morpheus.stages.input.kafka_source_stage.KafkaSourceStage

Bases: morpheus.pipeline.preallocator_mixin.PreallocatorMixin, morpheus.pipeline.single_output_source.SingleOutputSource

Load messages from a Kafka cluster.

Parameters

c : morpheus.config.Config

Pipeline configuration instance.

bootstrap_servers

Comma-separated list of bootstrap servers. If using Kafka created via docker-compose, this can be set to ‘auto’ to automatically determine the cluster IPs and ports

input_topic

Name of the Kafka topic from which messages will be consumed. To consume from multiple topics, repeat the same option multiple times.

group_id

Specifies the name of the consumer group a Kafka consumer belongs to.

client_id

An optional identifier of the consumer.

poll_interval

Seconds that elapse between polling Kafka for new messages. Follows the pandas interval format.

disable_commit

Enabling this option will skip committing messages as they are pulled off the server. This is only useful for debugging, allowing the user to process the same messages multiple times.

disable_pre_filtering

Enabling this option will skip pre-filtering of json messages. This is only useful when inputs are known to be valid json.

auto_offset_reset : AutoOffsetReset

Sets the value for the configuration option ‘auto.offset.reset’. See the kafka documentation for more information on the effects of each value.”

stop_after: int, default = 0

Stops ingesting after emitting stop_after records (rows in the dataframe). Useful for testing. Disabled if 0

async_commits: bool, default = True

Enable commits to be performed asynchronously. Ignored if disable_commit is True.

Attributes

has_multi_input_ports

Indicates if this stage has multiple input ports.

has_multi_output_ports

Indicates if this stage has multiple output ports.

input_count

Return None for no max intput count.

input_ports

Input ports to this stage.

is_built

Indicates if this stage has been built.

is_pre_built

Indicates if this stage has been built.

name

The name of the stage.

output_ports

Output ports from this stage.

unique_name

Unique name of stage.

Methods

_build(builder, input_nodes)[source]

This function is responsible for constructing this stage’s internal mrc.SegmentObject object. The input of this function contains the returned value from the upstream stage.

The input values are the mrc.Builder for this stage and a list of parent nodes.

Parameters

builder : mrc.Builder

mrc.Builder object for the pipeline. This should be used to construct/attach the internal mrc.SegmentObject.

input_nodes : list[mrc.SegmentObject]

List containing the input mrc.SegmentObject objects.

Returns

list[mrc.SegmentObject]

List of tuples containing the output mrc.SegmentObject object from this stage.

_build_source(builder)[source]

Abstract method all derived Source classes should implement. Returns the same value as build.

Returns

mrc.SegmentObject:

The MRC node for this stage.

_build_sources(builder)[source]

Abstract method all derived Source classes should implement. Returns the same value as build.

Returns

mrc.SegmentObject:

The MRC nodes for this stage.

build(builder, do_propagate=True)[source]

Build this stage.

Parameters

builder : mrc.Builder

MRC segment for this stage.

do_propagate

Whether to propagate to build output stages, by default True.

can_build(check_ports=False)[source]

Determines if all inputs have been built allowing this node to be built.

Parameters

check_ports

Check if we can build based on the input ports, by default False.

Returns

bool

True if we can build, False otherwise.

can_pre_build(check_ports=False)[source]

Determines if all inputs have been built allowing this node to be built.

Parameters

check_ports

Check if we can build based on the input ports, by default False.

Returns

bool

True if we can build, False otherwise.

compute_schema(schema)[source]

Compute the schema for this stage based on the incoming schema from upstream stages.

Incoming schema and type information from upstream stages is available via the schema.input_schemas and schema.input_types properties.

Derived classes need to override this method, can set the output type(s) on schema by calling set_type for all output ports. For example a simple pass-thru stage might perform the following:

If the port types in upstream_schema are incompatible the stage should raise a RuntimeError.

get_all_input_stages()[source]

Get all input stages to this stage.

Returns

list[morpheus.pipeline.pipeline.StageBase]

All input stages.

get_all_inputs()[source]

Get all input senders to this stage.

Returns

list[morpheus.pipeline.pipeline.Sender]

All input senders.

get_all_output_stages()[source]

Get all output stages from this stage.

Returns

list[morpheus.pipeline.pipeline.StageBase]

All output stages.

get_all_outputs()[source]

Get all output receivers from this stage.

Returns

list[morpheus.pipeline.pipeline.Receiver]

All output receivers.

get_needed_columns()[source]

Stages which need to have columns inserted into the dataframe, should populate the self._needed_columns dictionary with mapping of column names to morpheus.common.TypeId. This will ensure that the columns are allocated and populated with null values.

property has_multi_input_ports: bool

Indicates if this stage has multiple input ports.

Returns

bool

True if stage has multiple input ports, False otherwise.

property has_multi_output_ports: bool

Indicates if this stage has multiple output ports.

Returns

bool

True if stage has multiple output ports, False otherwise.

property input_count: int

Return None for no max intput count.

property input_ports: list[morpheus.pipeline.receiver.Receiver]

Input ports to this stage.

Returns

list[morpheus.pipeline.pipeline.Receiver]

Input ports to this stage.

property is_built: bool

Indicates if this stage has been built.

Returns

bool

True if stage is built, False otherwise.

property is_pre_built: bool

Indicates if this stage has been built.

Returns

bool

True if stage is built, False otherwise.

async join()[source]

Awaitable method that stages can implement this to perform cleanup steps when pipeline is stopped. Typically this is called after stop during a graceful shutdown, but may not be called if the pipeline is terminated on its own.

property name: str

The name of the stage. Used in logging. Each derived class should override this property with a unique name.

Returns

str

Name of a stage.

property output_ports: list[morpheus.pipeline.sender.Sender]

Output ports from this stage.

Returns

list[morpheus.pipeline.pipeline.Sender]

Output ports from this stage.

set_needed_columns(needed_columns)[source]

Sets the columns needed to perform preallocation. This should only be called by the Pipeline at build time. The needed_columns shoudl contain the entire set of columns needed by any other stage in this segment.

async start_async()[source]

This function is called along with on_start during stage initialization. Allows stages to utilize the asyncio loop if needed.

stop()[source]

Performs cleanup steps when pipeline is stopped.

supports_cpp_node()[source]

Specifies whether this Stage is capable of creating C++ nodes. During the build phase, this value will be combined with CppConfig.get_should_use_cpp() to determine whether or not a C++ node is created. This is an instance method to allow runtime decisions and derived classes to override base implementations.

property unique_name: str

Unique name of stage. Generated by appending stage id to stage name.

Returns

str

Unique name of stage.