python(feat): add MCAP imports

python/CHANGELOG.md

@@ -5,6 +5,29 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### What's New
+
+#### MCAP imports
+
+`client.data_import` now supports MCAP (`.mcap`) files with ROS 2 (`ros2msg`/`cdr`) topics.
+
+```python
+job = client.data_import.import_from_path("recording.mcap", asset=my_asset)
+```
+
+Importing without a config ingests every supported channel. Topics that cannot be decoded fail the import unless `McapParseErrorPolicy.IGNORE_ERROR` is set.
+
+`detect_config` reads the file's channels locally without decoding messages, returning an `McapImportConfig` whose `data` holds one entry per field. Edit it to select, rename, or retype channels before importing.
+
+```python
+config = client.data_import.detect_config("recording.mcap")
+config.complex_types_import_mode = McapComplexTypesImportMode.STRING
+```
+
+Variable-cardinality fields (dynamic and bounded arrays) are typed `BYTES`. As with Parquet, `complex_types_import_mode` on the config decides what each becomes: Arrow IPC bytes, a JSON string under `<name>.json`, both (the default), or neither.
+
+Reading a file locally needs the new `mcap` extra (`pip install sift-stack-py[mcap]`), so both `detect_config` and importing without a config require it.
+
 ## [v0.20.0] - August 25, 2026
 
 ### What's New

python/docs/guides/pytest_plugin/index.md

@@ -100,11 +100,11 @@ The plugin runs in one of three modes, picked at invocation.
 | **Offline** | `--sift-offline` | No; records to a log file for later replay | Environments without Sift access.                             |
 | **Disabled** | `--sift-disabled` | No | Local dev. Bounds still evaluate and return a real pass/fail. |
 
-Online mode pings Sift once at session start and aborts if Sift is unreachable or the credentials are invalid, 
-so a misconfigured job fails immediately instead of silently producing no report. 
-During the run, every create and update is appended to a JSONL log file. 
-A background worker uploads new entries to Sift incrementally. 
-If the connection drops mid-test, the test keeps running and the log keeps writing locally. 
+Online mode pings Sift once at session start and aborts if Sift is unreachable or the credentials are invalid,
+so a misconfigured job fails immediately instead of silently producing no report.
+During the run, every create and update is appended to a JSONL log file.
+A background worker uploads new entries to Sift incrementally.
+If the connection drops mid-test, the test keeps running and the log keeps writing locally.
 The remaining entries can be uploaded afterward by running import-test-result-log, which the plugin prints on exit. That command resumes into the report the interrupted run created rather than starting a second one.
 
 See [Running Modes](running_modes.md) for the log-file and replay pipeline,

python/examples/data_import/mcap/main.py

@@ -0,0 +1,79 @@
+"""Import an MCAP (.mcap) file into Sift.
+
+MCAP files are self-describing, so the import needs no column mapping: every
+channel of every supported topic (ros2msg schemas with cdr messages) is
+imported. Channel names combine the topic and flattened field path; the
+bundled sample_data.mcap produces "/imu/data.angular_velocity.x",
+"/imu/data.linear_acceleration.x", "/battery.voltage", and their siblings.
+
+Swap sample_data.mcap for your own .mcap recording.
+"""
+
+import os
+
+from dotenv import load_dotenv
+from sift_client import SiftClient
+
+if __name__ == "__main__":
+    load_dotenv()
+
+    grpc_uri = os.getenv("SIFT_GRPC_URI")
+    assert grpc_uri, "expected 'SIFT_GRPC_URI' environment variable to be set"
+
+    rest_uri = os.getenv("SIFT_REST_URI")
+    assert rest_uri, "expected 'SIFT_REST_URI' environment variable to be set"
+
+    apikey = os.getenv("SIFT_API_KEY")
+    assert apikey, "expected 'SIFT_API_KEY' environment variable to be set"
+
+    asset_name = os.getenv("ASSET_NAME")
+    assert asset_name, "expected 'ASSET_NAME' environment variable to be set"
+
+    client = SiftClient(api_key=apikey, grpc_url=grpc_uri, rest_url=rest_uri)
+
+    # Auto-detect the config and import the file.
+    import_job = client.data_import.import_from_path(
+        "sample_data.mcap",
+        asset=asset_name,
+    )
+
+    import_job.wait_until_complete()
+
+    # If auto-detect doesn't quite match your file, inspect the config and patch
+    # it before importing. Common fixes: drop channels you don't need, rename or
+    # retype a channel, skip undecodable topics, set a start time for logs on a
+    # non-Unix epoch, or pick metadata records to import.
+    #
+    # from datetime import datetime, timezone
+    #
+    # from sift_client.sift_types.data_import import (
+    #     McapComplexTypesImportMode,
+    #     McapParseErrorPolicy,
+    # )
+    #
+    # config = client.data_import.detect_config("sample_data.mcap")
+    # print(config)  # inspect every detected channel
+    #
+    # # Example: import array fields only as JSON strings, instead of the
+    # # default of both JSON and Arrow IPC bytes
+    # config.complex_types_import_mode = McapComplexTypesImportMode.STRING
+    #
+    # # Example: import only the IMU topic
+    # config.data = [d for d in config.data if d.topic == "/imu/data"]
+    #
+    # # Example: skip undecodable topics and records instead of failing
+    # config.parse_error_policy = McapParseErrorPolicy.IGNORE_ERROR
+    #
+    # # Example: reinterpret log_time as elapsed nanoseconds from an explicit
+    # # start; only for recorders whose clock did not track Unix time
+    # config.relative_start_time = datetime(2026, 1, 1, tzinfo=timezone.utc)
+    #
+    # # Example: import every key of a named metadata record as run metadata
+    # config.metadata_records = ["calibration"]
+    #
+    # import_job = client.data_import.import_from_path(
+    #     "sample_data.mcap",
+    #     asset=asset_name,
+    #     config=config,
+    # )
+    # import_job.wait_until_complete()

python/examples/data_import/mcap/requirements.txt

@@ -0,0 +1,2 @@
+python-dotenv
+sift-stack-py[mcap]

python/lib/sift_client/_internal/low_level_wrappers/data_imports.py

@@ -17,6 +17,7 @@
     CsvImportConfig,
     Hdf5ImportConfig,
     ImportConfig,
+    McapImportConfig,
     ParquetFlatDatasetImportConfig,
     ParquetSingleChannelPerRowImportConfig,
     TdmsImportConfig,
@@ -47,6 +48,8 @@ def _set_config_on_request(
         request.hdf5_config.CopyFrom(config._to_proto())
     elif isinstance(config, UlogImportConfig):
         request.ulog_config.CopyFrom(config._to_proto())
+    elif isinstance(config, McapImportConfig):
+        request.mcap_config.CopyFrom(config._to_proto())
     else:
         raise TypeError(f"Unsupported import config type: {type(config).__name__}")