Topics

Number of chunks to store on disk for the topic. This decides the total size of the topic. Each chunk is 1 MB. When chunk num-chunks + 1 is needed, chunk 1 is discarded, etc.

The name of the topic

Integer deciding how many replicas to create for a topic. Always use an odd number. A majority of replicas is required for a topic to be operational.

• disk
• ram

disk means the topic is persistent on the host where it was originally placed at creation time. If ram is used, replication-factor is implicitly 1.

Include the host handling the request in the replication set. For topics with replication-factor 1, this means that the host handling the request is guaranteed to become the topic handler and the topic can never be moved to another host. For topics with higher replication factors, the host handling the request will be part of the initial replication set as long as its maintenance-mode is not set to out-of-service, but the topic can be moved to other hosts later as needed.

• string: The message payload is a string.
• json: The message payload is an arbitrary json object.

The format of messages on this topic.

Number of days to keep messages on this topic. If not set, messages will be kept until the topic is full.

• signature
• full

Valid when: not(../persistence) or (../persistence = 'disk')

Messages can be encrypted or cryptograhically signed when written to disk.

Number of chunks to store on disk for the topic. This decides the total size of the topic. Each chunk is 1 MB. When chunk num-chunks + 1 is needed, chunk 1 is discarded, etc.

• beginning: Start consuming from the beginning of the stream. If the topic has wrapped, i.e., started to drop chunks, the first message will be the oldest one remaining on the topic.
• end: Start consuming from the end of the stream
• unread: Start consuming from last acked message plus one

Indicates where to start consuming in the topic stream

If topic-tag is set, only messages produced with the same topic-tag will be received by this consumer. This can be useful when multiple applications need to share the same topic of infra.

Consume only messages that match this Perl RE pattern, and just skip all other messages.

Must have the value true.

Invert the match provided by the re-match pattern

A string that matches:

expr = term \*( ',' term )
term = path \*( '/' '[' expr ']' )
path = field-name [ '/' path ]
field-name = identifier / identifier '=' identifier

For example:

• fields=foo,bar - selects the fields foo and bar
• fields=foo/bar - selects the fields bar in foo
• fields=foo/[bar,baz] - selects bar and baz in foo
• fields=foo=x - selects foo, and renames foo to x in the output

Volga can trim incoming messages, delivering only the fields given here.

In follow mode, the client will continue to consume, although the last message in the topic has been delivered. By default the client will receive a socket close when the topic has been exhausted.

By default, a REST consumer will receive JSON structs, with sequence number and more. With this option, only the payload is delivered. This option is useful when viewing plain text logs.

Receive messages regardless of filters such as topic-tags and destination sites. This is sometime useful for debugging