@NABIL MHENNI Thanks for reaching out. Unfortunately right now there are no connector for GCP PubSub and no plan of supporting it. Feel free to create the feature request here if this is something you want to see as the logic app connector.
The workaround would be creating your own connectorif there are any API's or open api definition that you can leverage in the custom connector. Similarly if there are any REST API from GCP PubSub end then you can leverage those using the Native HTTP connector in your workflow.
Feel free to get back to me if you have any queries or concerns.
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