Http.server.serve(":8080", service)
Await.ready(server)

We first define a service to which requests are dispatched. In this case, the service returns immediately with a HTTP 200 OK response, and with no content.

This service is then served via the Http protocol on TCP port 8080. Finally we wait for the server to stop serving.

We can now query our web server:

% curl -D - localhost:8080
HTTP/1.1 200 OK

Building an HTTP client is also simple. (Note that type annotations are added for illustration.)

import com.twitter.finagle.{Http, Service}
import com.twitter.finagle.http.{Request, Response}
import com.twitter.util.{Future, Return, Throw}

val client: Service[Request, Response] = Http.client.newService("localhost:8080")
val f: Future[Response] = client(Request()).respond {
  case Return(rep) =>
    printf("Got HTTP response %s\n", rep)
  case Throw(exc) =>
    printf("Got error %s\n", exc)
}

Http.client.newService("localhost:8080") constructs a new com.twitter.finagle.Service instance connected to localhost TCP port 8080. We then issue a HTTP/1.1 GET request to URI "/". The service returns a com.twitter.util.Future representing the result of the operation. We listen to this future, printing an appropriate message when the response arrives.

The Finagle homepage contains useful documentation and resources for using Finagle.

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Type Members

  1. abstract class AbstractCodec [Req, Rep] extends Codec[Req, Rep]

    An abstract class version of the above for java compatibility.

  2. abstract class AbstractNamer extends Namer

    Abstract Namer class for Java compatibility.

  3. abstract class AbstractResolver extends Resolver

    An abstract class version of Resolver for java compatibility.

  4. sealed trait Addr extends AnyRef

    An address identifies the location of an object--it is a bound name.

    An address identifies the location of an object--it is a bound name. An object may be replicated, and thus bound to multiple physical locations (see com.twitter.finagle.Address).

    See also

    The user guide for further details.

  5. sealed trait Address extends AnyRef

    An Address represents the physical location of a single host or endpoint.

    An Address represents the physical location of a single host or endpoint. It also includes Addr.Metadata (typically set by Namers and Resolvers) that provides additional configuration to client stacks.

    Note that a bound Addr contains a set of Addresses and Addr.Metadata that pertains to the entire set.

  6. trait Announcement extends Closable
  7. trait Announcer extends AnyRef
  8. class AnnouncerForumInvalid extends Exception

    Indicates that a forum string passed to an com.twitter.finagle.Announcer was invalid according to the forum grammar [1].

    Indicates that a forum string passed to an com.twitter.finagle.Announcer was invalid according to the forum grammar [1].

    [1] https://twitter.github.io/finagle/guide/Names.html

  9. class AnnouncerNotFoundException extends Exception

    Indicates that an com.twitter.finagle.Announcer was not found for the given scheme.

    Indicates that an com.twitter.finagle.Announcer was not found for the given scheme.

    Announcers are discovered via Finagle's com.twitter.finagle.util.LoadService mechanism. These exceptions typically suggest that there are no libraries on the classpath that define an Announcer for the given scheme.

  10. class ApiException extends Exception

    A base class for exceptions encountered on account of incorrect API usage.

  11. trait CanStackFrom [-From, To] extends AnyRef

    A typeclass for "stackable" items.

    A typeclass for "stackable" items. This is used by the StackBuilder to provide a convenient interface for constructing Stacks.

    Annotations
    @implicitNotFound( "${From} is not Stackable to ${To}" )
  12. class CancelledConnectionException extends RequestException with HasLogLevel

    A Future is satisfied with this exception when the process of establishing a session is interrupted.

    A Future is satisfied with this exception when the process of establishing a session is interrupted. Sessions are not preemptively established in Finagle, rather requests are taxed with session establishment when necessary. For example, this exception can occur if a request is interrupted while waiting for an available session or if an interrupt is propagated from a Finagle server during session establishment.

    See also

    The user guide for additional details.

    com.twitter.finagle.CancelledRequestException

  13. class CancelledRequestException extends RequestException with HasLogLevel

    Indicates that a request was cancelled.

    Indicates that a request was cancelled. Cancellation is propagated between a Finagle server and a client intra-process when the server is interrupted by an upstream service. In such cases, the pending Future is interrupted with this exception. The client will cancel its pending request which will by default propagate an interrupt to its downstream, and so on. This is done to conserve resources.

    See also

    The user guide for additional details.

  14. class ChannelBufferUsageException extends Exception

    Indicates that an error occurred on account of incorrect usage of a org.jboss.netty.buffer.ChannelBuffer.

    Indicates that an error occurred on account of incorrect usage of a org.jboss.netty.buffer.ChannelBuffer.

    TODO: Probably remove this exception class once we migrate away from Netty usage in public APIs.

  15. class ChannelClosedException extends ChannelException with NoStackTrace

    Indicates that a given channel was closed, for instance if the connection was reset by a peer or a proxy.

  16. class ChannelException extends Exception with SourcedException with HasLogLevel

    An exception encountered within the context of a given socket channel.

  17. case class ChannelWriteException (underlying: Throwable) extends ChannelException with WriteException with NoStackTrace with Product with Serializable

    Default implementation for WriteException that wraps an underlying exception.

  18. trait Client [Req, Rep] extends AnyRef

    RPC clients with Req-typed requests and Rep typed replies.

    RPC clients with Req-typed requests and Rep typed replies. RPC destinations are represented by names. Names are bound for each request.

    Clients are implemented by the various protocol packages in finagle, for example com.twitter.finagle.Http:

    object Http extends Client[HttpRequest, HttpResponse] ...
    
    val service: Service[HttpRequest, HttpResponse] =
      Http.newService("google.com:80")
  19. case class ClientCodecConfig (serviceName: String) extends Product with Serializable

    Clients

  20. trait ClientConnection extends Closable

    Information about a client, passed to a Service factory for each new connection.

  21. trait Codec [Req, Rep] extends AnyRef

    Codecs provide protocol encoding and decoding via netty pipelines as well as a standard filter stack that is applied to services from this codec.

  22. trait CodecFactory [Req, Rep] extends AnyRef

    A combined codec factory provides both client and server codec factories in one (when available).

  23. class ConnectionFailedException extends ChannelException with NoStackTrace

    Indicates that the client failed to establish a connection.

    Indicates that the client failed to establish a connection. Typically this class will be extended to provide additional information relevant to a particular category of connection failure.

  24. case class ConnectionRefusedException (remoteAddress: SocketAddress) extends ChannelException with Product with Serializable

    Indicates that connecting to a given remoteAddress was refused.

  25. case class Dentry (prefix: Prefix, dst: NameTree[Path]) extends Product with Serializable

    Trait Dentry describes a delegation table entry.

    Trait Dentry describes a delegation table entry. prefix describes the paths that the entry applies to. dst describes the resulting tree for this prefix on lookup.

  26. class DroppedWriteException extends TransportException

    Indicates that a com.twitter.finagle.transport.Transport write associated with the request was dropped by the transport (usually to respect backpressure).

  27. case class Dtab (dentries0: IndexedSeq[Dentry]) extends IndexedSeq[Dentry] with Product with Serializable

    A Dtab--short for delegation table--comprises a sequence of delegation rules.

    A Dtab--short for delegation table--comprises a sequence of delegation rules. Together, these describe how to bind a com.twitter.finagle.Path to a set of com.twitter.finagle.Addr. com.twitter.finagle.naming.DefaultInterpreter implements the default binding stategy.

    See also

    The user guide for further details.

  28. final class DtabBuilder extends Builder[Dentry, Dtab]
  29. class FactoryToService [Req, Rep] extends Service[Req, Rep]

    Turns a com.twitter.finagle.ServiceFactory into a com.twitter.finagle.Service which acquires a new service for each request.

  30. class FailedFastException extends RequestException with WriteException with HasLogLevel with FailureFlags[FailedFastException]

    Used by com.twitter.finagle.service.FailFastFactory to indicate that a request failed because all hosts in the cluster to which the client is connected have been marked as failed.

    Used by com.twitter.finagle.service.FailFastFactory to indicate that a request failed because all hosts in the cluster to which the client is connected have been marked as failed. See com.twitter.finagle.service.FailFastFactory for details on this behavior.

    See also

    The user guide for additional details.

  31. final class Failure extends Exception with NoStackTrace with HasLogLevel with FailureFlags[Failure]

    Base exception for all Finagle originated failures.

    Base exception for all Finagle originated failures. These are Exceptions, but with additional sources and flags. Sources describe the origins of the failure to aid in debugging and flags mark attributes of the Failure (e.g. Restartable).

  32. abstract class Filter [-ReqIn, +RepOut, +ReqOut, -RepIn] extends (ReqIn, Service[ReqOut, RepIn]) ⇒ Future[RepOut]

    A Filter acts as a decorator/transformer of a service.

    A Filter acts as a decorator/transformer of a service. It may apply transformations to the input and output of that service:

              (*  MyService  *)
    [ReqIn -> (ReqOut -> RepIn) -> RepOut]

    For example, you may have a service that takes Strings and parses them as Ints. If you want to expose this as a Network Service via Thrift, it is nice to isolate the protocol handling from the business rules. Hence you might have a Filter that converts back and forth between Thrift structs. Again, your service deals with plain objects:

    [ThriftIn -> (String  ->  Int) -> ThriftOut]

    Thus, a Filter[A, B, C, D] converts a Service[C, D] to a Service[A, B]. In other words, it converts a Service[ReqOut, RepIn] to a Service[ReqIn, RepOut].

    See also

    The user guide for details and examples.

  33. class GlobalRequestTimeoutException extends RequestTimeoutException

    Indicates that a request timed out, where "request" comprises a full RPC from the perspective of the application.

    Indicates that a request timed out, where "request" comprises a full RPC from the perspective of the application. For instance, multiple retried Finagle-level requests could constitute the single request that this exception pertains to.

  34. trait HasRemoteInfo extends Exception

    A trait for exceptions that contain remote information: the downstream address/client id, upstream address/client id (if applicable), and trace id of the request.

    A trait for exceptions that contain remote information: the downstream address/client id, upstream address/client id (if applicable), and trace id of the request. RemoteInfo.NotAvailable is used if no remote information has been set.

  35. trait HttpRichClient extends AnyRef

    A rich HTTP/1.1 client with a *very* basic URL fetcher.

    A rich HTTP/1.1 client with a *very* basic URL fetcher. (It does not handle redirects, does not have a cookie jar, etc.)

  36. class InconsistentStateException extends ChannelException

    Indicates that some client state was inconsistent with the observed state of some server.

    Indicates that some client state was inconsistent with the observed state of some server. For example, the client could receive a channel-connection event from a proxy when there is no outstanding connect request.

  37. class IndividualRequestTimeoutException extends RequestTimeoutException

    Indicates that a single Finagle-level request timed out.

    Indicates that a single Finagle-level request timed out. In contrast to com.twitter.finagle.RequestTimeoutException, an "individual request" could be a single request-retry performed as a constituent of an application-level RPC.

  38. trait ListeningServer extends Closable with Awaitable[Unit] with Group[SocketAddress]

    Trait ListeningServer represents a bound and listening server.

    Trait ListeningServer represents a bound and listening server. Closing a server instance unbinds the port and relinquishes resources that are associated with the server.

  39. trait MemcachedRichClient extends AnyRef

    Factory methods to build a finagle-memcached client.

  40. class MultipleAnnouncersPerSchemeException extends Exception with NoStackTrace

    Indicates that multiple Announcers were discovered for given scheme.

    Indicates that multiple Announcers were discovered for given scheme.

    Announcers are discovered via Finagle's com.twitter.finagle.util.LoadService mechanism. These exceptions typically suggest that there are multiple libraries on the classpath with conflicting scheme definitions.

  41. class MultipleResolversPerSchemeException extends Exception with NoStackTrace

    Indicates that multiple Resolvers were discovered for given scheme.

    Indicates that multiple Resolvers were discovered for given scheme.

    Resolvers are discovered via Finagle's com.twitter.finagle.util.LoadService mechanism. These exceptions typically suggest that there are multiple libraries on the classpath with conflicting scheme definitions.

  42. trait MysqlRichClient extends AnyRef

    Supplements a com.twitter.finagle.Client with convenient builder methods for constructing a mysql client.

  43. sealed trait Name extends AnyRef

    Names identify network locations.

    Names identify network locations. They come in two varieties:

    1. Bound names are concrete. They represent a changeable list of network endpoints (represented by Addrs).

    2. Path names are unbound paths, representing an abstract location which must be resolved by some context, usually the Dtab.

    In practice, clients use a com.twitter.finagle.Resolver to resolve a destination name string into a Name. This is achieved by passing a destination name into methods such as ClientBuilder.dest or the newClient method of the appropriate protocol object (e.g. Http.newClient(/s/org/servicename)). These APIs use Resolver under the hood to resolve the destination names into the Name representation of the appropriate cluster.

    As names are bound, a Namer may elect to bind only a Name prefix, leaving an unbound residual name to be processed by a downstream Namer.

    See also

    The user guide for further details.

  44. sealed trait NameTree [+T] extends AnyRef

    Name trees represent a composite T-typed name whose interpretation is subject to evaluation rules.

    Name trees represent a composite T-typed name whose interpretation is subject to evaluation rules. Typically, a Namer is used to provide evaluation context for these trees.

    • com.twitter.finagle.NameTree.Union nodes represent the union of several trees; a destination is reached by load-balancing over the sub-trees.
    • Alt nodes represent a fail-over relationship between several trees; the first successful tree is picked as the destination. When the tree-list is empty, Alt-nodes evaluate to Empty.
    • A Leaf represents a T-typed leaf node;
    • A Neg represents a negative location; no destination exists here.
    • Finally, Empty trees represent an empty location: it exists but is uninhabited at this time.
  45. abstract class Namer extends AnyRef

    A namer is a context in which a NameTree is bound.

    A namer is a context in which a NameTree is bound. The context is provided by the lookup method, which translates Paths into NameTrees. Namers may represent external processes, for example lookups through DNS or to ZooKeeper, and thus lookup results are represented by a Activity.

  46. class NoBrokersAvailableException extends RequestException with SourcedException

    Indicates that a request failed because no servers were available.

    Indicates that a request failed because no servers were available. The Finagle client's internal load balancer was empty. This typically occurs under one of the following conditions:

    - The cluster is actually down. No servers are available. - A service discovery failure. This can be due to a number of causes, such as the client being constructed with an invalid cluster destination name [1] or a failure in the service discovery system (e.g. DNS, ZooKeeper).

    A good way to diagnose NoBrokersAvailableExceptions is to reach out to the owners of the service to which the client is attempting to connect and verify that the service is operational. If so, then investigate the service discovery mechanism that the client is using (e.g. the com.twitter.finagle.Resolver that is it configured to use and the system backing it).

    [1] http://twitter.github.io/finagle/guide/Names.html

  47. class NotServableException extends RequestException

    Indicates that the request was not servable, according to some policy.

    Indicates that the request was not servable, according to some policy. See com.twitter.finagle.service.OptionallyServableFilter as an example.

  48. class NotShardableException extends NotServableException

    Indicates that the client failed to distribute a given request according to some sharding strategy.

    Indicates that the client failed to distribute a given request according to some sharding strategy. See com.twitter.finagle.service.ShardingService for details on this behavior.

  49. case class Path (elems: Buf*) extends Product with Serializable

    A Path comprises a sequence of byte buffers naming a hierarchically-addressed object.

    A Path comprises a sequence of byte buffers naming a hierarchically-addressed object.

    See also

    The user guide for further details.

  50. trait ProxyAnnouncement extends Announcement with Proxy
  51. class ReadTimedOutException extends ChannelException

    Indicates that a read from a given remoteAddress timed out.

  52. trait RedisRichClient extends AnyRef
  53. case class RefusedByRateLimiter () extends ChannelException with Product with Serializable

    Indicates that requests were failed by a rate-limiter.

    Indicates that requests were failed by a rate-limiter. See com.twitter.finagle.service.RateLimitingFilter for details.

  54. class RequestException extends Exception with NoStackTrace with SourcedException

    A base class for request failures.

    A base class for request failures. Indicates that some failure occurred before a request could be successfully serviced.

  55. class RequestTimeoutException extends RequestException with TimeoutException

    Indicates that a request timed out.

    Indicates that a request timed out. See com.twitter.finagle.IndividualRequestTimeoutException and com.twitter.finagle.GlobalRequestTimeoutException for details on the different request granularities that this exception class can pertain to.

  56. trait Resolver extends AnyRef

    A resolver binds a name, represented by a string, to a variable address.

    A resolver binds a name, represented by a string, to a variable address. Resolvers have an associated scheme which is used for lookup so that names may be resolved in a global context.

    These are loaded by Finagle through the service loading mechanism. Thus, in order to implement a new resolver, a class implementing Resolver with a 0-arg constructor must be registered in a file named META-INF/services/com.twitter.finagle.Resolver included in the classpath; see Oracle's ServiceLoader documentation for further details.

  57. class ResolverAddressInvalid extends Exception

    Indicates that a destination name string passed to a com.twitter.finagle.Resolver was invalid according to the destination name grammar [1].

    Indicates that a destination name string passed to a com.twitter.finagle.Resolver was invalid according to the destination name grammar [1].

    [1] https://twitter.github.io/finagle/guide/Names.html

  58. class ResolverNotFoundException extends Exception

    Indicates that a com.twitter.finagle.Resolver was not found for the given scheme.

    Indicates that a com.twitter.finagle.Resolver was not found for the given scheme.

    Resolvers are discovered via Finagle's com.twitter.finagle.util.LoadService mechanism. These exceptions typically suggest that there are no libraries on the classpath that define a Resolver for the given scheme.

  59. trait Server [Req, Rep] extends AnyRef

    Servers implement RPC servers with Req-typed requests and Rep-typed responses.

    Servers implement RPC servers with Req-typed requests and Rep-typed responses. Servers dispatch requests to a com.twitter.finagle.Service or com.twitter.finagle.ServiceFactory provided through serve.

    Servers are implemented by the various protocol packages in finagle, for example com.twitter.finagle.Http:

    object Http extends Server[HttpRequest, HttpResponse] ...
    
    val server = Http.serve(":*", new Service[HttpRequest, HttpResponse] {
      def apply(req: HttpRequest): Future[HttpResponse] = ...
    })

    Will bind to an ephemeral port (":*") and dispatch request to server.boundAddress to the provided com.twitter.finagle.Service instance.

    The serve method has two variants: one for instances of Service, and another for ServiceFactory. The ServiceFactory variants are used for protocols in which connection state is significant: a new Service is requested from the ServiceFactory for each new connection, and requests on that connection are dispatched to the supplied service. The service is also closed when the client disconnects or the connection is otherwise terminated.

  60. case class ServerCodecConfig (serviceName: String, boundAddress: SocketAddress) extends Product with Serializable

    Servers

  61. abstract class Service [-Req, +Rep] extends (Req) ⇒ Future[Rep] with Closable

    A Service is an asynchronous function from a Request to a Future[Response].

    A Service is an asynchronous function from a Request to a Future[Response].

    It is the basic unit of an RPC interface.

    See also

    Service.mk for a convenient way to create new instances.

    The user guide for details and examples.

  62. class ServiceClosedException extends Exception with ServiceException

    Indicates that a request was applied to a com.twitter.finagle.Service that is closed (i.e.

    Indicates that a request was applied to a com.twitter.finagle.Service that is closed (i.e. the connection is closed).

  63. trait ServiceException extends Exception with SourcedException

    A trait for exceptions related to a com.twitter.finagle.Service.

  64. abstract class ServiceFactory [-Req, +Rep] extends (ClientConnection) ⇒ Future[Service[Req, Rep]] with Closable
  65. abstract class ServiceFactoryProxy [-Req, +Rep] extends ServiceFactory[Req, Rep] with Proxy

    A ServiceFactory that proxies all calls to another ServiceFactory.

    A ServiceFactory that proxies all calls to another ServiceFactory. This can be useful if you want to modify an existing ServiceFactory.

  66. trait ServiceFactoryWrapper extends AnyRef

    A ServiceFactoryWrapper adds behavior to an underlying ServiceFactory.

  67. trait ServiceNamer [Req, Rep] extends Namer

    Base-trait for Namers that bind to a local Service.

    Base-trait for Namers that bind to a local Service.

    Implementers with a 0-argument constructor may be named and auto-loaded with /$/pkg.cls syntax.

    Note that this can't actually be accomplished in a type-safe manner since the naming step obscures the service's type to observers.

  68. class ServiceNotAvailableException extends Exception with ServiceException

    Indicates that a request was applied to a com.twitter.finagle.Service that is unavailable.

    Indicates that a request was applied to a com.twitter.finagle.Service that is unavailable. This constitutes a fail-stop condition.

  69. abstract class ServiceProxy [-Req, +Rep] extends Service[Req, Rep] with Proxy

    A simple proxy Service that forwards all calls to another Service.

    A simple proxy Service that forwards all calls to another Service. This is useful if you want to wrap-but-modify an existing service.

  70. class ServiceTimeoutException extends Exception with WriteException with ServiceException with TimeoutException with NoStackTrace

    Indicates that the connection was not established within the timeouts.

    Indicates that the connection was not established within the timeouts. This type of exception should generally be safe to retry.

  71. class ShardNotAvailableException extends NotServableException

    Indicates that the shard to which a request was assigned was not available.

    Indicates that the shard to which a request was assigned was not available. See com.twitter.finagle.service.ShardingService for details on this behavior.

  72. abstract class SimpleFilter [Req, Rep] extends Filter[Req, Rep, Req, Rep]

    A Filter where the request and reply types are the same.

  73. trait SourcedException extends Exception with HasRemoteInfo

    A trait for exceptions that have a source.

    A trait for exceptions that have a source. The name of the source is specified as a serviceName. The "unspecified" value is used if no serviceName is provided by the implementation.

  74. case class SslHandshakeException (underlying: Throwable, remoteAddress: SocketAddress) extends ChannelException with Product with Serializable

    Indicates that an error occurred while an SSL handshake was being performed with a server at a given remoteAddress.

  75. case class SslHostVerificationException (principal: String) extends ChannelException with Product with Serializable

    Indicates that the certificate for a given session was invalidated.

  76. sealed trait Stack [T] extends AnyRef

    Stacks represent stackable elements of type T.

    Stacks represent stackable elements of type T. It is assumed that T-typed elements can be stacked in some meaningful way; examples are functions (function composition) Filters (chaining), and ServiceFactories (through transformers). T-typed values are also meant to compose: the stack itself materializes into a T-typed value.

    Stacks are persistent, allowing for nondestructive transformations; they are designed to represent 'template' stacks which can be configured in various ways before materializing the stack itself.

    Note: Stacks are advanced and sometimes subtle. For expert use only!

  77. class StackBuilder [T] extends AnyRef

    StackBuilders are imperative-style builders for Stacks.

    StackBuilders are imperative-style builders for Stacks. It maintains a stack onto which new elements can be pushed (defining a new stack).

    See also

    stack.nilStack for starting construction of an empty stack for ServiceFactorys.

  78. trait Stackable [T] extends Head

    Produce a stack from a T-typed element.

  79. sealed trait Status extends AnyRef

    Status tells the condition of a networked endpoint.

    Status tells the condition of a networked endpoint. They are used to indicate the health of Service, ServiceFactory, and of transport.Transport.

    Object Status$ contains the status definitions.

  80. class StreamClosedException extends ChannelException with NoStackTrace

    Indicates that a given stream was closed, for instance if the stream was reset by a peer or a proxy.

  81. trait ThriftRichClient extends AnyRef

    A mixin trait to provide a rich Thrift client API.

  82. trait ThriftRichServer extends AnyRef

    A mixin trait to provide a rich Thrift server API.

  83. trait TimeoutException extends Exception with SourcedException with HasLogLevel

    Indicates that an operation exceeded some timeout duration before completing.

    Indicates that an operation exceeded some timeout duration before completing. Differs from com.twitter.util.TimeoutException in that this trait doesn't extend java.util.concurrent.TimeoutException, provides more context in its error message (e.g. the source and timeout value), and is only used within the confines of Finagle.

  84. class TooManyConcurrentRequestsException extends ApiException

    Indicates that the client has issued more concurrent requests than are allowable, where "allowable" is typically determined based on some configurable maximum.

  85. class TooManyWaitersException extends RequestException with HasLogLevel

    Used by com.twitter.finagle.pool.WatermarkPool to indicate that a request failed because too many requests are already waiting for a connection to become available from a client's connection pool.

  86. class TransportException extends Exception with SourcedException

    A base class for exceptions encountered in the context of a com.twitter.finagle.transport.Transport.

  87. case class UnknownChannelException (underlying: Throwable, remoteAddress: SocketAddress) extends ChannelException with Product with Serializable

    A catch-all exception class for uncategorized ChannelExceptions.

  88. trait WriteException extends Exception with SourcedException

    Marker trait to indicate there was an exception before writing any of the request.

    Marker trait to indicate there was an exception before writing any of the request. These exceptions should generally be retryable.

    See also

    com.twitter.finagle.service.RetryPolicy.WriteExceptionsOnly

    com.twitter.finagle.service.RetryPolicy.RetryableWriteException

  89. class WriteTimedOutException extends ChannelException

    Indicates that a write to a given remoteAddress timed out.

  90. class Deadline extends finagle.context.Deadline
    Annotations
    @deprecated
    Deprecated

    (Since version 2016-08-22) Use com.twitter.finagle.context.Deadline instead

  91. trait Group [T] extends AnyRef

    A group is a dynamic set of T-typed values.

    A group is a dynamic set of T-typed values. It is used to represent dynamic hosts and operations over such lists. Its flexibility is derived from the ability to map, creating derived groups. The map operation ensures that each element is mapped over exactly once, allowing side-effecting operations to rely on this to implement safe semantics.

    Note: querying groups is nonblocking, which means that derived groups are effectively eventually consistent.

    Note: Ts must be hashable, defining hashCode and equals to ensure that maps have exactly-once semantics.

    Note: Groups are invariant because Scala's Sets are. In the case of sets, this is an implementation artifact, and is unfortunate, but it's better to keep things simpler and consistent.

    Annotations
    @deprecated
    Deprecated

    (Since version 6.7.x) Use com.twitter.finagle.Name to represent clusters instead

  92. case class LabelledGroup [T](underlying: Group[T], name: String) extends Group[T] with Product with Serializable

    A mixin trait to assign a name to the group.

    A mixin trait to assign a name to the group. This is used to assign labels to groups that ascribe meaning to them.

    Annotations
    @deprecated
    Deprecated

    (Since version 6.7.x) Use com.twitter.finagle.Name to represent clusters instead

  93. trait MutableGroup [T] extends Group[T]
    Annotations
    @deprecated
    Deprecated

    (Since version 6.7.x) Use com.twitter.finagle.Name to represent clusters instead

Value Members

  1. object Addr

    Note: There is a Java-friendly API for this object: com.twitter.finagle.Addrs.

  2. object Address
  3. object Addresses

    A Java adaptation of the com.twitter.finagle.Address companion object.

  4. object Addrs

    A Java adaptation of the com.twitter.finagle.Addr companion object.

  5. object Announcer
  6. object BackupRequestLost extends Exception with NoStackTrace with HasLogLevel

    An exception that is raised on requests that are discarded because their corresponding backup requests succeeded first.

    An exception that is raised on requests that are discarded because their corresponding backup requests succeeded first. See com.twitter.finagle.exp.BackupRequestFilter for details.

  7. object CanStackFrom
  8. object ChannelException extends Serializable
  9. object ClientConnection
  10. object Codec
  11. object Dentry extends Serializable
  12. object Dtab extends Serializable

    Object Dtab manages 'base' and 'local' Dtabs.

  13. object FactoryToService
  14. object FailResolver extends Resolver
  15. object Failure extends Serializable
  16. object FailureFlags extends Serializable

    FailureFlags may be applied to any Failure/Exception encountered during the handling of a request.

  17. object Filter
  18. object FixedInetResolver

    InetResolver that caches all successful DNS lookups indefinitely and does not poll for updates.

    InetResolver that caches all successful DNS lookups indefinitely and does not poll for updates.

    Clients should only use this in scenarios where host -> IP map changes do not occur.

  19. object Group
  20. object Http extends Client[Request, Response] with HttpRichClient with Server[Request, Response]

    HTTP/1.1 protocol support, including client and server.

  21. object InetResolver

    Resolver for inet scheme.

  22. object Kestrel
  23. object Memcached extends Client[Command, Response] with Server[Command, Response]

    Stack based Memcached client.

    Stack based Memcached client.

    For example, a default client can be built through:

    Examples:
    1. val client =
        Memcached.client
          .withEjectFailedHost(true)
          .withTransport.connectTimeout(100.milliseconds))
          .withRequestTimeout(10.seconds)
          .withSession.acquisitionTimeout(20.seconds)
          .newRichClient(dest, "memcached_client")
    2. ,
    3. val client = Memcached.newRichClient(dest)

      If you want to provide more finely tuned configurations:

  24. object Mux extends Client[Request, Response] with Server[Request, Response]

    A client and server for the mux protocol described in com.twitter.finagle.mux.

  25. object MySqlClientTracingFilter
  26. object Mysql extends Client[Request, Result] with MysqlRichClient

    Example:
    1. val client = Mysql.client
        .withCredentials("", "")
        .withDatabase("")
        .newRichClient("inet!localhost:3306")
  27. object Name
  28. object NameTree

    The NameTree object comprises NameTree types as well as binding and evaluation routines.

  29. object Namer
  30. object NegResolver extends Resolver
  31. object NilResolver extends Resolver
  32. object NullServer extends ListeningServer with CloseAwaitably

    An empty ListeningServer that can be used as a placeholder.

    An empty ListeningServer that can be used as a placeholder. For example:

    @volatile var server = NullServer
    def main() { server = Http.serve(...) }
    def exit() { server.close() }
  33. object Path extends Serializable
  34. object Redis extends Client[Command, Reply] with RedisRichClient
  35. object Resolver extends BaseResolver

    The default Resolver used by Finagle.

    The default Resolver used by Finagle.

    See also

    Resolvers for Java support.

  36. object Resolvers

    Java APIs for Resolver.

  37. object Service
  38. object ServiceFactory
  39. object ServiceFactoryWrapper
  40. object SourcedException extends Serializable
  41. object Stack

    See also

    stack.nilStack for starting construction of an empty stack for ServiceFactorys.

  42. object Status

    Define valid Status! values.

    Define valid Status! values. They are, in order from most to least healthy:

    • Open
    • Busy
    • Closed

    (An scala.math.Ordering is defined in these terms.)

  43. object Thrift extends Client[ThriftClientRequest, Array[Byte]] with Server[Array[Byte], Array[Byte]]

    Client and server for Apache Thrift.

    Client and server for Apache Thrift. Thrift implements Thrift framed transport and binary protocol by default, though custom protocol factories (i.e. wire encoding) may be injected with withProtocolFactory. The client, Client[ThriftClientRequest, Array[Byte]] provides direct access to the thrift transport, but we recommend using code generation through either Scrooge or a fork of the Apache generator. A rich API is provided to support interfaces generated with either of these code generators.

    The client and server uses the standard thrift protocols, with support for both framed and buffered transports. Finagle attempts to upgrade the protocol in order to ship an extra envelope carrying additional request metadata, containing, among other things, request IDs for Finagle's RPC tracing facilities.

    The negotiation is simple: on connection establishment, an improbably-named method is dispatched on the server. If that method isn't found, we are dealing with a legacy thrift server, and the standard protocol is used. If the remote server is also a finagle server (or any other supporting this extension), we reply to the request, and every subsequent request is dispatched with an envelope carrying trace metadata. The envelope itself is also a Thrift struct described here.

    Clients

    Clients can be created directly from an interface generated from a Thrift IDL:

    For example, this IDL:

    service TestService {
      string query(1: string x)
    }

    compiled with Scrooge, generates the interface TestService.FutureIface. This is then passed into Thrift.Client.newIface:

    Thrift.client.newIface[TestService.FutureIface](
      addr, classOf[TestService.FutureIface])

    However note that the Scala compiler can insert the latter Class for us, for which another variant of newIface is provided:

    Thrift.client.newIface[TestService.FutureIface](addr)

    In Java, we need to provide the class object:

    TestService.FutureIface client =
      Thrift.client.newIface(addr, TestService.FutureIface.class);

    The client uses the standard thrift protocols, with support for both framed and buffered transports. Finagle attempts to upgrade the protocol in order to ship an extra envelope carrying trace IDs and client IDs associated with the request. These are used by Finagle's tracing facilities and may be collected via aggregators like Zipkin.

    The negotiation is simple: on connection establishment, an improbably-named method is dispatched on the server. If that method isn't found, we are dealing with a legacy thrift server, and the standard protocol is used. If the remote server is also a finagle server (or any other supporting this extension), we reply to the request, and every subsequent request is dispatched with an envelope carrying trace metadata. The envelope itself is also a Thrift struct described here.

    Servers

    TestService.FutureIface must be implemented and passed into serveIface:

    // An echo service
    ThriftMux.server.serveIface(":*", new TestService.FutureIface {
      def query(x: String): Future[String] = Future.value(x)
    })
  44. object ThriftMux extends Client[ThriftClientRequest, Array[Byte]] with Server[Array[Byte], Array[Byte]]

    The ThriftMux object is both a com.twitter.finagle.Client and a com.twitter.finagle.Server for the Thrift protocol served over com.twitter.finagle.mux.

    The ThriftMux object is both a com.twitter.finagle.Client and a com.twitter.finagle.Server for the Thrift protocol served over com.twitter.finagle.mux. Rich interfaces are provided to adhere to those generated from a Thrift IDL by Scrooge or thrift-finagle.

    Clients

    Clients can be created directly from an interface generated from a Thrift IDL:

    For example, this IDL:

    service TestService {
      string query(1: string x)
    }

    compiled with Scrooge, generates the interface TestService.FutureIface. This is then passed into ThriftMux.Client.newIface:

    ThriftMux.client.newIface[TestService.FutureIface](
      addr, classOf[TestService.FutureIface])

    However note that the Scala compiler can insert the latter Class for us, for which another variant of newIface is provided:

    ThriftMux.client.newIface[TestService.FutureIface](addr)

    In Java, we need to provide the class object:

    TestService.FutureIface client =
      ThriftMux.client.newIface(addr, TestService.FutureIface.class);

    Servers

    Servers are also simple to expose:

    TestService.FutureIface must be implemented and passed into serveIface:

    // An echo service
    ThriftMux.server.serveIface(":*", new TestService.FutureIface {
      def query(x: String): Future[String] = Future.value(x)
    })

    This object does not expose any configuration options. Both clients and servers are instantiated with sane defaults. Clients are labeled with the "clnt/thrift" prefix and servers with "srv/thrift". If you'd like more configuration, see the configuration documentation.

  45. object WriteException extends Serializable
  46. object stack

Deprecated Value Members

  1. object Deadline extends Serializable
    Annotations
    @deprecated
    Deprecated

    (Since version 2016-08-22) Use com.twitter.finagle.context.Deadline instead

Inherited from AnyRef

Inherited from Any

Ungrouped