Google Cloud Platform PubSub Business Hosts

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Linked documentation to GitHub


Interoperability components for receiving or publishing Google Cloud Platform PubSub messages


This project provides example interoperability components to receive messages from and publish messages to Google Cloud Provider (GCP) PubSub topics. It uses PEX and the GCP Java libraries to connect to GCP PubSub.

For more information:


GCP PubSub


Java PEX Inbound Adapter for the IRIS business service PEX.GCP.PubSub.Service.cls. Receives messages for a GCP PubSub subscription using GCP Java libraries and sends them to the Business Service's OnProcessInput() method as a PEX.GCP.PubSub.Msg.Message.


IRIS business service. Receives and processes PEX.GCP.PubSub.Msg.Message messages from PEX.GCP.PubSub.InboundAdapter and sends them to one or more other IRIS Business Hosts.

Java PEX Outbound Adapter for the IRIS business operation PEX.GCP.PubSub.Operation. Receives PEX.GCP.PubSub.Msg.Message messages from other business hosts in IRIS and uses GCP Java libraries to publish them to a GCP PubSub topic.


IRIS business operation. Receives PEX.GCP.PubSub.Msg.Message messages from other IRIS Business Hosts and sends them to PEX.GCP.PubSub.OutboundAdapter for publishing to a GCP PubSub topic. The operation will return a PEX.GCP.Msg.PublishResponse containing the message ID assigned by GCP PubSub.


IRIS message class for GCP PubSub messages. Message data is stored in one of two %Stream properties (depending on message encoding) -- use GetDataStream() to retrieve the appropriate stream. See GCP PubSub documentation for more information about Attributes, OrderingKey, PublishTime, and MessageID.

IsBinary indicates if message is encoded as text or binary. The InboundAdapter will set IsBinary based on the Remote Setting GCPTopicEncoding. When sending a message to the OutboundAdapter, set this to true (1) when sending to topics that are configured with an Encoding of BINARY in the GCP Topic configuration.

Making use of the components


  1. This currently works with IRIS 2020.1 and greater

  2. Download the "deployment" folder from GitHub

  3. Import the included ObjectScript classes from classes.xml in the "objectscript" subfolder into the namespace containing the interoperability production

  4. Copy the included Java JAR files from the "jar" subfolder to the server: GCPPubSub.jar and the libraries folder

Adding a Business Service to the Production

  1. Add a Business Service using the class EnsLib.JavaGateway.Service to the Production or use an existing EnsLib.JavaGateway.Service.
    If it doesn't already have them, add intersystems-gateway-x.y.z.jar and intersystems-jdbc-x.y.z.jar to Additional Settings/Class Path. These JARs can be found under <IRIS installation directory>/dev/java/lib/JDK18

  2. Add a Business Service using the class PEX.GCP.PubSub.Service

Configure settings for the PubSub service

  1. Under Basic Settings, configure TargetConfigNames to send to one or more Business Hosts.

  2. Under Remote InboundAdapter:

    • Set Remote Classname to the name of the Inbound Adapter Java class: PEX.GCP.PubSub.InboundAdapter

    • Set Gateway Host and Gateway Port to those used by the EnsLib.JavaGateway.Service that was configured earlier

    • To Gateway Extra CLASSPATH, add references to the JAR files that were copied to the server. Note that if you expect to have multiple GCP services and/or operations in the production you can add these JAR references to the EnsLib.JavaGateway.Service Class Path instead:

      • GCPPubSub.jar

      • JARs found in the library folder. To save time, you can copy this from the included file classpath.txt -- note that you will need to first edit the entries in classpath.txt to point to the directory where you placed the library folder.

    • Configure Remote Settings. This is a free text field, and should contain multiple Key=Value entries, one per line.

      For an explanation of the available options, view the class documentation for PEX.GCP.PubSub.Service. The critical items are:

      • GCPCredentials

      • GCPProjectID

      • GCPSubscriptionID

Adding a Business Operation to the Production

A GCP PEX Business Operation is configured similarly to a Business Service.

Sending a message to a GCP PubSub topic

  • Construct a PEX.GCP.PubSub.Msg.Message

  • Set IsBinary to 1 for binary content or leave it at the default of 0 for JSON or text

  • Populate the data stream using GetDataStream().Write() or another stream method

  • Populate attributes

  • Populate OrderingKey if needed

  • Send the message to the GCP PubSub Business Operation

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InterSystems IRIS for Health
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