rpk topic produce

Text and numbers can be formatted in many different ways, and the default format can be changed within brace modifiers. %v prints a value, while %v{hex} prints the value hex encoded. %T prints the length of a topic in ASCII, while %T{big8} prints the length of the topic as an eight byte big endian.

All modifiers go within braces following a percent-escape.

Formatting number values can have the following modifiers:

All numbers are truncated as necessary per the modifier. Printing %V{byte} for a length 256 value prints a single null, whereas printing %V{big8} prints the bytes 1 and 0.

When writing number sizes, the size corresponds to the size of the raw values, not the size of encoded values. %T% t{hex} for the topic foo prints 3 666f6f, not 6 666f6f.

By default, the timestamp field is printed as a millisecond number value. In addition to the number modifiers above, timestamps can be printed with either Go formatting:

Or strftime formatting:

An arbitrary amount of brackets (or braces, or # symbols) can wrap your date formatting:

This prints [YYYY-MM-DD], while the surrounding three # on each side are used to wrap the formatting.

For more information on Go time formatting, see the Go documentation.

For more information on strftime formatting, run man strftime.

Records can be encoded using a specified schema from your schema registry. Use the --schema-id or --schema-key-id flags to define the schema ID, and rpk will retrieve the schemas and encode the record accordingly.

Additionally, using topic in these flags allows for the use of the Topic Name Strategy. This strategy identifies a schema subject name based on the topic itself. For example:

Produce to foo, encode using the latest schema in the subject foo-value:

For protobuf schemas, you can specify the fully qualified name of the message you want the record to be encoded with. Use the --schema-type flag or --schema-key-type. If the schema contains only one message, specifying the message name is unnecessary. For example:

Produce to foo, using schema ID 1, message FQN Person.Name:

By default, records produced without a value will have an empty-string value, "". The below example produces a record with the key not_a_tombstone_record and the value "":

Tombstone records (records with a null value) can be produced by using the -Z flag and creating empty-string value records. Using the same example from above, but adding the -Z flag will produce a record with the key tombstone_record and the value null:

Records produced with values of string "null" are not considered tombstones by Redpanda.

Producing requires a topic to produce to. The topic can be specified either directly as an argument, or in the input text through %t. A parsed topic takes precedence over the default passed in topic. If no topic is specified directly and no topic is parsed, this command will quit with an error.

The input format can parse partitions to produce directly to with %p. Doing so requires specifying a non-negative --partition flag. Any parsed partition takes precedence over the --partition flag; specifying the flag is the main requirement for being able to directly control which partition to produce to.

You can also specify an output format to write when a record is produced successfully. The output format follows the same formatting rules as the topic consume command. See that command’s help text for a detailed description.

A key and value, separated by a space and ending in newline

A four byte topic, four byte key, and four byte value

A value to a specific partition (requires non-negative --partition flag)

A big-endian uint16 key size, the text " foo ", and then that key

A value that can be two or three characters followed by a newline

A key and a JSON value, separated by a space