fastiot_core_services.object_storage package

FastIoT Service to save “Object” into mongodb, see fastiot.db.mongodb_helper_fn.get_mongodb_client_from_env()

This Service is intended for saving “Object” inheriting the fastiot.core.data_models.FastIoTData, and requesting of historical object data. This Service is also designed to save one data type, for demanding saving multiple data types, you can instance multiple Services, using config file.

Your Object will be saved in Dictionary in such format, ‘yyy’ stands for the unpacked Attributes of Object:

{'_id': 'xxx', '_subject': 'xxx', '_timestamp': 'xxx', 'yyy': 'xxx', 'yyy': 'xxx}

In Order to use this Service, you must set a config file named ObjectStorageService.yaml or ObjectStorageService_1.yaml in my_deployment/config_dir, for reading ObjectStorageService_1.yaml FASTIOT_SERVICE_ID must be set.

search_index:
 - "_subject, _timestamp"
 - "_id"
collection: 'thing'
subject_name: 'thing.*'
reply_subject_name: 'objects'
enable_overwriting: false
identify_object_with:
 - "measurement_id"
 - "_timestamp"

  • search_index defines the MongoDB index to speed up the query. _subject and _timestamp are defined as compound index in the above example.

  • collection is the Mongodb Collection, which you want to store your data in

  • subject_name is the subject, where you send your data.

  • reply_subject_name: The subject this services listens for Historic Object Requests (fastiot.msg.hist.HistObjectReq)

  • enable_overwriting is a boolean flag for object overwriting

  • identify_object_with defines object fields, which define the whole object with its uniqueness The other fields will be overwritten respectively. Needed only if enable_overwriting set on true

Changed in version 0.2.101: Using subject_name to define the subject this service will respond is deprecated. Use the new field reply_subject_name instead. The old style will continue to work but throw a warning till it will be removed completely.

New in version 0.8.10:

  • Added mode for overwriting objects.

  • Added option for compound indices

You can assign the subject like following MyDataType or my_data_type, both will return you a right subject name format: v1.my_data_type.

CAUTION!: Thing will be instanced with different names. So by subscribing thing please always with a *. For understanding, you may reference to https://docs.nats.io/nats-concepts/subjects.

The other functionality for Object Storage Service is, you can make a request of the historical data stored in the MongoDB. To request the historical data, you need to instantiate fastiot.msg.hist.HistObjectReq, with subject_name ‘reply_object’. The code will look like:

hist_req_msg = HistObjectReq(dt_start=datetime(), dt_end=datetime(), limit=10, subject_name='logged_subject')
subject = hist_req_msg.get_reply_subject(name='my_set_reply_subject_name')

CAUTION! This subject_name should be the same as, which you have defined in ObjectStorageService.yaml. This request will reply to you a list of dictionaries. Then you can convert it to your own data type using fastiot.util.object_helper.parse_object_list().

Submodules

fastiot_core_services.object_storage.env module

class fastiot_core_services.object_storage.env.ObjectStorageConstants[source]
property subject

fastiot_core_services.object_storage.mongodb_handler module

fastiot_core_services.object_storage.object_storage_helper_fn module

fastiot_core_services.object_storage.object_storage_helper_fn.build_query_dict(hist_object_req)[source]

This function parses the HistObjectReq instance, and build the query dict to search data in database

Return type:

Dict

fastiot_core_services.object_storage.object_storage_service module

fastiot_core_services.object_storage.run module