Matlab microservice in Docker Compose

I created a microservice in MATLAB according to following how-to and it works as expected: https://de.mathworks.com/help/compiler_sdk/mps_dev_test/create-a-microservice-docker-image.html

I built a web-app, which shall use that ML-container and retrieves data from it. When I run both containers independently, communication works as expected.

I now had the plan to put them into a docker-compose and start-up my application via compose. This is the compose-file, that I currently use:

services:

web:

image: web_app:latest

ports:

- "5000:5000"

environment:

- MLSL_URI=http://mlsl:9910

mlsl:

image: mlsl_server:latest

ports:

- "9900:9910"

container_name: mlsl

I now face following issue:

• web-container cannot access the ML-container's necessary service via the internal port - I receive HTTP404
• I use following endpoint for that http://mlsl:9910/functionarchive/convertData

I tried following things:

• I checked the external endpoint of the container via http://mlsl:9900/api/health and received HTTP200
• the service of the ML-container is still accessible and I receive data via the external port
• via http://mlsl:9900/functionarchive/convertData
• I checked the internal endpoint of the internal network of the container via http://mlsl:9910/api/health and receive a HTTP403, indicating permission issues

So I am quite stuck. Is there any way to access the services inside the docker network or is it just possible to access the public docker port of the ML-container? Do I need to change the container build settings in ML/SL? I used the settings as mentioned in the how-to of ML/SL.

Answer 1

[Harsh]

Hi,

From what I can gather, you are trying to run 2 MATLAB docker images simultaneously using docker-compose and call 1 image from another.

Here's a guide on how MATLAB Docker images can interact when deployed with Docker Compose:

• In this example, two functions have been created: thisAdds and makeCalls:

function c = thisadds(a, b)
    c = a + b;
end

When specifying the connection, instead of using "localhost," the local IP address is used. This IP can be found using various methods, such as executing ifconfig (requires net-tools) on the WSL.

• These functions can be compiled using the “compiler.build.productionServerArchive” command.

(For thisadds.m)

thisAddsObj = compiler.build.productionServerArchive('thisadds.m',...
'FunctionSignatures','thisaddsFunctionSignatures.json',...
'ArchiveName','thisaddsarchive','Verbose','on')

(For makecall.m)

makecallObj = compiler.build.productionServerArchive('makecall.m',...
'FunctionSignatures','makecallFunctionSignatures.json',...
'ArchiveName','makecallarchive','Verbose','on')

Additionally, a function signature has been created for makeCalls. More information about function signatures can be found at the following link:

https://www.mathworks.com/help/compiler_sdk/mps_restfuljson/matlab-function-signatures-in-json.html

• The Docker images are created using the “compiler.package.microserviceDockerImage” function.

(To create thisadds docker image)

compiler.package.microserviceDockerImage(thisAddsObj,'ImageName','thisadds')

(To create makecall docker image)

compiler.package.microserviceDockerImage(makecallObj,'ImageName','makecall')

• Next, access the WSL to verify the creation of Docker images. The names of the images should be listed:

docker images

• Create a docker-compose.yml file to configure the setup.

Note: To change the endpoint from 9910, modifications in the MATLAB image are necessary; simply changing the port mapping from 5000:5000 will not suffice without adjustments.

• Run Docker Compose to start the services:

docker-compose up

• Finally, call the makeCalls Docker image to test the setup:

Voila, it works!!