Frequently Asked Questions

1. FA³ST Service does not load the AASX/JSON model

2. Resource not found ‘/shells’

3. Configuration could not be loaded

4. Certificate & SSL errors

5. CORS

6. Security with Reverse Proxy - basic authentication

FA³ST Service does not load the AASX/JSON model

If you get a validation error like:

[ERROR] Model validation failed with the following error(s):
Found 2 violation(s):
Duplicate identifier 'https://admin-shell.io/zvei/nameplate/2/0/Nameplate/Markings/Marking/ExplosionSafeties/ExplosionSafety/SpecificConditionsForUse' - identifiers must be globally unique
Duplicate identifier 'https://admin-shell.io/zvei/nameplate/2/0/Nameplate/Markings/Marking/ExplosionSafeties/ExplosionSafety/IncompleteDevice' - identifiers must be globally unique (de.fraunhofer.iosb.ilt.faaast.service.starter.ExecutionExceptionHandler)

Your model contains a modeling error which can lead to severe issues. If you wish to ignore this, you can start FA³ST Service with the --no-validation flag.

java -jar starter-{version}.jar -m example.aasx --no-validation

If the error is not specified, you are probably trying to load an older V2 model, such as provided by admin-shell-io.

[ERROR] Error loading model file

In this case, the model has to be updated to V3 with the current version of AASX Package Explorer. If the V3 model can be loaded by the AASX Package Explorer and fails to load, please submit an issue with the model here.

For testing purposes, we provide an example model here: Model

Resource not found ‘/shells’

{
	"messages": [
		{
			"messageType": "Error",
			"text": "Resource not found '/shells'",
			"code": "",
			"timestamp": "2024-08-09T10:43:16.913+00:00"
		}
	]
}

If you use the API and get a “Resource not found” message, FA³ST Service could not find an appropriate API call for your request. In many cases, providing the proper API prefix, for example /api/v3.0 and following the up-to-date SwaggerHub API, should lead to a valid result: https://faaast-service-v1.k8s.ilt-dmz.iosb.fraunhofer.de/api/v3.0/shells Keep in mind that the right HTTP method must be selected for specific calls.

Configuration could not be loaded

The most frequent issue with configuration files are inproper AAS references in the Asset Connection. For example, to connect the operation “calculate” to the asset where the calculation is done, the reference “(Submodel)https://example.com/ids/sm/7230_2111_9032_0866, (Operation)calculate” is used. It is important to have the whitespace between element and submodel and follow the exact AAS elements like “Property” or “File” Example:

{

	"assetConnections": [
		{
			"@class": "de.fraunhofer.iosb.ilt.faaast.service.assetconnection.http.HttpAssetConnection",
			"baseUrl": "http://localhost:5001",
			"operationProviders":
			{
				"(Submodel)https://example.com/ids/sm/7230_2111_9032_0866, (Operation)calculate":
				{
					"path": "/add",
					"format": "JSON",
					"template": "{\"data\":{\"input1\": ${input1}, \"input2\": ${input2}}}",
					"queries":
					{
						"result": "$.result"
					}
				}
			}
		}
	],
	// other configurations
}

Additionally, it should be checked if JSON syntax errors are present, for example with jsonchecker

Certificate & SSL errors

By default, FA³ST Service will generate a SSL certificate if none is provided. Those are self-generated certificates and can lead to security warnings in browsers and connection failures in AAS Clients. To turn off SSL, the environment variable sslEnabled can be used. It can also be supplied with the configuration JSON file in the endpoint configuration.

java -jar starter-{version}.jar -m example.aasx endpoints[0]_sslEnabled=false

This flag should only be used for testing purposes on local machines. For public services, provide valid certificates via the configuration file.

CORS

Another common issue when accessing FA³ST Service is a cross-origin resource sharing block. By default, the HTTP endpoint does not enable CORS, but it typically is required when you want to access the REST interface from any machine other than the one running FA³ST Service. The flag can be set with the HTTP endpoint configuration or via command-line:

java -jar starter-{version}.jar -m example.aasx endpoints[0]_corsEnabled=true

Security with Reverse Proxy - basic authentication

As AAS specification Part 4 Security is work-in-progress, to protect public services against unauthorized requests, basic authentication via reverse proxy can be configured. For NGINX, detailed information can be found here.

An example configuration with secret basic-auth-secret:

metadata:
name: ingress-with-auth
annotations:
nginx.ingress.kubernetes.io/auth-type: basic
nginx.ingress.kubernetes.io/auth-secret: basic-auth-secret
nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required - FA³ST'

The authentication configuration will vary based on your deployment environment.