graphql-python/graphene-django
1
1
Fork 0
mirror of https://github.com/graphql-python/graphene-django.git synced 2025-04-15 14:42:06 +03:00
Code Issues Packages Projects Releases Wiki Activity

Create and handle database atomic mutations

Browse Source
This commit is contained in:
Ignacio Orlandini 2020-09-21 22:51:25 -03:00
parent 09c5215abe
commit 7bd29acde6
4 changed files with 246 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
docs/mutations.rst
View File

@ -255,3 +255,95 @@ rolls back the transaction.
inefficient when traffic increases. Opening a transaction for every request has some
overhead. The impact on performance depends on the query patterns of your application
and on how well your database handles locking.
Check the next section for a better solution.
Tying transactions to mutations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A mutation can contain multiple fields, just like a query. There's one important
distinction between queries and mutations, other than the name:
..
`While query fields are executed in parallel, mutation fields run in series, one
after the other.`
This means that if we send two ``incrementCredits`` mutations in one request, the first
is guaranteed to finish before the second begins, ensuring that we don't end up with a
race condition with ourselves.
On the other hand, if the first ``incrementCredits`` runs successfully but the second
one does not, the operation cannot be retried as it is. That's why is a good idea to
run all mutation fields in a transaction, to guarantee all occur or nothing occurs.
To enable this behavior for all databases set the graphene ``ATOMIC_MUTATIONS`` settings
to ``True`` in your settings file:
.. code:: python
GRAPHENE = {
# ...
"ATOMIC_MUTATIONS": True,
}
On the contrary, if you want to enable this behavior for a specific database, set
``ATOMIC_MUTATIONS`` to ``True`` in your database settings:
.. code:: python
DATABASES = {
"default": {
# ...
"ATOMIC_MUTATIONS": True,
},
# ...
}
Now, given the following example mutation:
.. code::
mutation IncreaseCreditsTwice {
increaseCredits1: increaseCredits(input: { amount: 10 }) {
balance
errors {
field
messages
}
}
increaseCredits2: increaseCredits(input: { amount: -1 }) {
balance
errors {
field
messages
}
}
}
The server is going to return something like:
.. code:: json
{
"data": {
"increaseCredits1": {
"balance": 10.0,
"errors": []
},
"increaseCredits2": {
"balance": null,
"errors": [
{
"field": "amount",
"message": "Amount should be a positive number"
}
]
},
}
}
But the balance will remain the same.

1
graphene_django/settings.py
View File

@ -45,6 +45,7 @@ DEFAULTS = {
# This sets headerEditorEnabled GraphiQL option, for details go to
# https://github.com/graphql/graphiql/tree/main/packages/graphiql#options
"GRAPHIQL_HEADER_EDITOR_ENABLED": True,
"ATOMIC_MUTATIONS": False,
}
if settings.DEBUG:

134
graphene_django/tests/test_views.py
View File

@ -6,6 +6,8 @@ from mock import patch
from django.db import connection
from graphene_django.settings import graphene_settings
from .models import Pet
try:
@ -567,9 +569,13 @@ def test_passes_request_into_context_request(client):
def test_form_mutation_multiple_creation_invalid_atomic_request(client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = False
connection.settings_dict["ATOMIC_REQUESTS"] = True
graphene_settings.ATOMIC_MUTATIONS = False
query = """
mutation PetMutations {
@ -602,13 +608,109 @@ def test_form_mutation_multiple_creation_invalid_atomic_request(client):
assert Pet.objects.count() == 0
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations
def test_form_mutation_multiple_creation_invalid_non_atomic_request(client):
def test_form_mutation_multiple_creation_invalid_atomic_mutation_1(client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = True
connection.settings_dict["ATOMIC_REQUESTS"] = False
graphene_settings.ATOMIC_MUTATIONS = False
query = """
mutation PetMutations {
petFormMutation1: petFormMutation(input: { name: "Mia", age: 99 }) {
errors {
field
messages
}
}
petFormMutation2: petFormMutation(input: { name: "Enzo", age: 0 }) {
errors {
field
messages
}
}
}
"""
response = client.post(url_string(query=query))
content = response_json(response)
assert "errors" not in content
assert content["data"]["petFormMutation1"]["errors"] == [
{"field": "age", "messages": ["Too old"]}
]
assert content["data"]["petFormMutation2"]["errors"] == []
assert Pet.objects.count() == 0
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations
def test_form_mutation_multiple_creation_invalid_atomic_mutation_2(client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = False
connection.settings_dict["ATOMIC_REQUESTS"] = False
graphene_settings.ATOMIC_MUTATIONS = True
query = """
mutation PetMutations {
petFormMutation1: petFormMutation(input: { name: "Mia", age: 99 }) {
errors {
field
messages
}
}
petFormMutation2: petFormMutation(input: { name: "Enzo", age: 0 }) {
errors {
field
messages
}
}
}
"""
response = client.post(url_string(query=query))
content = response_json(response)
assert "errors" not in content
assert content["data"]["petFormMutation1"]["errors"] == [
{"field": "age", "messages": ["Too old"]}
]
assert content["data"]["petFormMutation2"]["errors"] == []
assert Pet.objects.count() == 0
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations
def test_form_mutation_multiple_creation_invalid_non_atomic(client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = False
connection.settings_dict["ATOMIC_REQUESTS"] = False
graphene_settings.ATOMIC_MUTATIONS = False
query = """
mutation PetMutations {
@ -645,13 +747,19 @@ def test_form_mutation_multiple_creation_invalid_non_atomic_request(client):
assert pet.age == 0
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations
def test_model_form_mutation_multiple_creation_invalid_atomic_request(client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = False
connection.settings_dict["ATOMIC_REQUESTS"] = True
graphene_settings.ATOMIC_MUTATIONS = False
query = """
mutation PetMutations {
@ -693,13 +801,19 @@ def test_model_form_mutation_multiple_creation_invalid_atomic_request(client):
assert Pet.objects.count() == 0
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations
def test_model_form_mutation_multiple_creation_invalid_non_atomic_request(client):
def test_model_form_mutation_multiple_creation_invalid_non_atomic(client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = False
connection.settings_dict["ATOMIC_REQUESTS"] = False
graphene_settings.ATOMIC_MUTATIONS = False
query = """
mutation PetMutations {
@ -745,30 +859,44 @@ def test_model_form_mutation_multiple_creation_invalid_non_atomic_request(client
assert pet.age == 0
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations
@patch("rest_framework.views.transaction.set_rollback")
def test_query_errors_atomic_request(set_rollback_mock, client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = False
connection.settings_dict["ATOMIC_REQUESTS"] = True
graphene_settings.ATOMIC_MUTATIONS = False
client.get(url_string(query="force error"))
set_rollback_mock.assert_called_once_with(True)
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations
@patch("rest_framework.views.transaction.set_rollback")
def test_query_errors_non_atomic_request(set_rollback_mock, client):
def test_query_errors_non_atomic(set_rollback_mock, client):
old_atomic_mutations = connection.settings_dict.get("ATOMIC_MUTATIONS", False)
old_atomic_requests = connection.settings_dict["ATOMIC_REQUESTS"]
old_graphene_atomic_mutations = graphene_settings.ATOMIC_MUTATIONS
try:
connection.settings_dict["ATOMIC_MUTATIONS"] = False
connection.settings_dict["ATOMIC_REQUESTS"] = False
graphene_settings.ATOMIC_MUTATIONS = False
client.get(url_string(query="force error"))
set_rollback_mock.assert_not_called()
finally:
connection.settings_dict["ATOMIC_MUTATIONS"] = old_atomic_mutations
connection.settings_dict["ATOMIC_REQUESTS"] = old_atomic_requests
graphene_settings.ATOMIC_MUTATIONS = old_graphene_atomic_mutations

30
graphene_django/views.py
View File

@ -3,6 +3,7 @@ import json
import re
import six
from django.db import connection, transaction
from django.http import HttpResponse, HttpResponseNotAllowed
from django.http.response import HttpResponseBadRequest
from django.shortcuts import render
@ -320,14 +321,27 @@ class GraphQLView(View):
# executor is not a valid argument in all backends
extra_options["executor"] = self.executor
return document.execute(
root_value=self.get_root_value(request),
variable_values=variables,
operation_name=operation_name,
context_value=self.get_context(request),
middleware=self.get_middleware(request),
**extra_options
)
operation_type = document.get_operation_type(operation_name)
options = {
"root_value": self.get_root_value(request),
"variable_values": variables,
"operation_name": operation_name,
"context_value": self.get_context(request),
"middleware": self.get_middleware(request),
**extra_options,
}
if operation_type == "mutation" and (
graphene_settings.ATOMIC_MUTATIONS is True
or connection.settings_dict.get("ATOMIC_MUTATIONS", False) is True
):
with transaction.atomic():
result = document.execute(**options)
if getattr(request, MUTATION_ERRORS_FLAG, False) is True:
transaction.set_rollback(True)
return result
return document.execute(**options)
except Exception as e:
return ExecutionResult(errors=[e], invalid=True)