feat(appsync): add Router to allow large resolver composition

[michaelbrewer]

Add support for splitting resolvers into multiple files

Issue #, if available:

• #652

Description of changes:

Add support for splitting an AppSyncResolver into multiple files (very similar to #645).

Example main.py:

from typing import Dict

from aws_lambda_powertools import Tracer, Logger
from aws_lambda_powertools.event_handler import AppSyncResolver
from aws_lambda_powertools.logging.correlation_paths import APPSYNC_RESOLVER
from aws_lambda_powertools.utilities.typing import LambdaContext

from .resolvers import location, merchant

tracer = Tracer()
logger = Logger()
app = AppSyncResolver()
app.include_router(location.router)
app.include_router(merchant.router)


@tracer.capture_lambda_handler
@logger.inject_lambda_context(correlation_id_path=APPSYNC_RESOLVER)
def lambda_handler(event: Dict, context: LambdaContext):
    app.resolve(event, context)

Example resolvers/location.py:

from typing import List, Dict, Any

from aws_lambda_powertools import Logger
from aws_lambda_powertools.event_handler.appsync import Router

logger = Logger(child=True)
router = Router()


@router.resolver(type_name="Query", field_name="listLocations")
def list_locations(merchant_id: str) -> List[Dict[str, Any]]:
    return [{"name": "Location name", "merchant_id": merchant_id}]


@router.resolver(type_name="Location", field_name="status")
def resolve_status(merchant_id: str) -> str:
    logger.debug(f"Resolve status for merchant_id: {merchant_id}")
    return "FOO"

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

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[codecov-commenter]

Codecov Report

Merging #776 (3a2c2e8) into develop (c3769f3) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #776   +/-   ##
========================================
  Coverage    99.97%   99.97%           
========================================
  Files          116      116           
  Lines         4939     4948    +9     
  Branches       275      275           
========================================
+ Hits          4938     4947    +9     
  Partials         1        1           

Impacted Files	Coverage Δ
aws_lambda_powertools/event_handler/appsync.py	100.00% <100.00%> (ø)

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[heitorlessa]

Question on whether Router is a better name than Resolver since we already have AppSyncResolver