CoAP Server
Constrained Application Protocol (CoAP) is a web transfer protocol designed for machine-to-machine devices. The CoAP Server origin is a multithreaded origin that listens on a CoAP endpoint and processes the contents of all authorized CoAP requests. For information about supported versions, see Supported Systems and Versions.
The CoAP Server origin can use multiple threads to enable parallel processing of data from multiple CoAP clients.
When the pipeline stops, the CoAP Server origin notes where it stops reading. When the pipeline starts again, the origin continues processing from where it stopped by default. You can reset the origin to process all requested data.
Before you configure the origin, perform additional steps to configure the CoAP clients.
When you configure the CoAP Server origin, you specify the maximum number of concurrent requests to determine how many threads to use. You also define the listening port and resource name for the origin. You can optionally override the default values of network configuration properties.
Prerequisites
Before you run a pipeline with the CoAP Server origin, configure the CoAP clients to send data to the CoAP Server listening port and resource.
When you configure the CoAP Server origin, you define a listening port number where the origin listens for data. You also define the resource name used to pass requests to the origin. To pass data to the pipeline, configure each CoAP client to send data to a URL that includes the listening port number and resource name.
coap://<sdc_hostname>:<listening_port>/<resource_name>
The URL includes the following components:
<sdc_hostname>
- The Data Collector host name.<listening_port>
- The port number where the origin listens for data.<resource_name>
- The resource name used to pass requests to the origin.
For example: coap://localhost:5683/sdc
Multithreaded Processing
The CoAP Server origin performs parallel processing and enables the creation of a multithreaded pipeline.
The CoAP Server origin uses multiple concurrent threads based on the Max Concurrent Requests property. Each thread connects to the origin system, creates a batch of data, and passes the batch to an available pipeline runner.
A pipeline runner is a sourceless pipeline instance - an instance of the pipeline that includes all of the processors, executors, and destinations in the pipeline and handles all pipeline processing after the origin. Each pipeline runner processes one batch at a time, just like a pipeline that runs on a single thread. When the flow of data slows, the pipeline runners wait idly until they are needed, generating an empty batch at regular intervals. You can configure the Runner Idle Time pipeline property to specify the interval or to opt out of empty batch generation.
Multithreaded pipelines preserve the order of records within each batch, just like a single-threaded pipeline. But since batches are processed by different pipeline runners, the order that batches are written to destinations is not ensured.
For example, say you set the Max Concurrent Requests property to 5. When you start the pipeline, the origin creates five threads, and Data Collector creates a matching number of pipeline runners. Upon receiving data, the origin passes a batch to each of the pipeline runners for processing.
At any given moment, the five pipeline runners can each process a batch, so this multithreaded pipeline processes up to five batches at a time. When incoming data slows, the pipeline runners sit idle, available for use as soon as the data flow increases.
For more information about multithreaded pipelines, see Multithreaded Pipeline Overview.
Network Configuration Properties
The CoAP Server origin uses the default values for network configuration properties as implemented by Eclipse Californium. If needed, you can override the default values of these properties.
- COAP_PORT - You set the port number in the CoAP Listening Port property for the origin.
- NETWORK_STAGE_RECEIVER_THREAD_COUNT - You set the number of threads in the Max Concurrent Requests property for the origin.
For example, the origin uses the default value of 2000 for the ACK_TIMEOUT network configuration property. To override the default value, add ACK_TIMEOUT as an additional network configuration property and set the property to the desired value, such as 1000.
Data Formats
The CoAP Server origin processes data differently based on the data format that you select. The origin processes the following types of data:
- Binary
- Generates a record with a single byte array field at the root of the record.
- Datagram
- Generates a record for every message. The origin can process collectd messages, NetFlow 5 and NetFlow 9 messages, and the following types of syslog messages:
- Delimited
- Generates a record for each delimited line.
- JSON
- Generates a record for each JSON object. You can process JSON files that include multiple JSON objects or a single JSON array.
- Log
- Generates a record for every log line.
- Protobuf
- Generates a record for every protobuf message. By default, the origin assumes messages contain multiple protobuf messages.
- SDC Record
- Generates a record for every record. Use to process records generated by a Data Collector pipeline using the SDC Record data format.
- Text
- Generates a record for each line of text or for each section of text based on a custom delimiter.
- XML
- Generates records based on a user-defined delimiter element. Use an XML element directly under the root element or define a simplified XPath expression. If you do not define a delimiter element, the origin treats the XML file as a single record.
Configuring a CoAP Server Origin
Configure a CoAP Server origin to generate multiple threads for parallel processing of CoAP client requests.