Hiku¶
Hiku is a library to implement Graph APIs. Essential GraphQL support included.
Installation¶
$ pip3 install hiku
Bug fixes and new features are frequently published via release candidates:
$ pip3 install --upgrade --pre hiku
Documentation¶
Read documentation
Optional dependencies¶
graphql-core - for GraphQL support
sqlalchemy - for SQLAlchemy support as a data-source
aiopg - for async PostgreSQL support with aiopg
asyncpg - for async PostgreSQL support with asyncpg
prometheus-client - for Prometheus metrics support
sentry-sdk - for Sentry tracing support
Highlights¶
Not coupled to a single specific query language
Flexibility in result serialization
Natively uses normalized result representation, without data duplication
All concurrency models supported: coroutines, threads
Parallel query execution
No data under-fetching or over-fetching between
client<->server
and betweenserver<->database
No
N+1
problems by designIntroduces a concept of Two-Level Graph in order to decouple data-sources and business-logic
Quick example¶
Graph definition:
from hiku.graph import Graph, Root, Node, Field, Link
from hiku.types import String, Sequence, TypeRef
def characters_data(fields, ids):
data = {
1: {'name': 'James T. Kirk', 'species': 'Human'},
2: {'name': 'Spock', 'species': 'Vulcan/Human'},
3: {'name': 'Leonard McCoy', 'species': 'Human'},
}
return [[data[i][f.name] for f in fields] for i in ids]
def characters_link():
return [1, 2, 3]
GRAPH = Graph([
Node('Character', [
Field('name', String, characters_data),
Field('species', String, characters_data),
]),
Root([
Link('characters', Sequence[TypeRef['Character']],
characters_link, requires=None),
]),
])
Query:
from hiku.schema import Schema
from hiku.builder import Q, build
from hiku.executors.sync import SyncExecutor
schema = Schema(SyncExecutor(), GRAPH)
result = schema.execute_sync(build([
Q.characters[
Q.name,
Q.species,
],
]))
# use result in your code
for character in result.data["characters"]:
print(character["name"], '-', character["species"])
Output:
James T. Kirk - Human
Spock - Vulcan/Human
Leonard McCoy - Human
Contributing¶
Use Tox in order to test and lint your changes.