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gcp_pubsub

Sends messages to a GCP Cloud Pub/Sub topic. Metadata from messages are sent as attributes.

# Common config fields, showing default values
output:
  label: ""
  gcp_pubsub:
    project: "" # No default (required)
    topic: "" # No default (required)
    endpoint: ""
    max_in_flight: 64
    count_threshold: 100
    delay_threshold: 10ms
    byte_threshold: 1000000
    metadata:
      exclude_prefixes: []
    batching:
      count: 0
      byte_size: 0
      period: ""
      jitter: 0
      check: ""

For information on how to set up credentials check out this guide.

Troubleshooting​

If you're consistently seeing Failed to send message to gcp_pubsub: context deadline exceeded error logs without any further information it is possible that you are encountering https://github.com/warpstreamlabs/bento/issues/1042, which occurs when metadata values contain characters that are not valid utf-8. This can frequently occur when consuming from Kafka as the key metadata field may be populated with an arbitrary binary value, but this issue is not exclusive to Kafka.

If you are blocked by this issue then a work around is to delete either the specific problematic keys:

pipeline:
  processors:
    - mapping: |
        meta kafka_key = deleted()

Or delete all keys with:

pipeline:
  processors:
    - mapping: meta = deleted()

Fields​

project​

The project ID of the topic to publish to.

Type: string

topic​

The topic to publish to. This field supports interpolation functions.

Type: string

endpoint​

An optional endpoint to override the default of pubsub.googleapis.com:443. This can be used to connect to a region specific pubsub endpoint. For a list of valid values check out this document.

Type: string
Default: ""

# Examples

endpoint: us-central1-pubsub.googleapis.com:443

endpoint: us-west3-pubsub.googleapis.com:443

ordering_key​

The ordering key to use for publishing messages. This field supports interpolation functions.

Type: string

max_in_flight​

The maximum number of messages to have in flight at a given time. Increasing this may improve throughput.

Type: int
Default: 64

count_threshold​

Publish a pubsub buffer when it has this many messages

Type: int
Default: 100

delay_threshold​

Publish a non-empty pubsub buffer after this delay has passed.

Type: string
Default: "10ms"

byte_threshold​

Publish a batch when its size in bytes reaches this value.

Type: int
Default: 1000000

publish_timeout​

The maximum length of time to wait before abandoning a publish attempt for a message.

Type: string
Default: "1m0s"

# Examples

publish_timeout: 10s

publish_timeout: 5m

publish_timeout: 60m

metadata​

Specify criteria for which metadata values are sent as attributes, all are sent by default.

Type: object

metadata.exclude_prefixes​

Provide a list of explicit metadata key prefixes to be excluded when adding metadata to sent messages.

Type: array
Default: []

flow_control​

For a given topic, configures the PubSub client's internal buffer for messages to be published.

Type: object

flow_control.max_outstanding_bytes​

Maximum size of buffered messages to be published. If less than or equal to zero, this is disabled.

Type: int
Default: -1

flow_control.max_outstanding_messages​

Maximum number of buffered messages to be published. If less than or equal to zero, this is disabled.

Type: int
Default: 1000

flow_control.limit_exceeded_behavior​

Configures the behavior when trying to publish additional messages while the flow controller is full. The available options are block (default), ignore (disable), and signal_error (publish results will return an error).

Type: string
Default: "block"
Options: ignore, block, signal_error.

batching​

Configures a batching policy on this output. While the PubSub client maintains its own internal buffering mechanism, preparing larger batches of messages can further trade-off some latency for throughput.

Type: object

# Examples

batching:
  byte_size: 5000
  count: 0
  period: 1s

batching:
  count: 10
  period: 1s

batching:
  check: this.contains("END BATCH")
  count: 0
  period: 1m

batching:
  count: 10
  jitter: 0.1
  period: 10s

batching.count​

A number of messages at which the batch should be flushed. If 0 disables count based batching.

Type: int
Default: 0

batching.byte_size​

An amount of bytes at which the batch should be flushed. If 0 disables size based batching.

Type: int
Default: 0

batching.period​

A period in which an incomplete batch should be flushed regardless of its size.

Type: string
Default: ""

# Examples

period: 1s

period: 1m

period: 500ms

batching.jitter​

A non-negative factor that adds random delay to batch flush intervals, where delay is determined uniformly at random between 0 and jitter * period. For example, with period: 100ms and jitter: 0.1, each flush will be delayed by a random duration between 0-10ms.

Type: float
Default: 0

# Examples

jitter: 0.01

jitter: 0.1

jitter: 1

batching.check​

A Bloblang query that should return a boolean value indicating whether a message should end a batch.

Type: string
Default: ""

# Examples

check: this.type == "end_of_transaction"

batching.processors​

A list of processors to apply to a batch as it is flushed. This allows you to aggregate and archive the batch however you see fit. Please note that all resulting messages are flushed as a single batch, therefore splitting the batch into smaller batches using these processors is a no-op.

Type: array

# Examples

processors:
  - archive:
      format: concatenate

processors:
  - archive:
      format: lines

processors:
  - archive:
      format: json_array