Building a Python client to send OMF to PI, EDS or Cds

February 4, 2025 · View on GitHub

Version: 2.2.0

Cds Test Status	EDS Test Status	PI Test Status

The sample code in this topic demonstrates how to send OMF messages using Python to PI, Edge Data Store (EDS) or CONNECT data services (Cds).

The samples were built and tested against Python 3. If you are using a different version you might encounter errors or unexepected behavior.

To run this sample:

Clone the GitHub repository
Install required modules: pip install -r requirements.txt
Open the folder with your favorite IDE
Rename the placeholder config file appsettings.placeholder.json to appsettings.json
Update appsettings.json with the credentials for the enpoint(s) you want to send to. See Configure endpoints and authentication below for additional details
Run program.py

To test this sample:

Option 2

Install pytest pip install pytest
Run pytest program.py

This application can be customized to send your own custom types, containers, and data by modifying the OMF-Types.json OMF-Containers.json, and OMF-Data.json files respectively. Each one of these files contains an array of OMF json objects, which are created in the endpoints specified in appsettings.json when the application is run. For more information on forming OMF messages, please refer to our OMF version 1.2 documentation.

In addition to modifying the json files mentioned above, the get_data function in program.py should be updated to populate the OMF data messages specified in OMF-Data.json with data from your data source. Finally, if there are any other activities that you would like to be running continuously, this logic can be added under the while loop in the main() function of program.py.

Configure endpoints and authentication

The sample is configured using the file appsettings.placeholder.json. Before editing, rename this file to appsettings.json. This repository's .gitignore rules should prevent the file from ever being checked in to any fork or branch, to ensure credentials are not compromised.

The application can be configured to send to any number of endpoints specified in the endpoints array within appsettings.json. In addition, there are three types of endpoints: (Cds), EDS, and PI. Each of the 3 types of enpoints are configured differently and their configurations are explained in the sections below.

Cds endpoint configuration

An OMF ingress client must be configured. On our Aveva PI System Learning Channel on YouTube we have a video on Creating an OMF Connection.

The format of the configuration for a Cds endpoint is shown below along with descriptions of each parameter. Replace all parameters with appropriate values.

{
  "Selected": true,
  "EndpointType": "CDS",
  "Resource": "https://uswe.datahub.connect.aveva.com",
  "NamespaceId": "PLACEHOLDER_REPLACE_WITH_NAMESPACE_ID",
  "Tenant": "PLACEHOLDER_REPLACE_WITH_TENANT_ID",
  "clientId": "PLACEHOLDER_REPLACE_WITH_CLIENT_ID",
  "ClientSecret": "PLACEHOLDER_REPLACE_WITH_CLIENT_SECRET",
  "ApiVersion": "v1",
  "VerifySSL": true,
  "UseCompression": false,
  "WebRequestTimeoutSeconds": 30
}

Parameters	Required	Type	Description
Selected	required	boolean	Tells the application if the endpoint should be sent to
EndpointType	required	string	The endpoint type. For Cds this will always be "CDS"
Resource	required	string	The endpoint for the Cds namespace. If the tenant/namespace is located in NA, it is https://uswe.datahub.connect.aveva.com and if in EMEA, it is https://euno.datahub.connect.aveva.com
NamespaceID	required	string	The name of the namespace in Cds that is being sent to
Tenant	required	string	The Tenant ID of the Tenant in Cds that is being sent to
ClientId	required	string	The client ID that is being used for authenticating to Cds
ClientSecret	required	string	The client secret that is being used for authenticating to Cds
ApiVersion	required	string	The API version of the Cds endpoint
VerifySSL	optional	boolean	A feature flag for verifying SSL when connecting to the Cds endpoint. By defualt this is set to true as it is strongly recommended that SSL be checked
UseCompression	optional	boolean	A feature flag for enabling compression on messages sent to the Cds endpoint
WebRequestTimeoutSeconds	optional	integer	A feature flag for changing how long it takes for a request to time out

EDS endpoint configurations

The format of the configuration for an EDS endpoint is shown below along with descriptions of each parameter. Replace all parameters with appropriate values.

{
  "Selected": true,
  "EndpointType": "EDS",
  "Resource": "http://localhost:5590",
  "ApiVersion": "v1",
  "UseCompression": false
}

Parameters	Required	Type	Description
Selected	required	boolean	Tells the application if the endpoint should be sent to
EndpointType	required	string	The endpoint type. For EDS this will always be "EDS"
Resource	required	string	The endpoint for EDS if the namespace. If EDS is being run on your local machine with the default configuration, it will be http://localhost:5590
ApiVersion	required	string	The API version of the EDS endpoint
UseCompression	optional	boolean	A feature flag for enabling compression on messages sent to the Cds endpoint
WebRequestTimeoutSeconds	optional	integer	A feature flag for changing how long it takes for a request to time out

PI endpoint configuration

The format of the configuration for a PI endpoint is shown below along with descriptions of each parameter. Replace all parameters with appropriate values.

{
  "Selected": true,
  "EndpointType": "PI",
  "Resource": "PLACEHOLDER_REPLACE_WITH_PI_WEB_API_URL",
  "DataArchiveName": "PLACEHOLDER_REPLACE_WITH_DATA_ARCHIVE_NAME",
  "Username": "PLACEHOLDER_REPLACE_WITH_USERNAME",
  "Password": "PLACEHOLDER_REPLACE_WITH_PASSWORD",
  "VerifySSL": true,
  "UseCompression": false
}

Parameters	Required	Type	Description
Selected	required	boolean	Tells the application if the endpoint should be sent to
EndpointType	required	string	The endpoint type. For PI this will always be "PI"
Resource	required	string	The URL of the PI Web API
DataArchiveName	required	string	The name of the PI Data Archive that is being sent to
Username	required	string	The username that is being used for authenticating to the PI Web API
Password	required	string	The password that is being used for authenticating to the PI Web API
VerifySSL	optional	boolean/string	A feature flag for verifying SSL when connecting to the PI Web API. Alternatively, this can specify the path to a .pem certificate file if a self-signed certificate is being used by the PI Web API. By defualt this is set to true as it is strongly recommended that SSL be checked.
UseCompression	optional	boolean	A feature flag for enabling compression on messages sent to the Cds endpoint
WebRequestTimeoutSeconds	optional	integer	A feature flag for changing how long it takes for a request to time out

For the main OMF basic samples page ReadMe
For the main OMF samples page ReadMe
For the main AVEVA samples page ReadMe