varco-core 0.0.3

Backend-agnostic domain model, service layer, authorization, query AST and DTOs for varco

varco-core

Backend-agnostic domain model and service layer for varco.

Provides the pure-Python building blocks that all backend packages depend on — no ORM imports at the core layer. Pair it with varco-sa (SQLAlchemy) or varco-beanie (MongoDB) for a concrete backend.

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Install

pip install varco-core

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Features

• Domain model — DomainModel, AuditedDomainModel, VersionedDomainModel, soft-delete and multi-tenant variants
• Generic async service — AsyncService with built-in create / read / update / delete / list, pagination, soft-delete, and multi-tenancy mixins
• Authorization — AbstractAuthorizer, GrantBasedAuthorizer, RoleBasedAuthorizer, OwnershipAuthorizer
• DTO layer — CreateDTO, ReadDTO, UpdateDTO, generate_dtos() factory, cursor-based pagination
• Fluent query builder — QueryBuilder → AST → QueryParser (string → AST via Lark grammar); backend-independent
• JWT / JWK — JwtBuilder, JwtParser, JwkBuilder, MultiKeyAuthority, OIDC + PEM sources
• Tracing — correlation_context, current_correlation_id, CorrelationIdFilter
• DI-ready — all service classes are designed for constructor injection via providify

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What's in the package

Module	Purpose
model.py	DomainModel, AuditedDomainModel, VersionedDomainModel, SoftDeleteMixin, TenantMixin and derived classes
meta.py	FieldHint, ForeignKey, PrimaryKey, PKStrategy, constraints, pk_field()
mapper.py	AbstractMapper — bidirectional ORM ↔ domain translation
repository.py	AsyncRepository ABC — CRUD + exists() + stream_by_query()
uow.py	AsyncUnitOfWork ABC
registry.py	DomainModelRegistry + @register decorator
providers.py	RepositoryProvider ABC
assembler.py	AbstractDTOAssembler[D, C, R, U]
service/base.py	AsyncService, IUoWProvider
service/tenant.py	TenantAwareService, TenantUoWProvider, tenant_context
service/soft_delete.py	SoftDeleteService
service/types.py	Assembler alias, ServiceProtocol
auth/	AbstractAuthorizer, Action, AuthContext, ResourceGrant
auth/helpers.py	GrantBasedAuthorizer, OwnershipAuthorizer, RoleBasedAuthorizer
exception/	FastrestErrorCodes, ErrorCode, ErrorMessage, HTTP error mapping
tracing.py	correlation_context, current_correlation_id, CorrelationIdFilter
query/	QueryBuilder, QueryParams, QueryParser, AST visitors
jwt/	JwtBuilder, JwtParser, JwtUtil, JsonWebToken
jwk/	JwkBuilder, JsonWebKey, JsonWebKeySet
authority/	JwtAuthority, MultiKeyAuthority, TrustedIssuerRegistry, OIDC/PEM sources

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Quick start

Define a domain model

from __future__ import annotations
from typing import Annotated
from varco_core import AuditedDomainModel
from varco_core.meta import FieldHint, PrimaryKey, PKStrategy, pk_field

class Post(AuditedDomainModel):
    pk: Annotated[int, PrimaryKey(PKStrategy.INT_AUTO)] = pk_field()
    title: Annotated[str, FieldHint(max_length=200)]
    body: str
    published: bool = False

Wire a service with DI

from varco_core import AsyncService, IUoWProvider
from varco_core.assembler import AbstractDTOAssembler
from varco_core.auth import AbstractAuthorizer
from providify import Inject, Singleton

@Singleton
class PostService(AsyncService[Post, int, CreatePostDTO, PostReadDTO, UpdatePostDTO]):
    def __init__(
        self,
        uow_provider: Inject[IUoWProvider],
        authorizer:   Inject[AbstractAuthorizer],
        assembler:    Inject[AbstractDTOAssembler[Post, CreatePostDTO, PostReadDTO, UpdatePostDTO]],
    ) -> None:
        super().__init__(uow_provider=uow_provider, authorizer=authorizer, assembler=assembler)

    def _get_repo(self, uow): return uow.posts

Build and run a query

from varco_core import QueryBuilder, QueryParams

params = QueryParams(
    node=QueryBuilder().eq("published", True).and_().gt("pk", 10).build(),
    limit=20,
    offset=0,
)

# Parse from a query string (e.g. from a URL parameter)
from varco_core import QueryParser
params = QueryParser().parse('published == true AND pk > 10', limit=20)

JWT — build and verify tokens

from varco_core import JwtBuilder, JwtParser

token = JwtBuilder(secret="s3cr3t").subject("user-42").expires_in(3600).build()
payload = JwtParser(secret="s3cr3t").parse(token)

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Related packages

Package	Description
varco-sa	SQLAlchemy async backend
varco-beanie	Beanie / Motor MongoDB backend

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Links

• Repository: https://github.com/edoardoscarpaci/varco
• Full docs: https://github.com/edoardoscarpaci/varco#readme
• Issue tracker: https://github.com/edoardoscarpaci/varco/issues