CoAP Server

Constrained Application Protocol (CoAP) is a web transfer protocol designed for machine-to-machine devices. The CoAP Server source is a multithreaded source 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 source can use multiple threads to enable parallel processing of data from multiple CoAP clients.

When the flow stops, the CoAP Server source notes where it stops reading. When the flow starts again, the source continues processing from where it stopped by default. You can reset the offset to process all requested data.

Before you configure the source, perform additional steps to configure the CoAP clients.

When you configure the CoAP Server source, 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 source. You can optionally override the default values of network configuration properties.

Prerequisites

Before you run a flow with the CoAP Server source, configure the CoAP clients to send data to the CoAP Server listening port and resource.

When you configure the CoAP Server source, you define a listening port number where the source listens for data. You also define the resource name used to pass requests to the source. To pass data to the flow, configure each CoAP client to send data to a URL that includes the listening port number and resource name.

Use the following format for the URL:

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 source listens for data.
<resource_name> - The resource name used to pass requests to the source.

For example: coap://localhost:5683/sdc

Multithreaded processing

The CoAP Server source performs parallel processing and enables the creation of a multithreaded flow.

The CoAP Server source uses multiple concurrent threads based on the Max Concurrent Requests property. Each thread connects to the source system, creates a batch of data, and passes the batch to an available flow runner.

A flow runner is a sourceless flow instance - an instance of the flow that includes all of the processors, executors, and targets in the flow and handles all flow processing after the source. Each flow runner processes one batch at a time, just like a flow that runs on a single thread. When the flow of data slows, the flow runners wait idly until they are needed, generating an empty batch at regular intervals. You can configure the Runner Idle Time flow property to specify the interval or to opt out of empty batch generation.

Multithreaded flows preserve the order of records within each batch, just like a single-threaded flow. But since batches are processed by different flow runners, the order that batches are written to targets is not ensured.

For example, say you set the Max Concurrent Requests property to 5. When you start the flow, the source creates five threads, and Data Collector creates a matching number of flow runners. Upon receiving data, the source passes a batch to each of the flow runners for processing.

At any given moment, the five flow runners can each process a batch, so this multithreaded flow processes up to five batches at a time. When incoming data slows, the flow runners sit idle, available for use as soon as the data flow increases.

For more information about multithreaded flows, see Multithreaded flow overview.

Network configuration properties

The CoAP Server source uses the default values for network configuration properties as implemented by Eclipse Californium. If needed, you can override the default values of these properties.

The default values of each property are listed on this page. The source uses the defaults for all network configuration properties except for the following:

COAP_PORT - You set the port number in the CoAP Listening Port property for the source.
NETWORK_STAGE_RECEIVER_THREAD_COUNT - You set the number of threads in the Max Concurrent Requests property for the source.

For example, the source 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 source processes data differently based on the data format that you select. The source processes the following types of data:

Binary

Generates a record with a single byte array field at the root of the record.

When the data exceeds the user-defined maximum data size, the source cannot process the data. Because the record is not created, the source cannot pass the record to the flow to be written as an error record. Instead, the source generates a stage error.

Datagram

Generates a record for every message. The source can process collectd messages, NetFlow 5 and NetFlow 9 messages, and the following types of syslog messages:

RFC 5424
RFC 3164
Non-standard common messages, such as RFC 3339 dates with no version digit

When processing NetFlow messages, the stage generates different records based on the NetFlow version. When processing NetFlow 9, the records are generated based on the NetFlow 9 configuration properties. For more information, see NetFlow data processing.

Delimited

Generates a record for each delimited line.

The CSV parser that you choose determines the delimiter properties that you configure and how the stage handles parsing errors. You can specify if the data includes a header line and whether to use it. You can define the number of lines to skip before reading, the character set of the data, and the root field type to use for the generated record.

You can also configure the stage to replace a string constant with null values and to ignore control characters.

For more information about reading delimited data, see Reading delimited data.

JSON

Generates a record for each JSON object. You can process JSON files that include multiple JSON objects or a single JSON array.

When an object exceeds the maximum object length defined for the source, the source processes the object based on the error handling configured for the stage.

Log

Generates a record for every log line.

When a line exceeds the user-defined maximum line length, the source truncates longer lines.

You can include the processed log line as a field in the record. If the log line is truncated, and you request the log line in the record, the source includes the truncated line.

You can define the log format or type to be read.

Protobuf

Generates a record for every protobuf message. By default, the source assumes messages contain multiple protobuf messages.

Protobuf messages must match the specified message type and be described in the descriptor file.

When the data for a record exceeds 1 MB, the source cannot continue processing data in the message. The source handles the message based on the stage error handling property and continues reading the next message.

For information about generating the descriptor file, see Protobuf data format prerequisites.

SDC Record

Generates a record for every record. Use to process records generated by a Data Collector flow using the SDC Record data format.

For error records, the source provides the original record as read from the source in the original flow, as well as error information that you can use to correct the record.

When processing error records, the source expects the error file names and contents as generated by the original flow.

Text

Generates a record for each line of text or for each section of text based on a custom delimiter.

When a line or section exceeds the maximum line length defined for the source, the source truncates it. The source adds a boolean field named Truncated to indicate if the line was truncated.

For more information about processing text with a custom delimiter, see Text data format with custom delimiters.

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 source treats the XML file as a single record.

Generated records include XML attributes and namespace declarations as fields in the record by default. You can configure the stage to include them in the record as field attributes.

You can include XPath information for each parsed XML element and XML attribute in field attributes. This also places each namespace in an xmlns record header attribute.

When a record exceeds the user-defined maximum record length, the source skips the record and continues processing with the next record. It sends the skipped record to the flow for error handling.

Use the XML data format to process valid XML documents. For more information about XML processing, see Reading and processing XML data.

Tip: If you want to process invalid XML documents, you can try using the text data format with custom delimiters. For more information, see Processing XML data with custom delimiters.

Configuring a CoAP Server source

About this task

Configure a CoAP Server source to generate multiple threads for parallel processing of CoAP client requests.

Procedure

In the Properties panel, on the General tab, configure the following properties:

General Property	Description
Name	Stage name.
Description	Optional description.
On Record Error	Error record handling for the stage: Discard - Discards the record. Send to Error - Sends the record to the flow for error handling. Stop Flow - Stops the flow.

On the CoAP tab, configure the following properties:

CoAP Property	Description
CoAP Listening Port	Listening port for the CoAP Server source. The port number must be included in the URL that the CoAP client uses to pass data. For more information, see Prerequisites.
Resource Name	Resource name used to pass requests to the CoAP Server source. The resource name must be included in the URL that the CoAP client uses to pass data. For more information, see Prerequisites.
Max Concurrent Requests	Maximum number of CoAP clients allowed to send requests to the source at one time. If the source reaches the configured maximum and receives additional requests from different clients, it processes those requests as slots become available. This property also determines how many threads the source generates and uses for multithreaded processing. For more information, see Multithreaded processing.
Network Configuration	Network configuration properties for which you want to override the default values. To add properties, click Add and define the property name and value. Use the property names and values as expected by Eclipse Californium.

On the Data Format tab, configure the following property:

Data Format Property	Description
Data Format	Type of data to be processed. Use one of the following options: Binary Datagram Delimited JSON Log Protobuf SDC Record Text XML

For binary data, on the Data Format tab, configure the following properties:

Binary Property	Description
Compression Format	The compression format of the files: None - Processes only uncompressed files. Compressed File - Processes files that are compressed by the supported compression formats. Archive - Processes files that are archived by the supported archive formats. Compressed Archive - Processes files that are archived and compressed by the supported archive and compression formats.
File Name Pattern within Compressed Directory	For archive and compressed archive files, file name pattern that represents the files to process within the compressed directory. You can use UNIX-style wildcards, such as an asterisk or question mark. For example, .json. Default is , which processes all files.
Max Data Size (bytes)	Maximum number of bytes in the message. Larger messages cannot be processed or written to error.

For datagram data, on the Data Format tab, configure the following properties:

Datagram Properties	Description
Datagram Packet Format	Packet format of the data: collectd NetFlow syslog Raw/separated data
TypesDB File Path	Path to a user-provided types.db file. Overrides the default types.db file. For collectd data only.
Auth File	Path to an optional authentication file. Use an authentication file to accept signed and encrypted data. For collectd data only.
Convert Hi-Res Time & Interval	Converts the collectd high resolution time format interval and timestamp to UNIX time, in milliseconds. For collectd data only.
Exclude Interval	Excludes the interval field from output record. For collectd data only.
Record Generation Mode	Determines the type of values to include in the record. Select one of the following options: Raw Only Interpreted Only Both Raw and Interpreted For NetFlow 9 data only.
Max Templates in Cache	The maximum number of templates to store in the template cache. For more information about templates, see Caching NetFlow 9 templates. Default is -1 for an unlimited cache size. For NetFlow 9 data only.
Template Cache Timeout (ms)	The maximum number of milliseconds to cache an idle template. Templates unused for more than the specified time are evicted from the cache. For more information about templates, see Caching NetFlow 9 templates. Default is -1 for caching templates indefinitely. For NetFlow 9 data only.
Charset	Character encoding of the messages to be processed.
Ignore Control Characters	Removes all ASCII control characters except for the tab, line feed, and carriage return characters.

For delimited data, on the Data Format tab, configure the following properties:

Delimited Property	Description
Header Line	Indicates whether a file contains a header line, and whether to use the header line.
Delimiter Format Type	Delimiter format type. Use one of the following options: Default CSV - File that includes comma-separated values. Ignores empty lines in the file. RFC4180 CSV - Comma-separated file that strictly follows RFC4180 guidelines. MS Excel CSV - Microsoft Excel comma-separated file. MySQL CSV - MySQL comma-separated file. Tab-Separated Values - File that includes tab-separated values. PostgreSQL CSV - PostgreSQL comma-separated file. PostgreSQL Text - PostgreSQL text file. Custom - File that uses user-defined delimiter, escape, and quote characters. Multi Character Delimited - File that uses multiple user-defined characters to delimit fields and lines, and single user-defined escape and quote characters. Available when using the Apache Commons parser type.
Multi Character Field Delimiter	Characters that delimit fields. Default is two pipe characters (\|\|). Available when using the Apache Commons parser with the multi-character delimiter format.
Multi Character Line Delimiter	Characters that delimit lines or records. Default is the newline character (\n). Available when using the Apache Commons parser with the multi-character delimiter format.
Delimiter Character	Delimiter character. Select one of the available options or use Other to enter a custom character. You can enter a Unicode control character using the format `\uNNNN`, where N is a hexadecimal digit from the numbers 0-9 or the letters A-F. For example, enter `\u0000` to use the null character as the delimiter or `\u2028` to use a line separator as the delimiter. Default is the pipe character ( \| ). Available when using the Apache Commons parser with a custom delimiter format.
Field Separator	One or more characters to use as delimiter characters between columns. Available when using the Univocity parser.
Escape Character	Escape character. Available when using the Apache Commons parser with the custom or multi-character delimiter format. Also available when using the Univocity parser.
Quote Character	Quote character. Available when using the Apache Commons parser with the custom or multi-character delimiter format. Also available when using the Univocity parser.
Line Separator	Line separator. Available when using the Univocity parser.
Allow Comments	Allows commented data to be ignored for custom delimiter format. Available when using the Univocity parser.
Comment Character	Character that marks a comment when comments are enabled for custom delimiter format. Available when using the Univocity parser.
Enable Comments	Allows commented data to be ignored for custom delimiter format. Available when using the Apache Commons parser.
Comment Marker	Character that marks a comment when comments are enabled for custom delimiter format. Available when using the Apache Commons parser.
Lines to Skip	Number of lines to skip before reading data.
Compression Format	The compression format of the files: None - Processes only uncompressed files. Compressed File - Processes files that are compressed by the supported compression formats. Archive - Processes files that are archived by the supported archive formats. Compressed Archive - Processes files that are archived and compressed by the supported archive and compression formats.
File Name Pattern within Compressed Directory	For archive and compressed archive files, file name pattern that represents the files to process within the compressed directory. You can use UNIX-style wildcards, such as an asterisk or question mark. For example, .json. Default is , which processes all files.
CSV Parser	Parser to use to process delimited data: Apache Commons - Provides robust parsing and a wide range of delimited format types. Univocity - Can provide faster processing for wide delimited files, such as those with over 200 columns. Default is Apache Commons.
Max Columns	Maximum number of columns to process per record. Available when using the Univocity parser.
Max Character per Column	Maximum number of characters to process in each column. Available when using the Univocity parser.
Skip Empty Lines	Allows skipping empty lines. Available when using the Univocity parser.
Allow Extra Columns	Allows processing records with more columns than exist in the header line. Available when using the Apache Commons parser to process data with a header line.
Extra Column Prefix	Prefix to use for any additional columns. Extra columns are named using the prefix and sequential increasing integers as follows: `<prefix><integer>`. For example, `_extra_1`. Default is `_extra_`. Available when using the Apache Commons parser to process data with a header line while allowing extra columns.
Max Record Length (chars)	Maximum length of a record in characters. Longer records are not read. This property can be limited by the Data Collector parser buffer size. For more information, see Maximum record size. Available when using the Apache Commons parser.
Ignore Empty Lines	Allows empty lines to be ignored. Available when using the Apache Commons parser with the custom delimiter format.
Root Field Type	Root field type to use: List-Map - Generates an indexed list of data. Enables you to use standard functions to process data. Use for new flows. List - Generates a record with an indexed list with a map for header and value. Requires the use of delimited data functions to process data. Use only to maintain flows created before 1.1.0.
Parse NULLs	Replaces the specified string constant with null values.
NULL Constant	String constant to replace with null values.
Charset	Character encoding of the files to be processed.
Ignore Control Characters	Removes all ASCII control characters except for the tab, line feed, and carriage return characters.

For JSON data, on the Data Format tab, configure the following properties:

JSON Property	Description
JSON Content	Type of JSON content. Use one of the following options: JSON array of objects Multiple JSON objects
Compression Format	The compression format of the files: None - Processes only uncompressed files. Compressed File - Processes files that are compressed by the supported compression formats. Archive - Processes files that are archived by the supported archive formats. Compressed Archive - Processes files that are archived and compressed by the supported archive and compression formats.
File Name Pattern within Compressed Directory	For archive and compressed archive files, file name pattern that represents the files to process within the compressed directory. You can use UNIX-style wildcards, such as an asterisk or question mark. For example, .json. Default is , which processes all files.
Max Object Length (chars)	Maximum number of characters in a JSON object. Longer objects are diverted to the flow for error handling. This property can be limited by the Data Collector parser buffer size. For more information, see Maximum record size.
Charset	Character encoding of the files to be processed.
Ignore Control Characters	Removes all ASCII control characters except for the tab, line feed, and carriage return characters.

For log data, on the Data Format tab, configure the following properties:

Log Property	Description
Log Format	Format of the log files. Use one of the following options: Common Log Format Combined Log Format Apache Error Log Format Apache Access Log Custom Format Regular Expression Grok Pattern Log4j Common Event Format (CEF) Log Event Extended Format (LEEF)
Max Line Length	Maximum length of a log line. The source truncates longer lines. This property can be limited by the Data Collector parser buffer size. For more information, see Maximum record size.
Retain Original Line	Determines how to treat the original log line. Select to include the original log line as a field in the resulting record. By default, the original line is discarded.
Charset	Character encoding of the files to be processed.
Ignore Control Characters	Removes all ASCII control characters except for the tab, line feed, and carriage return characters.

When you select Apache Access Log Custom Format, use Apache log format strings to define the Custom Log Format.
When you select Regular Expression, enter the regular expression that describes the log format, and then map the fields that you want to include to each regular expression group.
When you select Grok Pattern, you can use the Grok Pattern Definition field to define custom grok patterns. You can define a pattern on each line.
In the Grok Pattern field, enter the pattern to use to parse the log. You can use a predefined grok patterns or create a custom grok pattern using patterns defined in Grok Pattern Definition.

For more information about defining grok patterns and supported grok patterns, see Defining grok patterns.

When you select Log4j, define the following properties:

Log4j Property	Description
On Parse Error	Determines how to handle information that cannot be parsed: Skip and Log Error - Skips reading the line and logs a stage error. Skip, No Error - Skips reading the line and does not log an error. Include as Stack Trace - Includes information that cannot be parsed as a stack trace to the previously-read log line. The information is added to the message field for the last valid log line.
Use Custom Log Format	Allows you to define a custom log format.
Custom Log4J Format	Use log4j variables to define a custom log format.

For protobuf data, on the Data Format tab, configure the following properties:

Protobuf Property	Description
Protobuf Descriptor File	Descriptor file (.desc) to use. The descriptor file must be in the Data Collector resources directory, `$SDC_RESOURCES`. For information about generating the descriptor file, see Protobuf data format prerequisites.
Message Type	The fully-qualified name for the message type to use when reading data. Use the following format: `<package name>.<message type>`. Use a message type defined in the descriptor file.
Delimited Messages	Indicates if a message might include more than one protobuf message.
Compression Format	The compression format of the files: None - Processes only uncompressed files. Compressed File - Processes files that are compressed by the supported compression formats. Archive - Processes files that are archived by the supported archive formats. Compressed Archive - Processes files that are archived and compressed by the supported archive and compression formats.
File Name Pattern within Compressed Directory	For archive and compressed archive files, file name pattern that represents the files to process within the compressed directory. You can use UNIX-style wildcards, such as an asterisk or question mark. For example, .json. Default is , which processes all files.

For SDC Record data, on the Data Format tab, configure the following properties:

SDC Record Property	Description
Compression Format	The compression format of the files: None - Processes only uncompressed files. Compressed File - Processes files that are compressed by the supported compression formats. Archive - Processes files that are archived by the supported archive formats. Compressed Archive - Processes files that are archived and compressed by the supported archive and compression formats.
File Name Pattern within Compressed Directory	For archive and compressed archive files, file name pattern that represents the files to process within the compressed directory. You can use UNIX-style wildcards, such as an asterisk or question mark. For example, .json. Default is , which processes all files.

For text data, on the Data Format tab, configure the following properties:

Text Property	Description
Max Line Length	Maximum number of characters allowed for a line. Longer lines are truncated. Adds a boolean field to the record to indicate if it was truncated. The field name is Truncated. This property can be limited by the Data Collector parser buffer size. For more information, see Maximum record size.
Use Custom Delimiter	Uses custom delimiters to define records instead of line breaks.
Custom Delimiter	One or more characters to use to define records.
Include Custom Delimiter	Includes delimiter characters in the record.
Charset	Character encoding of the files to be processed.
Ignore Control Characters	Removes all ASCII control characters except for the tab, line feed, and carriage return characters.

For XML data, on the Data Format tab, configure the following properties:

XML Property	Description
Delimiter Element	Delimiter to use to generate records. Omit a delimiter to treat the entire XML document as one record. Use one of the following: An XML element directly under the root element. Use the XML element name without surrounding angle brackets ( < > ) . For example, msg instead of <msg>. A simplified XPath expression that specifies the data to use. Use a simplified XPath expression to access data deeper in the XML document or data that requires a more complex access method. For more information about valid syntax, see Simplified XPath syntax.
Compression Format	The compression format of the files: None - Processes only uncompressed files. Compressed File - Processes files that are compressed by the supported compression formats. Archive - Processes files that are archived by the supported archive formats. Compressed Archive - Processes files that are archived and compressed by the supported archive and compression formats.
File Name Pattern within Compressed Directory	For archive and compressed archive files, file name pattern that represents the files to process within the compressed directory. You can use UNIX-style wildcards, such as an asterisk or question mark. For example, .json. Default is , which processes all files.
Preserve Root Element	Includes the root element in the generated records. When omitting a delimiter to generate a single record, the root element is the root element of the XML document. When specifying a delimiter to generate multiple records, the root element is the XML element specified as the delimiter element or is the last XML element in the simplified XPath expression specified as the delimiter element.
Include Field XPaths	Includes the XPath to each parsed XML element and XML attribute in field attributes. Also includes each namespace in an xmlns record header attribute. When not selected, this information is not included in the record. By default, the property is not selected.
Namespaces	Namespace prefix and URI to use when parsing the XML document. Define namespaces when the XML element being used includes a namespace prefix or when the XPath expression includes namespaces. For information about using namespaces with an XML element, see Using XML elements with namespaces. For information about using namespaces with XPath expressions, see Using XPath expressions with namespaces. Using simple or bulk edit mode, click the Add icon to add additional namespaces.
Output Field Attributes	Includes XML attributes and namespace declarations in the record as field attributes. When not selected, XML attributes and namespace declarations are included in the record as fields. By default, the property is not selected.
Max Record Length (chars)	The maximum number of characters in a record. Longer records are diverted to the flow for error handling. This property can be limited by the Data Collector parser buffer size. For more information, see Maximum record size.
Charset	Character encoding of the files to be processed.
Ignore Control Characters	Removes all ASCII control characters except for the tab, line feed, and carriage return characters.