sqlalchemy_to_json_schema is the library for converting sqlalchemys's model to jsonschema.
- using sqlalchemy_to_json_schema as command
- using sqlalchemy_to_json_schema as library
having three output styles.
- NoForeignKeyWalker -- ignore relationships
- ForeignKeyWalker -- expecting the information about relationship is foreign key
- StructuralWalker -- fullset output(expecting the information about relationship is full JSON data)
dumping json with above three output styles.
target models are here. Group and User.
# -*- coding:utf-8 -*-
import sqlalchemy as sa
import sqlalchemy.orm as orm
from sqlalchemy.orm import declarative_base
Base = declarative_base()
class Group(Base):
"""model for test"""
__tablename__ = "Group"
pk = sa.Column(sa.Integer, primary_key=True, doc="primary key")
name = sa.Column(sa.String(255), default="", nullable=False)
class User(Base):
__tablename__ = "User"
pk = sa.Column(sa.Integer, primary_key=True, doc="primary key")
name = sa.Column(sa.String(255), default="", nullable=True)
group_id = sa.Column(sa.Integer, sa.ForeignKey(Group.pk), nullable=False)
group = orm.relationship(Group, uselist=False, backref="users")import pprint as pp
from sqlalchemy_to_json_schema.schema_factory import SchemaFactory
from sqlalchemy_to_json_schema.schema_factory import NoForeignKeyWalker
factory = SchemaFactory(NoForeignKeyWalker)
pp.pprint(factory(User))
"""
{'properties': {'name': {'maxLength': 255, 'type': 'string'},
'pk': {'description': 'primary key', 'type': 'integer'}},
'required': ['pk'],
'title': 'User',
'type': 'object'}
"""import pprint as pp
from sqlalchemy_to_json_schema.schema_factory import SchemaFactory
from sqlalchemy_to_json_schema.schema_factory import ForeignKeyWalker
factory = SchemaFactory(ForeignKeyWalker)
pp.pprint(factory(User))
"""
{'properties': {'group_id': {'type': 'integer'},
'name': {'maxLength': 255, 'type': 'string'},
'pk': {'description': 'primary key', 'type': 'integer'}},
'required': ['pk', 'group_id'],
'title': 'User',
'type': 'object'}
"""import pprint as pp
from sqlalchemy_to_json_schema.schema_factory import SchemaFactory
from sqlalchemy_to_json_schema.schema_factory import StructuralWalker
factory = SchemaFactory(StructuralWalker)
pp.pprint(factory(User))
"""
{'definitions': {'Group': {'properties': {'pk': {'description': 'primary key',
'type': 'integer'},
'name': {'maxLength': 255,
'type': 'string'}},
'type': 'object'}},
'properties': {'pk': {'description': 'primary key', 'type': 'integer'},
'name': {'maxLength': 255, 'type': 'string'},
'group': {'$ref': '#/definitions/Group'}},
'required': ['pk'],
'title': 'User',
'type': 'object'}
"""
pp.pprint(factory(Group))
"""
{'definitions': {'User': {'properties': {'pk': {'description': 'primary key',
'type': 'integer'},
'name': {'maxLength': 255,
'type': 'string
'}},
'type': 'object'}},
'description': 'model for test',
'properties': {'pk': {'description': 'primary key', 'type': 'integer'},
'name': {'maxLength': 255, 'type': 'string'},
'users': {'items': {'$ref': '#/definitions/User'},
'type': 'array'}},
'required': ['pk', 'name'],
'title': 'Group',
'type': 'object'}using sqlalchemy_to_json_schema as command (the command name is also sqlalchemy_to_json_schema).
$ sqlalchemy_to_json_schema --help
usage: sqlalchemy_to_json_schema [-h] [--walker {noforeignkey,foreignkey,structural}]
[--decision {default,fullset}] [--depth DEPTH]
[--out OUT]
target
positional arguments:
target the module or class to extract schemas from
optional arguments:
-h, --help show this help message and exit
--walker {noforeignkey,foreignkey,structural}
--decision {default,fullset}
--depth DEPTH
--out OUT output to fileIf above two model definitions (User,Group) are existed in tests.models.
Target is the class position or module position. for example,
- class position --
tests.models:User - module position --
tests.models
Using StructuralWalker via command line (--walker structural).
Of course, NoForeignKeyWalker is noforeignkey, and ForeignKeyWalker is foreignkey.
$ sqlalchemy_to_json_schema --walker structural tests.models:Group
{
"definitions": {
"Group": {
"properties": {
"color": {
"enum": [
"red",
"green",
"yellow",
"blue"
],
"maxLength": 6,
"type": "string"
},
"created_at": {
"format": "date-time",
"type": "string"
},
"name": {
"maxLength": 255,
"type": "string"
},
"pk": {
"description": "primary key",
"type": "integer"
},
"users": {
"items": {
"$ref": "#/definitions/User"
},
"type": "array"
}
},
"required": [
"pk"
],
"title": "Group",
"type": "object"
},
"User": {
"properties": {
"created_at": {
"format": "date-time",
"type": "string"
},
"name": {
"maxLength": 255,
"type": "string"
},
"pk": {
"description": "primary key",
"type": "integer"
}
},
"required": [
"pk"
],
"type": "object"
}
}
}Output is not same when using Walker-class, directly. This is handy output for something like a swagger(OpenAPI 2.0)'s tool.
what is --decision? (TODO: gentle description)
$ sqlalchemy_to_json_schema --walker structural tests.models:User | jq . -S > /tmp/default.json
$ sqlalchemy_to_json_schema --decision useforeignkey --walker structural tests.models:User | jq . -S > /tmp/useforeignkey.json
$ diff -u /tmp/default.json /tmp/useforeignkey.json--- /tmp/default.json 2017-01-02 22:49:44.000000000 +0900
+++ /tmp/useforeignkey.json 2017-01-02 22:53:13.000000000 +0900
@@ -1,43 +1,14 @@
{
"definitions": {
- "Group": {
- "properties": {
- "color": {
- "enum": [
- "red",
- "green",
- "yellow",
- "blue"
- ],
- "maxLength": 6,
- "type": "string"
- },
- "created_at": {
- "format": "date-time",
- "type": "string"
- },
- "name": {
- "maxLength": 255,
- "type": "string"
- },
- "pk": {
- "description": "primary key",
- "type": "integer"
- }
- },
- "required": [
- "pk"
- ],
- "type": "object"
- },
"User": {
"properties": {
"created_at": {
"format": "date-time",
"type": "string"
},
- "group": {
- "$ref": "#/definitions/Group"
+ "group_id": {
+ "relation": "group",
+ "type": "integer"
},
"name": {
"maxLength": 255,