gateway-hl7-listener

This is a Python service that does the following:

• Listen/receive MLLP HL7 messages from the configured port.
• Publish (NATS Publish-Subscribe mode) the received HL7 messages to the configured NATS JetStream server "Subject" (e.g., "HL7."). Note that the "Subject" is associated with a JetStream "Stream" (e.g., "HL7") and the stream's "Consumer" (e.g.,"MESSAGES").
• The published NATS messages are acknowledge by the server. If messages publishes start to fail or acknowledges do not occur, listening for HL7 messages will halt.

Development

Setup

gradle tasks # will list all the available tasks
gradle build # will setup virtualenv, run all tests, and create reports and distribution

Update gradle.properties as needed.

Adding Dependencies

Update the build.gradle file to add dependencies.

Install NATS Jetstream server and NATS CLI

You can find the instructions for the NATS Jetstream server (via docker) here: https://hub.docker.com/_/nats/

You can find the instructions for the NATS Cli here: https://github.com/nats-io/natscli

Create the HL7 stream and MESSAGES consumer

Create the HL7 stream with wildcard/unspecified subjects:

nats str add HL7 --subjects "HL7.*" --ack --max-msgs=-1 --max-bytes=-1 --max-age=1y --storage file --retention limits --max-msg-size=-1 --discard=old --max-msgs-per-subject=-1 --dupe-window=2m --replicas=1

Create the MESSAGES consumer for the HL7 stream and filter to a subject named "HL7.MESSAGES":

nats con add HL7 MESSAGES --filter HL7.MESSAGES --ack explicit --pull --deliver all --max-deliver=-1 --sample 100

Building

Use gradle to do a clean build (for Windows, "clean" is not available from PowerShell terminal):

gradle clean build 

Testing

To run unittest, execute:

gradle clean test 

Environment variables

You will need to override these if you are not running locally.

HL7_MLLP_HOST = HL7 MLLP host server

HL7_MLLP_PORT = HL7 MLLP host server port to listen for incoming HL7 messages

NATS_OUTGOING_SUBJECT = NATS subject to use

NATS_SERVER_URL = NATS Jetstream connection info

Creating the docker image

Create the container using the docker build command below. Add your artifactory id (this is likely your w3 email) and key where specified.

docker build -t gateway-hl7-listener:1.0.0 .

If the steps completed successfully, the image specified by the -t option should now exist.