Database names should be DNS Subdomain Names

[MarieSaphira]

Since the names of the databases defined in the ML model are used for service discovery (see here), they have to be valid in Kubernetes. The services in Kubernetes require a name that can be used as a DNS subdomain name (see here), i.e.

• contain no more than 253 characters
• contain only lowercase alphanumeric characters, ‘-’ or ‘.’
• start with an alphanumeric character
• end with an alphanumeric character

We tried adding

terminal DNS_NAME:
	('a'..'z'|'0'..'9') ('a'..'z'|'A'..'Z'|'0'..'9'|'.'|'-')* ('a'..'z'|'0'..'9')
;

to the grammar but it produces conflicts with ID. Another way would be to put this in validation (e.g. here). What is your opinion? It would be nice to have the same solution in DL and ML.

[MarieSaphira]

After discussing with @DavyLandman another possibility is to use the ML-database names for the DL-databases and for the container names all invalid characters get replaced. The API sends both values to QL

            "host": <containerName>,
            "dbName": <databaseName>

right @OrfenCLMS ?

[Bitico]

@MarieSaphira
How important it is that there is a "." In the names of the entities or a "-"? because these are reserved symbols in xtext and (in the first instance) it does not seem possible to insert them in the regex for checking names.
If you can omit them in the entities names, then the other 3 bullet points will be resolved in the next commit.

[MarieSaphira]

@Bitico
It is not important at all, since the container names (defined in DL) can be different to the database names (defined in ML). So all invalid characters can be replaced when creating the container names. Nothing has to be changed in ML. Sorry if that wasn't clear enough from my previous post.