-spec debug(pid(), print | string() | none) -> ok.

Enable/disable debugging on the consumer process.

debug(Pid, print) prints debug info to stdout.

-spec start_link(pid() | brod:bootstrap(), topic(), partition(), config()) ->
              {ok, pid()} | {error, any()}.

Equivalent to start_link(ClientPid, Topic, Partition, Config, []).

-spec start_link(pid() | brod:bootstrap(), topic(), partition(), config(), [any()]) ->
              {ok, pid()} | {error, any()}.

Start (link) a partition consumer.

• min_bytes (optional, default = 0)

  Minimal bytes to fetch in a batch of messages

• max_bytes (optional, default = 1MB)

  Maximum bytes to fetch in a batch of messages.

  NOTE: this value might be expanded to retry when it is not enough to fetch even a single message, then slowly shrunk back to the given value.

• max_wait_time (optional, default = 10000 ms)

  Max number of seconds allowed for the broker to collect min_bytes of messages in fetch response

• sleep_timeout (optional, default = 1000 ms)

  Allow consumer process to sleep this amount of ms if kafka replied 'empty' message set.

• prefetch_count (optional, default = 10)

  The window size (number of messages) allowed to fetch-ahead.

• prefetch_bytes (optional, default = 100KB)

  The total number of bytes allowed to fetch-ahead. brod_consumer is greed, it only stops fetching more messages in when number of unacked messages has exceeded prefetch_count AND the unacked total volume has exceeded prefetch_bytes

• begin_offset (optional, default = latest)

  The offset from which to begin fetch requests. A subscriber may consume and process messages, then persist the associated offset to a persistent storage, then start (or restart) from last_processed_offset + 1 as the begin_offset to proceed. The offset has to already exist at the time of calling.

• offset_reset_policy (optional, default = reset_by_subscriber)

  How to reset begin_offset if OffsetOutOfRange exception is received.

  reset_by_subscriber: consumer is suspended (is_suspended=true in state) and wait for subscriber to re-subscribe with a new begin_offset option.

  reset_to_earliest: consume from the earliest offset.

  reset_to_latest: consume from the last available offset.

• size_stat_window: (optional, default = 5)

  The moving-average window size to calculate average message size. Average message size is used to shrink max_bytes in fetch requests after it has been expanded to fetch a large message. Use 0 to immediately shrink back to original max_bytes from config. A size estimation allows users to set a relatively small max_bytes, then let it dynamically adjust to a number around PrefetchCount * AverageSize

• isolation_level: (optional, default = read_commited)

  Level to control what transaction records are exposed to the consumer. Two values are allowed, read_uncommitted to retrieve all records, independently on the transaction outcome (if any), and read_committed to get only the records from committed transactions

-spec subscribe(pid(), pid(), config()) -> ok | {error, any()}.

Subscribe or resubscribe on messages from a partition.

Caller may specify a set of options extending consumer config. It is possible to update parameters such as max_bytes and max_wait_time, or the starting point (begin_offset) of the data stream. Note that you currently cannot update isolation_level.