Json schema validator, how to validate if key is not static - json

Question

I am trying to validate this specific schema:
{
"messages": [
{
"name": "test msg",
"id": "0x100",
"signals": {
"0": {"name": "Engine RPM", "bit_length": 16},
"16": {"name": "Gear", "bit_length": 3},
"19": {"name": "Battery Voltage", "bit_length": 5}
}
}
]
}
I am using the python from jsonschema import Draft4Validator to validate this schema... however I am not sure how to continue.
This is my current schema validation so far:
{
"$schema" : "https://json-schema.org/schema#",
"type" : "object",
"properties" :
{
"messages" :
{
"type" : "array",
"items" :
{
"properties" :
{
"name" :
{
"type" : "string"
},
"id" :
{
"type" : "string"
},
"signals" :
{
"type" : "object"
},
"properties" :
{
}
},
"required": ["name", "id", "signals"]
}
}
}
}
The problem I am facing is I am not sure how to deal with the objects that are in the "signals" key as they start with a string and are NOT consistent ("0", "16", "19")... How could I go about validating this by ensuring the type is always a string, disregarding whether or not the string is consistent.
Thanks to all of those who reply in advance.

Answer 1

I was able to accomplish this by doing the following:
{
"$schema" : "https://json-schema.org/schema#",
"type" : "object",
"properties" :
{
"messages" :
{
"type" : "array",
"items" :
{
"properties" :
{
"name" :
{
"type" : "string"
},
"id" :
{
"type" : "string"
},
"signals" :
{
"type" : "object"
},
"properties" :
{
"start_bit" :
{
"type" : "object",
"properties" :
{
"name" :
{
"type" : "string"
},
"bit_length" :
{
"type" : "string"
},
"factor" :
{
"type" : "string"
},
"offset" :
{
"type" : "string"
}
},
"required" : ["name", "bit_length", "factor", "offset"]
}
}
},
"required": ["name", "id", "signals"]
}
}
}
}
To "avoid" having to keep the string consistent, in the validator file, I can put any string (obviously it makes more sense to name the string what is represents, in my case "start_bit") and then by NOT having it be required.