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92 lines
3.5 KiB
Markdown
92 lines
3.5 KiB
Markdown
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---
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title: Build a Connector
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slug: /sdk/python/build-connector
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---
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# Build a Connector
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This design doc will walk through developing a connector for OpenMetadata
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Ingestion is a simple python framework to ingest the metadata from various sources.
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Please look at our framework [APIs](https://github.com/open-metadata/OpenMetadata/tree/main/ingestion/src/metadata/ingestion/api).
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## Workflow
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[workflow](https://github.com/open-metadata/OpenMetadata/blob/main/ingestion/src/metadata/ingestion/api/workflow.py) is a simple orchestration job that runs the components in an Order.
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A workflow consists of [Source](/sdk/python/build-connector/source) and [Sink](/sdk/python/build-connector/sink). It also provides support for [Stage](/sdk/python/build-connector/stage) and [BulkSink](/sdk/python/build-connector/bulk-sink).
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Workflow execution happens in a serial fashion.
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1. The **Workflow** runs the **source** component first. The **source** retrieves a record from external sources and emits the record downstream.
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2. If the **processor** component is configured, the **workflow** sends the record to the **processor** next.
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3. There can be multiple **processor** components attached to the **workflow**. The **workflow** passes a record to each **processor** in the order they are configured.
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4. Once a **processor** is finished, it sends the modified record to the **sink**.
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5. The above steps are repeated for each record emitted from the **source**.
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In the cases where we need aggregation over the records, we can use the **stage** to write to a file or other store. Use the file written to in **stage** and pass it to **bulk sink** to publish to external services such as **OpenMetadata** or **Elasticsearch**.
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Each `Step` comes from this generic definition:
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```python
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class Step(ABC, Closeable):
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"""All Workflow steps must inherit this base class."""
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status: Status
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def __init__(self):
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self.status = Status()
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@classmethod
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@abstractmethod
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def create(cls, config_dict: dict, metadata: OpenMetadata) -> "Step":
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pass
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def get_status(self) -> Status:
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return self.status
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@abstractmethod
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def close(self) -> None:
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pass
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```
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so we always need to inform the methods:
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- `create` to initialize the actual step.
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- `close` in case there's any connection that needs to be terminated.
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On top of this, you can find further notes on each specific step in the links below:
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{% inlineCalloutContainer %}
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{% inlineCallout
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color="violet-70"
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icon="source"
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bold="Source"
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href="/sdk/python/build-connector/source" %}
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The connector to external systems which outputs a record for downstream to process.
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{% /inlineCallout %}
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{% inlineCallout
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color="violet-70"
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icon="filter_alt"
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bold="Sink"
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href="/sdk/python/build-connector/sink" %}
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It will get the event emitted by the source, one at a time.
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{% /inlineCallout %}
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{% inlineCallout
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color="violet-70"
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icon="storage"
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bold="Stage"
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href="/sdk/python/build-connector/stage" %}
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It can be used to store the records or to aggregate the work done by a processor.
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{% /inlineCallout %}
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{% inlineCallout
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color="violet-70"
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icon="filter_list"
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bold="BulkSink"
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href="/sdk/python/build-connector/bulk-sink" %}
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It can be used to bulk update the records generated in a workflow.
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{% /inlineCallout %}
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{% /inlineCalloutContainer %}
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Read more about the Workflow management [here](https://github.com/open-metadata/OpenMetadata/blob/main/ingestion/src/metadata/workflow/README.md).
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