IoT Edge Module to Module commuincation using API calls

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IoT Edge Module to Module commuincation using API calls

Dhanavath Vishnu 366

Hi Community,

we are developing an IoT edge device, which is having multiple modules run, in that one-off is Backend API module(module1) and another one is front end angular module (module2). The Backend API module host multiple API's , those will be query by the front-end module. What is the best messaging routing mechanism, I can use in this scenario on IoT Edge runtime?

However, I have tried API call by module name from module 2 to module 1 Ex: http://module1:80/api, but I am not getting the expected output, the frontend module showing empty output data.

Is this the right method to do so? any suggestions are welcome, thanks your valuable time.

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Sander van de Velde | MVP 36,756 MVP Volunteer Moderator

Hello @Dhanavath Vishnu ,

I understand you want to communicate from the non-azure-iot-edge module (running an angular website) to another module being part of the regular Azure IoT edge routing mechanism.

Instead of trying to connect to these inputs (being secured using TLS communication and only trusting known modules), I suggest a number of solutions that are easier to manage and simpler from architecture:

Expose an eg. SignalR / Websocket endpoint on the angular module and let the IoT edge custom module connect as a client and act as bridge
Let the iot edge custom module expose an eg. signal-R / WebSockets / MQTT / HTTP / UDP protocol server and let it act as bridge
- Try to build your Angular website module and create a Module client based on one of the Azure IoT Edge SDKs and route directly (you do not need a second module)
- Your angular module could behave like a child Azure IoT device.

Using these possible solutions, you bridge two worlds (separation of concerns) and you are in full control of the security needed for this.

If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.

Dhanavath Vishnu 366 Reputation points

2022-12-12T04:38:54.927+00:00

Hi @Sander van de Velde | MVP ,

Thanks for your quick response, I have tried to expose the custom module (module1) TCP port by mentioning it as explicitly in docker file (EXPOSE 80).

Two ways I have tested the working of this solution with the mentioned method of exposing http protocol.

In Method 1:
Module 1 hosted on the IoT Edge VM, using host config - port binding option, I have bind the 80/tcp with 8080 of VM host. By using DNSname:8080, I am able to access the API's using swagger UI, the same URL is integrated with in front end angular code. In this case the angular module is containerized and hosted on ACI (Azure Container Instance), by accessing the DNS of ACI, running that URL on the web browser I am able to get the expected output on front end UI.

API Integration URL: "http://DNS Name of IoT Edge VM:9090/api/users"
UI URL: http://ACI DNS Name/api/users

In Method 2:
Module 1 and Module 2 (Angular module, dockerize container), both hosted on IoT Edge VM, this time port binding done for module 2, to see the Web UI on the browser. For the API integration I have used the module 1 name in the http API call from module 2. This time on the web browser, I am able to see the frontend UI, but there is no data present. It seems that module 2 is not able to do API call to module 1 on IoT edge environment.

API Integration URL = "http://module1:80/api/users" //module name is used
UI URL: http://DNS Name of IoT Edge VM:8080/users

Need your input on the same, Thanks...

Sander van de Velde | MVP 36,756 MVP Volunteer Moderator

Hello

If you want to expose a website as a docker container, you need to adjust the deployment manifest.

Check out this blog post on how to expose a Blazor web app:

"bl": {  
  "settings": {  
    "image": "svelde/blazorclientmodule:20200502143131",  
    "createOptions": "{\"HostConfig\":{\"PortBindings\":{\"443/tcp\":[{\"HostPort\":\"6443\"}],\"80/tcp\":[{\"HostPort\":\"6080\"}]}}}"  
                        },  
  "type": "docker",  
  "version": "1.0",  
  "status": "running",  
  "restartPolicy": "always"  
},

Dhanavath Vishnu 366 Reputation points

2022-12-12T10:23:48.21+00:00

Hi @Sander van de Velde | MVP ,

Yes, I have exposed same way for my angular module container (modue2: front end), using the DNS name of host and its port I can be able to see the application running and the UI functionalist are working, but not able to get the data from another module (module1: Backend API) which is hosted on the IoT Edge environment. In my case I am not using any routes, I am directly doing an API call from module 2 to module 1 by exposing container ports.

My question is, without routes definition, can two modules (one is custom IoT edge & another one is non-IoT edge just a container with angular code) communicates on IoT Edge environment? Just by using simple HTTP API calls?

Thank you for your valuable time @Sander van de Velde | MVP
Sander van de Velde | MVP 36,756 Reputation points MVP Volunteer Moderator

2022-12-12T21:29:21.95+00:00

Hello @Dhanavath Vishnu ,

yes, docker containers are just acting as applications. So, if the modules expose public endpoints, these are accessible.

I do not recommend running docker containers on the same edge device OUTSIDE the deployment manifest.

Yes, you can host every kind of container using Azure IoT Edge (eg. Grafana, InfluxDB) and you miss the opportunity to control every single module/container from the cloud.

Please take a look at my blog where I demonstrate various combinations of IoT Edge supporting containers and non-iot-edge modules.

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IoT Edge Module to Module commuincation using API calls

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