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https://gitee.com/milvus-io/milvus.git
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119 lines
4.2 KiB
Go
119 lines
4.2 KiB
Go
package streaming
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import (
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"context"
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"time"
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kvfactory "github.com/milvus-io/milvus/internal/util/dependency/kv"
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"github.com/milvus-io/milvus/pkg/streaming/util/message"
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"github.com/milvus-io/milvus/pkg/streaming/util/options"
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"github.com/milvus-io/milvus/pkg/streaming/util/types"
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)
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var singleton WALAccesser = nil
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// Init initializes the wal accesser with the given etcd client.
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// should be called before any other operations.
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func Init() {
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c, _ := kvfactory.GetEtcdAndPath()
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singleton = newWALAccesser(c)
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}
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// Release releases the resources of the wal accesser.
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func Release() {
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if w, ok := singleton.(*walAccesserImpl); ok && w != nil {
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w.Close()
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}
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}
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// WAL is the entrance to interact with the milvus write ahead log.
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func WAL() WALAccesser {
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return singleton
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}
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// AppendOption is the option for append operation.
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type AppendOption struct {
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BarrierTimeTick uint64 // BarrierTimeTick is the barrier time tick of the message.
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// Must be allocated from tso, otherwise undetermined behavior.
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}
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type TxnOption struct {
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// VChannel is the target vchannel to write.
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// TODO: support cross-wal txn in future.
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VChannel string
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// Keepalive is the time to keepalive of the transaction.
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// If the txn don't append message in the keepalive time, the txn will be expired.
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// Only make sense when keepalive is greater than 1ms.
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// The default value is 0, which means the keepalive is setted by the wal at streaming node.
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Keepalive time.Duration
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}
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type ReadOption struct {
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// VChannel is the target vchannel to read.
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VChannel string
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// DeliverPolicy is the deliver policy of the consumer.
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DeliverPolicy options.DeliverPolicy
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// DeliverFilters is the deliver filters of the consumer.
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DeliverFilters []options.DeliverFilter
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// Handler is the message handler used to handle message after recv from consumer.
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MessageHandler message.Handler
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}
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// Scanner is the interface for reading records from the wal.
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type Scanner interface {
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// Done returns a channel which will be closed when scanner is finished or closed.
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Done() <-chan struct{}
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// Error returns the error of the scanner.
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Error() error
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// Close the scanner, release the underlying resources.
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Close()
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}
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// WALAccesser is the interfaces to interact with the milvus write ahead log.
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type WALAccesser interface {
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// Txn returns a transaction for writing records to the log.
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// Once the txn is returned, the Commit or Rollback operation must be called once, otherwise resource leak on wal.
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Txn(ctx context.Context, opts TxnOption) (Txn, error)
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// RawAppend writes a records to the log.
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RawAppend(ctx context.Context, msgs message.MutableMessage, opts ...AppendOption) (*types.AppendResult, error)
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// Read returns a scanner for reading records from the wal.
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Read(ctx context.Context, opts ReadOption) Scanner
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// AppendMessages appends messages to the wal.
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// It it a helper utility function to append messages to the wal.
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// If the messages is belong to one vchannel, it will be sent as a transaction.
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// Otherwise, it will be sent as individual messages.
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// !!! This function do not promise the atomicity and deliver order of the messages appending.
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// TODO: Remove after we support cross-wal txn.
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AppendMessages(ctx context.Context, msgs ...message.MutableMessage) AppendResponses
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// AppendMessagesWithOption appends messages to the wal with the given option.
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// Same with AppendMessages, but with the given option.
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// TODO: Remove after we support cross-wal txn.
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AppendMessagesWithOption(ctx context.Context, opts AppendOption, msgs ...message.MutableMessage) AppendResponses
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}
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// Txn is the interface for writing transaction into the wal.
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type Txn interface {
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// Append writes a record to the log.
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Append(ctx context.Context, msg message.MutableMessage, opts ...AppendOption) error
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// Commit commits the transaction.
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// Commit and Rollback can be only call once, and not concurrent safe with append operation.
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Commit(ctx context.Context) (*types.AppendResult, error)
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// Rollback rollbacks the transaction.
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// Commit and Rollback can be only call once, and not concurrent safe with append operation.
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// TODO: Manually rollback is make no sense for current single wal txn.
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// It is preserved for future cross-wal txn.
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Rollback(ctx context.Context) error
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}
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