67 lines
2.9 KiB
Go
67 lines
2.9 KiB
Go
//
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// Copyright (c) 2023 Intel Corporation
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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package messaging
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import (
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"time"
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"github.com/edgexfoundry/go-mod-messaging/v4/pkg/types"
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)
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// MessageClient is the messaging interface for publisher-subscriber pattern
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type MessageClient interface {
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// Connect to messaging host specified in MessageBus config
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// returns error if not able to connect
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Connect() error
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// Publish is to send message to the message bus
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// the message contains data payload to send to the message bus
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Publish(message types.MessageEnvelope, topic string) error
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// PublishWithSizeLimit checks the message size in kilobytes after marshall and send it to the message bus
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// the message contains data payload to send to the message bus
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PublishWithSizeLimit(message types.MessageEnvelope, topic string, limit int64) error
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// Subscribe is to receive messages from topic channels
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// if message does not require a topic, then use empty string ("") for topic
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// the topic channel contains subscribed message channel and topic to associate with it
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// the channel is used for multiple threads of subscribers for 1 publisher (1-to-many)
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// the messageErrors channel returns the message errors from the caller
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// since subscriber works in asynchronous fashion
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// the function returns error for any subscribe error
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Subscribe(topics []types.TopicChannel, messageErrors chan error) error
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// Request publishes a request containing a RequestID to the specified topic,
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// then subscribes to a response topic which contains the RequestID. Once the response is received, the
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// response topic is unsubscribed and the response data is returned. If no response is received within
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// the timeout period, a timed out error returned.
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Request(message types.MessageEnvelope, requestTopic string, responseTopicPrefix string, timeout time.Duration) (*types.MessageEnvelope, error)
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// PublishBinaryData sends binary data to the message bus
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PublishBinaryData(data []byte, topic string) error
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// SubscribeBinaryData receives binary data from the specified topic, and wrap it in MessageEnvelope.
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SubscribeBinaryData(topics []types.TopicChannel, messageErrors chan error) error
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// Unsubscribe to unsubscribe from the specified topics.
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Unsubscribe(topics ...string) error
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// Disconnect is to close all connections on the message bus
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// and TopicChannel will also be closed
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Disconnect() error
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}
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