morpheus.stages.input.databricks_deltalake_source_stage.DataBricksDeltaLakeSourceStage

class DataBricksDeltaLakeSourceStage(config, spark_query=None, items_per_page=1000, databricks_host=None, databricks_token=None, databricks_cluster_id=None)[source]

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

Source stage used to load messages from a DeltaLake table.

Parameters
config

Pipeline configuration instance.

spark_query

SQL Query that need to be executed to fetch the results from deltalake table.

items_per_page: int, default 1000

Number of rows per iteration/page to be fetched from remote spark cluster.

databricks_host

URL of Databricks host to connect to.

databricks_token

Access token for Databricks cluster.

databricks_cluster_id

Databricks cluster to be used to query the data as per SQL provided.

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[, do_propagate]) Build this stage.
can_build([check_ports]) Determines if all inputs have been built allowing this node to be built.
can_pre_build([check_ports]) Determines if all inputs have been built allowing this node to be built.
compute_schema(schema) Compute the schema for this stage based on the incoming schema from upstream stages.
get_all_input_stages() Get all input stages to this stage.
get_all_inputs() Get all input senders to this stage.
get_all_output_stages() Get all output stages from this stage.
get_all_outputs() Get all output receivers from this stage.
get_needed_columns() 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.
join() Awaitable method that stages can implement this to perform cleanup steps when pipeline is stopped.
set_needed_columns(needed_columns) Sets the columns needed to perform preallocation.
start_async() This function is called along with on_start during stage initialization.
stop() Stages can implement this to perform cleanup steps when pipeline is stopped.
supports_cpp_node() Specifies whether this Stage is capable of creating C++ nodes.
source_generator
_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]

Stages can implement this to perform 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.

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