consumer

package
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 Go to latest Published: Jan 7, 2019 License: MIT Imports: 36 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var (
	ErrInvalidLengthConsumer = fmt.Errorf("proto: negative length found during unmarshaling")
	ErrIntOverflowConsumer   = fmt.Errorf("proto: integer overflow")
)
View Source 
var ReplicaStatus_Code_name = map[int32]string{
	0:   "IDLE",
	100: "BACKFILL",
	200: "TAILING",
	300: "PRIMARY",
	400: "FAILED",
}
View Source 
var ReplicaStatus_Code_value = map[string]int32{
	"IDLE":     0,
	"BACKFILL": 100,
	"TAILING":  200,
	"PRIMARY":  300,
	"FAILED":   400,
}
View Source 
var Status_name = map[int32]string{
	0: "OK",
	1: "SHARD_NOT_FOUND",
	2: "NO_SHARD_PRIMARY",
	3: "NOT_SHARD_PRIMARY",
	4: "ETCD_TRANSACTION_FAILED",
}
View Source 
var Status_value = map[string]int32{
	"OK":                      0,
	"SHARD_NOT_FOUND":         1,
	"NO_SHARD_PRIMARY":        2,
	"NOT_SHARD_PRIMARY":       3,
	"ETCD_TRANSACTION_FAILED": 4,
}

Functions

func ExtractShardSpecMetaLabels 

func ExtractShardSpecMetaLabels(spec *ShardSpec, out pb.LabelSet) pb.LabelSet

ExtractShardSpecMetaLabels returns meta-labels of the ShardSpec, using |out| as a buffer.

func NewKeySpace 

func NewKeySpace(prefix string) *keyspace.KeySpace

NewKeySpace returns a KeySpace suitable for use with an Allocator. It decodes allocator Items as ShardSpec messages, Members as ConsumerSpecs, and Assignments as RecoveryStatus enums.

func RegisterShardServer 

func RegisterShardServer(s *grpc.Server, srv ShardServer)

Types

type Application 

type Application interface {
	// NewStore constructs a Store for |shard| around the recovered local directory
	// |dir| and initialized Recorder |rec|.
	NewStore(shard Shard, dir string, rec *recoverylog.Recorder) (Store, error)
	// NewMessage returns a zero-valued Message of an appropriate representation
	// for the JournalSpec.
	NewMessage(*pb.JournalSpec) (message.Message, error)

	// ConsumeMessage consumes a message within the scope of a transaction.
	ConsumeMessage(Shard, Store, message.Envelope) error
	// FinalizeTxn indicates a consumer transaction is ending, and that the
	// Application must flush any in-memory transaction state or caches, and
	// issued any relevant journal writes. At completion all writes must have
	// been published to the Shard AsyncJournalClient, and all state must be captured
	// by the Store.
	FinalizeTxn(shard Shard, store Store) error
}

Application is the interface provided by domain applications running as Gazette consumers. Only unrecoverable errors should be returned by Application. A returned error will abort processing of an assigned Shard, and will update the assignment's ReplicaStatus to FAILED.

Gazette consumers process messages within pipelined transactions. A transaction begins upon receipt of a new message from a read journal at its present read offset. The message is consumed, and in the course of the transaction many more messages may be read & consumed. When consuming a message, the Application is free to consult the Store, to publish other messages to other journals via the Shard AsyncJournalClient, or to simply keep in-memory-only aggregates such as counts.

Eventually, either because of a read stall or maximum duration, the transaction will be finalized, at which point the Application must at least _start_ any related journal writes, and must reflect any in-memory caches or aggregates back into the Store.

The offsets which have been read through are also flushed to the Store at this time, and to disk, often as an atomic update mixed with Application state updates (when atomic writes are used, the framework provides an exactly-once guarantee over message state updates).

This final flush to the Store (and its recoverylog) is made dependent upon all other writes issued to the AsyncJournalClient, ensuring that read offsets are persisted only after related writes have completed, and thereby providing an at-least once guarantee for journal writes driven by the transaction.

Transactions are pipelined, which means that while asynchronous writes from the finalized transaction run to completion, another consumer transaction may begin processing concurrently. That new transaction is constrained only in that it may not itself finalize until all writes of its predecessor have fully committed to the brokers. If that takes so long that the successor transaction reaches its maximum duration, then that successor will stall without processing further messages until all predecessor writes commit.

type ApplyRequest 

type ApplyRequest struct {
	Changes []ApplyRequest_Change `protobuf:"bytes,1,rep,name=changes" json:"changes"`
}

func (*ApplyRequest) Descriptor 

func (*ApplyRequest) Descriptor() ([]byte, []int)

func (*ApplyRequest) Marshal 

func (m *ApplyRequest) Marshal() (dAtA []byte, err error)

func (*ApplyRequest) MarshalTo 

func (m *ApplyRequest) MarshalTo(dAtA []byte) (int, error)

func (*ApplyRequest) ProtoMessage 

func (*ApplyRequest) ProtoMessage()

func (*ApplyRequest) ProtoSize 

func (m *ApplyRequest) ProtoSize() (n int)

func (*ApplyRequest) Reset 

func (m *ApplyRequest) Reset()

func (*ApplyRequest) String 

func (m *ApplyRequest) String() string

func (*ApplyRequest) Unmarshal 

func (m *ApplyRequest) Unmarshal(dAtA []byte) error

func (*ApplyRequest) Validate 

func (m *ApplyRequest) Validate() error

Validate returns an error if the ApplyRequest is not well-formed.

func (*ApplyRequest) XXX_DiscardUnknown 

func (m *ApplyRequest) XXX_DiscardUnknown()

func (*ApplyRequest) XXX_Marshal 

func (m *ApplyRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ApplyRequest) XXX_Merge 

func (dst *ApplyRequest) XXX_Merge(src proto.Message)

func (*ApplyRequest) XXX_Size 

func (m *ApplyRequest) XXX_Size() int

func (*ApplyRequest) XXX_Unmarshal 

func (m *ApplyRequest) XXX_Unmarshal(b []byte) error

type ApplyRequest_Change 

type ApplyRequest_Change struct {
	// Expected ModRevision of the current ShardSpec. If the shard is being
	// created, expect_mod_revision is zero.
	ExpectModRevision int64 `protobuf:"varint,1,opt,name=expect_mod_revision,json=expectModRevision,proto3" json:"expect_mod_revision,omitempty"`
	// ShardSpec to be updated (if expect_mod_revision > 0) or created
	// (if expect_mod_revision == 0).
	Upsert *ShardSpec `protobuf:"bytes,2,opt,name=upsert" json:"upsert,omitempty"`
	// Shard to be deleted. expect_mod_revision must not be zero.
	Delete ShardID `protobuf:"bytes,3,opt,name=delete,proto3,casttype=ShardID" json:"delete,omitempty"`
}

Change defines an insertion, update, or deletion to be applied to the set of ShardSpecs. Exactly one of |upsert| or |delete| must be set.

func (*ApplyRequest_Change) Descriptor 

func (*ApplyRequest_Change) Descriptor() ([]byte, []int)

func (*ApplyRequest_Change) Marshal 

func (m *ApplyRequest_Change) Marshal() (dAtA []byte, err error)

func (*ApplyRequest_Change) MarshalTo 

func (m *ApplyRequest_Change) MarshalTo(dAtA []byte) (int, error)

func (*ApplyRequest_Change) ProtoMessage 

func (*ApplyRequest_Change) ProtoMessage()

func (*ApplyRequest_Change) ProtoSize 

func (m *ApplyRequest_Change) ProtoSize() (n int)

func (*ApplyRequest_Change) Reset 

func (m *ApplyRequest_Change) Reset()

func (*ApplyRequest_Change) String 

func (m *ApplyRequest_Change) String() string

func (*ApplyRequest_Change) Unmarshal 

func (m *ApplyRequest_Change) Unmarshal(dAtA []byte) error

func (*ApplyRequest_Change) Validate 

func (m *ApplyRequest_Change) Validate() error

Validate returns an error if the ApplyRequest_Change is not well-formed.

func (*ApplyRequest_Change) XXX_DiscardUnknown 

func (m *ApplyRequest_Change) XXX_DiscardUnknown()

func (*ApplyRequest_Change) XXX_Marshal 

func (m *ApplyRequest_Change) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ApplyRequest_Change) XXX_Merge 

func (dst *ApplyRequest_Change) XXX_Merge(src proto.Message)

func (*ApplyRequest_Change) XXX_Size 

func (m *ApplyRequest_Change) XXX_Size() int

func (*ApplyRequest_Change) XXX_Unmarshal 

func (m *ApplyRequest_Change) XXX_Unmarshal(b []byte) error

type ApplyResponse 

type ApplyResponse struct {
	// Status of the Update RPC.
	Status Status `protobuf:"varint,1,opt,name=status,proto3,enum=consumer.Status" json:"status,omitempty"`
	// Header of the response.
	Header protocol.Header `protobuf:"bytes,2,opt,name=header" json:"header"`
}

func ApplyShards 

func ApplyShards(ctx context.Context, sc ShardClient, req *ApplyRequest) (*ApplyResponse, error)

ApplyShards invokes the Apply RPC, and maps a validation or !OK status to an error.

func (*ApplyResponse) Descriptor 

func (*ApplyResponse) Descriptor() ([]byte, []int)

func (*ApplyResponse) Marshal 

func (m *ApplyResponse) Marshal() (dAtA []byte, err error)

func (*ApplyResponse) MarshalTo 

func (m *ApplyResponse) MarshalTo(dAtA []byte) (int, error)

func (*ApplyResponse) ProtoMessage 

func (*ApplyResponse) ProtoMessage()

func (*ApplyResponse) ProtoSize 

func (m *ApplyResponse) ProtoSize() (n int)

func (*ApplyResponse) Reset 

func (m *ApplyResponse) Reset()

func (*ApplyResponse) String 

func (m *ApplyResponse) String() string

func (*ApplyResponse) Unmarshal 

func (m *ApplyResponse) Unmarshal(dAtA []byte) error

func (*ApplyResponse) Validate 

func (m *ApplyResponse) Validate() error

Validate returns an error if the ApplyResponse is not well-formed.

func (*ApplyResponse) XXX_DiscardUnknown 

func (m *ApplyResponse) XXX_DiscardUnknown()

func (*ApplyResponse) XXX_Marshal 

func (m *ApplyResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ApplyResponse) XXX_Merge 

func (dst *ApplyResponse) XXX_Merge(src proto.Message)

func (*ApplyResponse) XXX_Size 

func (m *ApplyResponse) XXX_Size() int

func (*ApplyResponse) XXX_Unmarshal 

func (m *ApplyResponse) XXX_Unmarshal(b []byte) error

type BeginFinisher 

type BeginFinisher interface {
	// BeginTxn is called to notify the Application that a transaction is beginning
	// (and a call to ConsumeMessage will be immediately forthcoming), allowing
	// the Application to perform any preparatory work. For consumers doing
	// extensive aggregation, it may be beneficial to focus available compute
	// resource on a small number of transactions while completely stalling
	// others: this can be accomplished by blocking in BeginTxn until a semaphore
	// is acquired. A call to BeginTx is always paired with a call to FinishTxn.
	BeginTxn(Shard, Store) error
	// FinishTxn is notified that a begun transaction has completed, and should
	// perform any related cleanup (eg, releasing a previously acquired
	// semaphore). Note that, because transactions are pipelined, underlying
	// journal writes of the transaction may still be ongoing
	FinishTxn(Shard, Store)
}

BeginFinisher is an optional interface of Application which is informed when consumer transactions begin or finish.

type ConsumerSpec 

type ConsumerSpec struct {
	// ProcessSpec of the consumer.
	protocol.ProcessSpec `protobuf:"bytes,1,opt,name=process_spec,json=processSpec,embedded=process_spec" json:"process_spec" yaml:",inline"`
	// Maximum number of assigned Shards.
	ShardLimit uint32 `protobuf:"varint,2,opt,name=shard_limit,json=shardLimit,proto3" json:"shard_limit,omitempty"`
}

ConsumerSpec describes a Consumer process instance and its configuration. It serves as a allocator MemberValue.

func (*ConsumerSpec) Descriptor 

func (*ConsumerSpec) Descriptor() ([]byte, []int)

func (*ConsumerSpec) ItemLimit 

func (m *ConsumerSpec) ItemLimit() int

ItemLimit is the maximum number of shards this consumer may process. allocator.MemberValue implementation.

func (*ConsumerSpec) Marshal 

func (m *ConsumerSpec) Marshal() (dAtA []byte, err error)

func (*ConsumerSpec) MarshalString 

func (m *ConsumerSpec) MarshalString() string

MarshalString returns the marshaled encoding of the ConsumerSpec as a string.

func (*ConsumerSpec) MarshalTo 

func (m *ConsumerSpec) MarshalTo(dAtA []byte) (int, error)

func (*ConsumerSpec) ProtoMessage 

func (*ConsumerSpec) ProtoMessage()

func (*ConsumerSpec) ProtoSize 

func (m *ConsumerSpec) ProtoSize() (n int)

func (*ConsumerSpec) Reset 

func (m *ConsumerSpec) Reset()

func (*ConsumerSpec) String 

func (m *ConsumerSpec) String() string

func (*ConsumerSpec) Unmarshal 

func (m *ConsumerSpec) Unmarshal(dAtA []byte) error

func (*ConsumerSpec) Validate 

func (m *ConsumerSpec) Validate() error

Validate returns an error if the ConsumerSpec is not well-formed.

func (*ConsumerSpec) XXX_DiscardUnknown 

func (m *ConsumerSpec) XXX_DiscardUnknown()

func (*ConsumerSpec) XXX_Marshal 

func (m *ConsumerSpec) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ConsumerSpec) XXX_Merge 

func (dst *ConsumerSpec) XXX_Merge(src proto.Message)

func (*ConsumerSpec) XXX_Size 

func (m *ConsumerSpec) XXX_Size() int

func (*ConsumerSpec) XXX_Unmarshal 

func (m *ConsumerSpec) XXX_Unmarshal(b []byte) error

func (*ConsumerSpec) ZeroLimit 

func (m *ConsumerSpec) ZeroLimit()

ZeroLimit zeros the ConsumerSpec ShardLimit.

type JSONFileStore 

type JSONFileStore struct {
	// State is a user-provided instance which is un/marshal-able to JSON.
	State interface{}
	// contains filtered or unexported fields
}

JSONFileStore is a simple Store which materializes itself as a JSON-encoded file. The store is careful to flush to a new temporary file which is then moved to the well-known location: eg, a process failure cannot result in a recovery of a partially written JSON file.

func NewJSONFileStore 

func NewJSONFileStore(rec *recoverylog.Recorder, dir string, state interface{}) (*JSONFileStore, error)

NewJSONFileStore returns a new JSONFileStore. |state| is the runtime instance of the Store's state, which is decoded into, encoded from, and retained as JSONFileState.State.

func (*JSONFileStore) Destroy 

func (s *JSONFileStore) Destroy()

Destroy the JSONFileStore directory and state file.

func (*JSONFileStore) FetchJournalOffsets 

func (s *JSONFileStore) FetchJournalOffsets() (map[pb.Journal]int64, error)

FetchJournalOffsets returns offsets encoded by the JSONFileStore.

func (*JSONFileStore) Flush 

func (s *JSONFileStore) Flush(offsets map[pb.Journal]int64) error

Flush the store's JSONFileState to disk.

func (*JSONFileStore) Recorder 

func (s *JSONFileStore) Recorder() *recoverylog.Recorder

Recorder of the JSONFileStore.

type ListRequest 

type ListRequest struct {
	// Selector optionally refines the set of shards which will be enumerated.
	// If zero-valued, all shards are returned. Otherwise, only ShardSpecs
	// matching the LabelSelector will be returned. One meta-label "id" is
	// additionally supported by the selector, where "id=example-shard-ID"
	// will match a ShardSpec with ID "example-shard-ID".
	Selector protocol.LabelSelector `protobuf:"bytes,1,opt,name=selector" json:"selector"`
}

func (*ListRequest) Descriptor 

func (*ListRequest) Descriptor() ([]byte, []int)

func (*ListRequest) Marshal 

func (m *ListRequest) Marshal() (dAtA []byte, err error)

func (*ListRequest) MarshalTo 

func (m *ListRequest) MarshalTo(dAtA []byte) (int, error)

func (*ListRequest) ProtoMessage 

func (*ListRequest) ProtoMessage()

func (*ListRequest) ProtoSize 

func (m *ListRequest) ProtoSize() (n int)

func (*ListRequest) Reset 

func (m *ListRequest) Reset()

func (*ListRequest) String 

func (m *ListRequest) String() string

func (*ListRequest) Unmarshal 

func (m *ListRequest) Unmarshal(dAtA []byte) error

func (*ListRequest) Validate 

func (m *ListRequest) Validate() error

Validate returns an error if the ListRequest is not well-formed.

func (*ListRequest) XXX_DiscardUnknown 

func (m *ListRequest) XXX_DiscardUnknown()

func (*ListRequest) XXX_Marshal 

func (m *ListRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ListRequest) XXX_Merge 

func (dst *ListRequest) XXX_Merge(src proto.Message)

func (*ListRequest) XXX_Size 

func (m *ListRequest) XXX_Size() int

func (*ListRequest) XXX_Unmarshal 

func (m *ListRequest) XXX_Unmarshal(b []byte) error

type ListResponse 

type ListResponse struct {
	// Status of the List RPC.
	Status Status `protobuf:"varint,1,opt,name=status,proto3,enum=consumer.Status" json:"status,omitempty"`
	// Header of the response.
	Header protocol.Header      `protobuf:"bytes,2,opt,name=header" json:"header"`
	Shards []ListResponse_Shard `protobuf:"bytes,3,rep,name=shards" json:"shards"`
}

func ListShards 

func ListShards(ctx context.Context, sc ShardClient, req *ListRequest) (*ListResponse, error)

ListShards invokes the List RPC, and maps a validation or !OK status to an error.

func (*ListResponse) Descriptor 

func (*ListResponse) Descriptor() ([]byte, []int)

func (*ListResponse) Marshal 

func (m *ListResponse) Marshal() (dAtA []byte, err error)

func (*ListResponse) MarshalTo 

func (m *ListResponse) MarshalTo(dAtA []byte) (int, error)

func (*ListResponse) ProtoMessage 

func (*ListResponse) ProtoMessage()

func (*ListResponse) ProtoSize 

func (m *ListResponse) ProtoSize() (n int)

func (*ListResponse) Reset 

func (m *ListResponse) Reset()

func (*ListResponse) String 

func (m *ListResponse) String() string

func (*ListResponse) Unmarshal 

func (m *ListResponse) Unmarshal(dAtA []byte) error

func (*ListResponse) Validate 

func (m *ListResponse) Validate() error

Validate returns an error if the ListResponse is not well-formed.

func (*ListResponse) XXX_DiscardUnknown 

func (m *ListResponse) XXX_DiscardUnknown()

func (*ListResponse) XXX_Marshal 

func (m *ListResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ListResponse) XXX_Merge 

func (dst *ListResponse) XXX_Merge(src proto.Message)

func (*ListResponse) XXX_Size 

func (m *ListResponse) XXX_Size() int

func (*ListResponse) XXX_Unmarshal 

func (m *ListResponse) XXX_Unmarshal(b []byte) error

type ListResponse_Shard 

type ListResponse_Shard struct {
	Spec ShardSpec `protobuf:"bytes,1,opt,name=spec" json:"spec"`
	// Current ModRevision of the ShardSpec.
	ModRevision int64 `protobuf:"varint,2,opt,name=mod_revision,json=modRevision,proto3" json:"mod_revision,omitempty"`
	// Route of the shard, including endpoints.
	Route protocol.Route `protobuf:"bytes,3,opt,name=route" json:"route"`
	// Status of each replica. Cardinality and ordering matches |route|.
	Status []ReplicaStatus `protobuf:"bytes,4,rep,name=status" json:"status"`
}

Shards of the response.

func (*ListResponse_Shard) Descriptor 

func (*ListResponse_Shard) Descriptor() ([]byte, []int)

func (*ListResponse_Shard) Marshal 

func (m *ListResponse_Shard) Marshal() (dAtA []byte, err error)

func (*ListResponse_Shard) MarshalTo 

func (m *ListResponse_Shard) MarshalTo(dAtA []byte) (int, error)

func (*ListResponse_Shard) ProtoMessage 

func (*ListResponse_Shard) ProtoMessage()

func (*ListResponse_Shard) ProtoSize 

func (m *ListResponse_Shard) ProtoSize() (n int)

func (*ListResponse_Shard) Reset 

func (m *ListResponse_Shard) Reset()

func (*ListResponse_Shard) String 

func (m *ListResponse_Shard) String() string

func (*ListResponse_Shard) Unmarshal 

func (m *ListResponse_Shard) Unmarshal(dAtA []byte) error

func (*ListResponse_Shard) Validate 

func (m *ListResponse_Shard) Validate() error

Validate returns an error if the ListResponse_Shard is not well-formed.

func (*ListResponse_Shard) XXX_DiscardUnknown 

func (m *ListResponse_Shard) XXX_DiscardUnknown()

func (*ListResponse_Shard) XXX_Marshal 

func (m *ListResponse_Shard) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ListResponse_Shard) XXX_Merge 

func (dst *ListResponse_Shard) XXX_Merge(src proto.Message)

func (*ListResponse_Shard) XXX_Size 

func (m *ListResponse_Shard) XXX_Size() int

func (*ListResponse_Shard) XXX_Unmarshal 

func (m *ListResponse_Shard) XXX_Unmarshal(b []byte) error

type Replica 

type Replica struct {
	// contains filtered or unexported fields
}

Replica of a shard which is processed locally.

func NewReplica 

func NewReplica(app Application, ks *keyspace.KeySpace, etcd *clientv3.Client, rjc pb.RoutedJournalClient) *Replica

NewReplica returns a Replica in its initial state. The Replica must be transitioned by Resolver to begin processing of a shard.

func (*Replica) Assignment 

func (r *Replica) Assignment() keyspace.KeyValue

Assignment of the ShardSpec to the local ConsumerSpec, which motivates this Replica.

func (*Replica) Context 

func (r *Replica) Context() context.Context

Context of the Replica.

func (*Replica) JournalClient 

func (r *Replica) JournalClient() client.AsyncJournalClient

JournalClient for broker operations performed in the course of processing this Replica.

func (*Replica) Spec 

func (r *Replica) Spec() *ShardSpec

Spec of the Replica shard.

func (*Replica) WaitAndTearDown 

func (r *Replica) WaitAndTearDown()

WaitAndTearDown waits for all outstanding goroutines which are accessing the Replica, and for all pending Appends to complete, and then tears down the store.

type ReplicaStatus 

type ReplicaStatus struct {
	Code ReplicaStatus_Code `protobuf:"varint,1,opt,name=code,proto3,enum=consumer.ReplicaStatus_Code" json:"code,omitempty"`
	// Errors encountered during replica processing. Set iff |code| is FAILED.
	Errors []string `protobuf:"bytes,2,rep,name=errors" json:"errors,omitempty"`
}

ReplicaStatus is the status of a ShardSpec assigned to a ConsumerSpec. It serves as an allocator AssignmentValue. ReplicaStatus is reduced by taking the maximum enum value amoung statuses. Eg, if a primary is PRIMARY, one replica is BACKFILL and the other TAILING, then the status is PRIMARY. If one of the replicas transitioned to FAILED, than the status is FAILED. This reduction behavior is used to summarize status across all replicas.

func (*ReplicaStatus) Descriptor 

func (*ReplicaStatus) Descriptor() ([]byte, []int)

func (*ReplicaStatus) Marshal 

func (m *ReplicaStatus) Marshal() (dAtA []byte, err error)

func (*ReplicaStatus) MarshalString 

func (m *ReplicaStatus) MarshalString() string

MarshalString returns the marshaled encoding of the ReplicaStatus as a string.

func (*ReplicaStatus) MarshalTo 

func (m *ReplicaStatus) MarshalTo(dAtA []byte) (int, error)

func (*ReplicaStatus) ProtoMessage 

func (*ReplicaStatus) ProtoMessage()

func (*ReplicaStatus) ProtoSize 

func (m *ReplicaStatus) ProtoSize() (n int)

func (*ReplicaStatus) Reduce 

func (m *ReplicaStatus) Reduce(other *ReplicaStatus)

Reduce folds another ReplicaStatus into this one.

func (*ReplicaStatus) Reset 

func (m *ReplicaStatus) Reset()

func (*ReplicaStatus) String 

func (m *ReplicaStatus) String() string

func (*ReplicaStatus) Unmarshal 

func (m *ReplicaStatus) Unmarshal(dAtA []byte) error

func (*ReplicaStatus) Validate 

func (m *ReplicaStatus) Validate() error

Validate returns an error if the ReplicaStatus is not well-formed.

func (*ReplicaStatus) XXX_DiscardUnknown 

func (m *ReplicaStatus) XXX_DiscardUnknown()

func (*ReplicaStatus) XXX_Marshal 

func (m *ReplicaStatus) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ReplicaStatus) XXX_Merge 

func (dst *ReplicaStatus) XXX_Merge(src proto.Message)

func (*ReplicaStatus) XXX_Size 

func (m *ReplicaStatus) XXX_Size() int

func (*ReplicaStatus) XXX_Unmarshal 

func (m *ReplicaStatus) XXX_Unmarshal(b []byte) error

type ReplicaStatus_Code 

type ReplicaStatus_Code int32
const (
	ReplicaStatus_IDLE ReplicaStatus_Code = 0
	// The replica is actively playing the historical log.
	ReplicaStatus_BACKFILL ReplicaStatus_Code = 100
	// The replica has finished playing the historical log, and is tailing the
	// live log to locally mirror recorded operations as they are produced. It
	// is a "hot standby" and can take over as primary at any time.
	ReplicaStatus_TAILING ReplicaStatus_Code = 200
	// The replica is actively serving as primary.
	ReplicaStatus_PRIMARY ReplicaStatus_Code = 300
	// The replica has encountered an unrecoverable error.
	ReplicaStatus_FAILED ReplicaStatus_Code = 400
)

func (ReplicaStatus_Code) EnumDescriptor 

func (ReplicaStatus_Code) EnumDescriptor() ([]byte, []int)

func (ReplicaStatus_Code) String 

func (x ReplicaStatus_Code) String() string

func (ReplicaStatus_Code) Validate 

func (x ReplicaStatus_Code) Validate() error

Validate returns an error if the ReplicaStatus_Code is not well-formed.

type Resolution 

type Resolution struct {
	Status Status
	// Header captures the resolved consumer ProcessId, effective Etcd Revision,
	// and Route of the shard resolution.
	Header pb.Header
	// Spec of the Shard at the current Etcd revision.
	Spec *ShardSpec
	// Shard processing context, or nil if this process is not primary for the ShardID.
	Shard Shard
	// Store of the Shard, or nil if this process is not primary for the ShardID.
	Store Store
	// Done releases Shard & Store, and must be called when no longer needed.
	// Iff Shard & Store are nil, so is Done.
	Done func()
}

Resolution result of a ShardID.

type ResolveArgs 

type ResolveArgs struct {
	Context context.Context
	// ShardID to be resolved.
	ShardID ShardID
	// Whether we may resolve to another consumer peer.
	MayProxy bool
	// Optional Header attached to the request from a proxy-ing peer.
	ProxyHeader *pb.Header
}

ResolveArgs which parametrize resolution of ShardIDs.

type Resolver 

type Resolver struct {
	// contains filtered or unexported fields
}

Resolver maps shards to responsible consumer processes, and manages the set of local shard Replicas which are assigned to the local ConsumerSpec.

func NewResolver 

func NewResolver(state *allocator.State, newReplica func() *Replica) *Resolver

NewResolver returns a Resolver derived from the allocator.State, which will use the |newReplica| closure to instantiate Replicas for Assignments of the local ConsumerSpec.

func (*Resolver) Resolve 

func (r *Resolver) Resolve(args ResolveArgs) (res Resolution, err error)

Resolve a ShardID to its Resolution.

type RocksDBStore 

type RocksDBStore struct {
	DB           *rocks.DB
	Env          *rocks.Env
	Options      *rocks.Options
	ReadOptions  *rocks.ReadOptions
	WriteBatch   *rocks.WriteBatch
	WriteOptions *rocks.WriteOptions

	// Cache is a convenient mechanism for consumers to associate shard-specific,
	// in-memory state with a RocksDBStore, typically for performance reasons.
	// Examples might include:
	//
	// - Records we expect to reduce / aggregate over multiple times in a consumer
	//   transaction, and want to write to the DB only once per transaction (ie,
	//   as part of a consumer Flush).
	// - An LRU of "hot" records we expect to reference again soon.
	//
	// The representation of Cache is up to the consumer; it is not directly used
	// by RocksDBStore.
	Cache interface{}
	// contains filtered or unexported fields
}

RocksDBStore implements the Store interface.

func NewRocksDBStore 

func NewRocksDBStore(rec *recoverylog.Recorder, dir string) *RocksDBStore

NewRocksDBStore builds a RocksDBStore which is prepared to open its database, but has not yet done so. The caller may wish to further tweak Options and Env settings, and should then call Open to open the database.

func (*RocksDBStore) Destroy 

func (s *RocksDBStore) Destroy()

Destroy the RocksDBStore

func (*RocksDBStore) FetchJournalOffsets 

func (s *RocksDBStore) FetchJournalOffsets() (offsets map[pb.Journal]int64, err error)

FetchJournalOffsets returns a map of Journals and offsets captured by the DB.

func (*RocksDBStore) Flush 

func (s *RocksDBStore) Flush(offsets map[pb.Journal]int64) error

Flush merges |offsets| into the WriteBatch, and atomically writes it to the DB.

func (*RocksDBStore) Open 

func (s *RocksDBStore) Open() (err error)

Open the RocksDB. After Open, further updates to Env or Options are ignored.

func (*RocksDBStore) Recorder 

func (s *RocksDBStore) Recorder() *recoverylog.Recorder

Recorder of the RocksDB.

type RoutedShardClient 

type RoutedShardClient interface {
	ShardClient
	pb.DispatchRouter
}

RoutedShardClient composes a ShardClient and DispatchRouter.

func NewRoutedShardClient 

func NewRoutedShardClient(sc ShardClient, dr pb.DispatchRouter) RoutedShardClient

NewRoutedShardClient composes a ShardClient and DispatchRouter.

type Service 

type Service struct {
	// Resolver of Service shards.
	Resolver *Resolver
	// Loopback connection which defaults to the local server, but is wired with
	// a protocol.DispatchBalancer. Consumer applications may use Loopback proxy
	// application-specific RPCs to peer consumer instances, after performing
	// shard resolution.
	Loopback *grpc.ClientConn
	// Journal client for use by consumer applications.
	Journals pb.RoutedJournalClient
	// contains filtered or unexported fields
}

Service is the top-level runtime concern of a Gazette Consumer process. It drives local shard processing in response to allocator.State, powers shard resolution, and is also an implementation of ShardServer.

func NewService 

func NewService(app Application, state *allocator.State, rjc pb.RoutedJournalClient, lo *grpc.ClientConn, etcd *clientv3.Client) *Service

NewService constructs a new Service of the Application, driven by allocator.State.

func (*Service) Apply 

func (srv *Service) Apply(ctx context.Context, req *ApplyRequest) (*ApplyResponse, error)

Apply dispatches the ShardServer.Apply API.

func (*Service) List 

func (srv *Service) List(ctx context.Context, req *ListRequest) (*ListResponse, error)

List dispatches the ShardServer.List API.

func (*Service) Specs 

func (svc *Service) Specs() (out []*ShardSpec)

Specs returns the current collection of ShardSpecs.

type Shard 

type Shard interface {
	// Context of this shard. Notably, the Context will be cancelled when this
	// process is no longer responsible for the shard.
	Context() context.Context
	// Spec of the shard.
	Spec() *ShardSpec
	// Assignment of the shard to this process.
	Assignment() keyspace.KeyValue
	// JournalClient for broker operations performed in the course of processing
	// this Shard. Applications should use this AsyncJournalClient to allow
	// consumer transactions to track and appropriately sync on written journals.
	JournalClient() client.AsyncJournalClient
}

Shard is the processing context of a ShardSpec which is assigned to the local consumer process.

type ShardClient 

type ShardClient interface {
	// List Shards, their ShardSpecs and their processing status.
	List(ctx context.Context, in *ListRequest, opts ...grpc.CallOption) (*ListResponse, error)
	// Apply changes to the collection of Shards managed by the consumer.
	Apply(ctx context.Context, in *ApplyRequest, opts ...grpc.CallOption) (*ApplyResponse, error)
}

ShardClient is the client API for Shard service.

For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.

func NewShardClient 

func NewShardClient(cc *grpc.ClientConn) ShardClient

type ShardID 

type ShardID string

ShardID uniquely identifies a shard processed by a Gazette consumer.

func (ShardID) String 

func (id ShardID) String() string

String returns the Shard as a string.

func (ShardID) Validate 

func (id ShardID) Validate() error

Validate returns an error if the Shard is not well-formed.

type ShardServer 

type ShardServer interface {
	// List Shards, their ShardSpecs and their processing status.
	List(context.Context, *ListRequest) (*ListResponse, error)
	// Apply changes to the collection of Shards managed by the consumer.
	Apply(context.Context, *ApplyRequest) (*ApplyResponse, error)
}

ShardServer is the server API for Shard service.

type ShardSpec 

type ShardSpec struct {
	// ID of the Shard.
	Id ShardID `protobuf:"bytes,1,opt,name=id,proto3,casttype=ShardID" json:"id,omitempty"`
	// Sources of the shard, uniquely ordered on Source journal.
	Sources []ShardSpec_Source `protobuf:"bytes,2,rep,name=sources" json:"sources"`
	// Recovery log into which the Shard's database is replicated.
	RecoveryLog github_com_LiveRamp_gazette_v2_pkg_protocol.Journal `` /* 175-byte string literal not displayed */
	// Etcd keys into which recoverylog.FSMHints are written to and read from.
	// FSMHints allow readers of the recoverylog to efficiently determine the
	// minimum fragments of log which must be read to fully recover database state.
	// The current primary will regularly produce updated hints into hint_keys[0].
	// New players of the log will similarly utilize hints from hint_keys[0].
	// At least one |hint_keys| must be provided.
	//
	// Additional hint_keys beyond the first are a disaster-recovery mechanism:
	// On completing playback, a player will write the hints it recovered to
	// hint_keys[1], shifting the prior value of hint_keys[1] => hint_keys[2],
	// and so on for as many |hint_keys| as are specified. In the case of disaster
	// data-loss, these copied hints can be a helpful fallback for recovering a
	// consistent albiet older version of the Shard database, relying on only
	// progressively older portions of the recoverylog.
	//
	// When pruning the recoverylog, log fragments which are older than and no
	// longer required by the *last* of |hint_keys| are discarded, ensuring that
	// all of |hint_keys| remain valid for playback.
	HintKeys []string `protobuf:"bytes,4,rep,name=hint_keys,json=hintKeys" json:"hint_keys,omitempty" yaml:"hint_keys"`
	// Max duration of shard transactions. This duration upper-bounds the amount
	// of time during which a transaction may process messages before it must flush
	// and commit. It may run for less time if an input message stall occurs (eg,
	// no decoded journal message is ready without blocking). A typical value
	// would be `1s`: applications which perform extensive aggregation over message
	// streams exhibiting locality of "hot" keys may benefit from larger values.
	MaxTxnDuration time.Duration `` /* 134-byte string literal not displayed */
	// Min duration of shard transactions. This duration lower-bounds the amount
	// of time during which a transaction must process messages before it may flush
	// and commit. It may run for more time if additional messages are available
	// (eg, decoded journal messages are ready without blocking). Note also that
	// transactions are pipelined: a current transaction may process messages while
	// a prior transaction's recoverylog writes flush to Gazette, but it cannot
	// begin to commit until the prior transaction writes complete. In other words
	// even if |min_txn_quantum| is zero, some degree of message batching is
	// expected due to the network delay inherent in Gazette writes. A typical
	// value of would be `0s`: applications which perform extensive aggregation
	// may benefit from larger values.
	MinTxnDuration time.Duration `` /* 134-byte string literal not displayed */
	// Disable processing of the Shard.
	Disable bool `protobuf:"varint,7,opt,name=disable,proto3" json:"disable,omitempty"`
	// Hot standbys is the desired number of consumer processes which should be
	// replicating the primary consumer's recovery log. Standbys are allocated in
	// a separate availability zone of the current primary, and tail the live log
	// to continuously mirror the primary's on-disk DB file structure. Should the
	// primary experience failure, one of the hot standbys will be assigned to take
	// over as the new shard primary, which is accomplished by simply opening its
	// local copy of the RocksDB.
	//
	// Note that under regular operation, Shard hand-off is zero downtime even if
	// standbys are zero, as the current primary will not cede ownership until the
	// replacement process has completed log playback. However, a process failure
	// will leave the Shard without an owner until log playback can complete.
	HotStandbys uint32 `protobuf:"varint,8,opt,name=hot_standbys,json=hotStandbys,proto3" json:"hot_standbys,omitempty" yaml:"hot_standbys"`
	// User-defined Labels of this ShardSpec. The label "id" is reserved and may
	// not be used with a ShardSpec's labels.
	protocol.LabelSet `protobuf:"bytes,9,opt,name=labels,embedded=labels" json:"labels" yaml:",omitempty,inline"`
}

ShardSpec describes a shard and its configuration. Shards represent the combination of a consumer application, a specific journal selected for consumption, and a recoverylog journal which replicates the stateful consumption of that journal by the consumer. ShardSpec serves as a allocator ItemValue.

func (*ShardSpec) Descriptor 

func (*ShardSpec) Descriptor() ([]byte, []int)

func (*ShardSpec) DesiredReplication 

func (m *ShardSpec) DesiredReplication() int

DesiredReplication is the desired number of shard replicas. allocator.ItemValue implementation.

func (*ShardSpec) IsConsistent 

func (m *ShardSpec) IsConsistent(assignment keyspace.KeyValue, _ keyspace.KeyValues) bool

IsConsistent is whether the shard assignment is consistent. allocator.ItemValue implementation.

func (*ShardSpec) Marshal 

func (m *ShardSpec) Marshal() (dAtA []byte, err error)

func (*ShardSpec) MarshalString 

func (m *ShardSpec) MarshalString() string

MarshalString returns the marshaled encoding of the ShardSpec as a string.

func (*ShardSpec) MarshalTo 

func (m *ShardSpec) MarshalTo(dAtA []byte) (int, error)

func (*ShardSpec) ProtoMessage 

func (*ShardSpec) ProtoMessage()

func (*ShardSpec) ProtoSize 

func (m *ShardSpec) ProtoSize() (n int)

func (*ShardSpec) Reset 

func (m *ShardSpec) Reset()

func (*ShardSpec) String 

func (m *ShardSpec) String() string

func (*ShardSpec) Unmarshal 

func (m *ShardSpec) Unmarshal(dAtA []byte) error

func (*ShardSpec) Validate 

func (m *ShardSpec) Validate() error

Validate returns an error if the ShardSpec is not well-formed.

func (*ShardSpec) XXX_DiscardUnknown 

func (m *ShardSpec) XXX_DiscardUnknown()

func (*ShardSpec) XXX_Marshal 

func (m *ShardSpec) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ShardSpec) XXX_Merge 

func (dst *ShardSpec) XXX_Merge(src proto.Message)

func (*ShardSpec) XXX_Size 

func (m *ShardSpec) XXX_Size() int

func (*ShardSpec) XXX_Unmarshal 

func (m *ShardSpec) XXX_Unmarshal(b []byte) error

type ShardSpec_Source 

type ShardSpec_Source struct {
	// Journal which this Shard is consuming.
	Journal github_com_LiveRamp_gazette_v2_pkg_protocol.Journal `` /* 128-byte string literal not displayed */
	// Minimum journal byte offset the shard should begin reading from. Typically
	// this should be zero, as read offsets are persisted to and recovered from
	// the shard store as the journal is processed. |min_offset| can be useful
	// for shard initialization, directing it to skip over undesired historical
	// sections of the journal.
	MinOffset int64 `protobuf:"varint,3,opt,name=min_offset,json=minOffset,proto3" json:"min_offset,omitempty" yaml:"min_offset,omitempty"`
}

Sources define the set of Journals which this Shard consumes. At least one Source must be specified, and in many use cases only one will be needed. For advanced use cases which can benefit, multiple sources may be specified to represent a "join" over messages of distinct journals. Note the effective mapping of messages to each of the joined journals should align (eg, joining a journal of customer updates with one of orders, where both are mapped on customer ID). Another powerful pattern is to join each partition of a high-volume event stream with a low-volume journal of queries, obtaining a reliable distributed scatter/gather query engine.

func (*ShardSpec_Source) Descriptor 

func (*ShardSpec_Source) Descriptor() ([]byte, []int)

func (*ShardSpec_Source) Marshal 

func (m *ShardSpec_Source) Marshal() (dAtA []byte, err error)

func (*ShardSpec_Source) MarshalTo 

func (m *ShardSpec_Source) MarshalTo(dAtA []byte) (int, error)

func (*ShardSpec_Source) ProtoMessage 

func (*ShardSpec_Source) ProtoMessage()

func (*ShardSpec_Source) ProtoSize 

func (m *ShardSpec_Source) ProtoSize() (n int)

func (*ShardSpec_Source) Reset 

func (m *ShardSpec_Source) Reset()

func (*ShardSpec_Source) String 

func (m *ShardSpec_Source) String() string

func (*ShardSpec_Source) Unmarshal 

func (m *ShardSpec_Source) Unmarshal(dAtA []byte) error

func (*ShardSpec_Source) Validate 

func (m *ShardSpec_Source) Validate() error

Validate returns an error if the ShardSpec_Source is not well-formed.

func (*ShardSpec_Source) XXX_DiscardUnknown 

func (m *ShardSpec_Source) XXX_DiscardUnknown()

func (*ShardSpec_Source) XXX_Marshal 

func (m *ShardSpec_Source) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ShardSpec_Source) XXX_Merge 

func (dst *ShardSpec_Source) XXX_Merge(src proto.Message)

func (*ShardSpec_Source) XXX_Size 

func (m *ShardSpec_Source) XXX_Size() int

func (*ShardSpec_Source) XXX_Unmarshal 

func (m *ShardSpec_Source) XXX_Unmarshal(b []byte) error

type Status 

type Status int32

Status is a response status code, used across Gazette Consumer RPC APIs. 

const (
	Status_OK Status = 0
	// The named shard does not exist.
	Status_SHARD_NOT_FOUND Status = 1
	// There is no current primary consumer process for the shard. This is a
	// temporary condition which should quickly resolve, assuming sufficient
	// consumer capacity.
	Status_NO_SHARD_PRIMARY Status = 2
	// The present consumer process is not the assigned primary for the shard,
	// and was not instructed to proxy the request.
	Status_NOT_SHARD_PRIMARY Status = 3
	// The Etcd transaction failed. Returned by Update RPC when an
	// expect_mod_revision of the UpdateRequest differs from the current
	// ModRevision of the ShardSpec within the store.
	Status_ETCD_TRANSACTION_FAILED Status = 4
)

func (Status) EnumDescriptor 

func (Status) EnumDescriptor() ([]byte, []int)

func (Status) String 

func (x Status) String() string

func (Status) Validate 

func (x Status) Validate() error

Validate returns an error if the Status is not well-formed.

type Store 

type Store interface {
	// Recorder which this Store wraps, into which all Store state is recorded.
	Recorder() *recoverylog.Recorder
	// FetchJournalOffsets returns the collection of Journals and corresponding
	// offsets represented within the Store.
	FetchJournalOffsets() (map[pb.Journal]int64, error)
	// Flush |offsets| and any in-memory Store state to disk.
	Flush(offsets map[pb.Journal]int64) error
	// Destroy releases all resources and removes all local files associated
	// with the Store. It is guaranteed that the Store is no longer being used or
	// referenced at the onset of this call.
	Destroy()
}

Store is a stateful storage backend which is minimally able to record its file operations into a provided recoverylog.Recorder, and is able to represent a collection of Journal offsets. Application implementations control the selection, initialization, and usage of an appropriate Store backend for their use case.

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