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https://github.com/hazarddede/argresolver
Resolves missing function arguments at runtime
https://github.com/hazarddede/argresolver
arguments framework python3 utility
Last synced: about 7 hours ago
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Resolves missing function arguments at runtime
- Host: GitHub
- URL: https://github.com/hazarddede/argresolver
- Owner: HazardDede
- License: mit
- Created: 2018-05-14T21:54:03.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2019-03-30T10:58:25.000Z (over 5 years ago)
- Last Synced: 2024-10-28T16:18:11.159Z (19 days ago)
- Topics: arguments, framework, python3, utility
- Language: Python
- Size: 36.1 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ArgResolver v0.3.3
[](https://badge.fury.io/py/argresolver)
[](https://travis-ci.org/HazardDede/argresolver)
[](https://coveralls.io/github/HazardDede/argresolver?branch=master)
[](https://opensource.org/licenses/MIT)
Resolver is a simple decorator for resolving (missing) arguments at runtime.
It performs various tasks from looking up arguments from the environment variable scope to simple service dependency injection.
1\. [Resolver](#resolver)
1.1\. [Environment](#environment)
1.2\. [Map](#map)
1.3\. [Chain](#chain)
## 1\. Resolver
### 1.1\. Environment
```python
# We inject arguments from the environment variables scope to a simple function
# We use a `prefix` to minimize clashes with other components
# username will have a correponding DB_USERNAME, same for password and database
from argresolver import Environment
from argresolver.utils import modified_environ # We use it to alter the environment variables
@Environment()
def connect(host, user, password):
print("Connecting: {user}:{password}@{host}".format(**locals()))
with modified_environ(PASSWORD='my_pass'):
connect('localhost', 'admin')
# Prints: Connecting: admin:my_pass@localhost
```
```python
# We inject arguments from the environment variables scope
# to an instance __init__.
# We use a `prefix` to minimize clashes with other components that have a username / password.
# Argument username will have a correponding DB_USERNAME, same for password and database
from argresolver import Environment
from argresolver.utils import modified_environ # We use it to alter the environment variables
class Connection:
@Environment(prefix='DB')
def __init__(self, username, password, database='default'):
self.username = username
self.password = password
self.database = database
def __str__(self):
# Hint: In a real world example you won't put your password in here ;-)
return "Connection(username='{self.username}', password='{self.password}'"\
", database='{self.database}')".format(self=self)
with modified_environ(DB_USERNAME='admin', DB_PASSWORD='secret'):
conn = Connection()
print(str(conn)) # Connection(username='admin', password='secret', database='default')
```
### 1.2\. Map
```python
# We use the Map resolver to override an argument's default value
# that is better suited for our needs.
from argresolver import Map
# Let's assume we cannot touch this code...
class Foo:
def __init__(self, arg1, arg2='I_dont_like_this_default'):
self.arg1 = arg1
self.arg2 = arg2
def __str__(self):
return "Foo(arg1='{self.arg1}', arg2='{self.arg2}')".format(self=self)
# But we can alter the class and wrap a resolver around the class __init__
Foo.__init__ = Map(dict(arg2="better_default"), default_override=True)(Foo.__init__)
foo = Foo("this is arg1")
print(str(foo)) # Foo(arg1='this is arg1', arg2='better_default')
```
### 1.3\. Chain
```python
# We do some automatic dependency injection with fallback
from argresolver import Chain, Const, Map
inject = Chain(
Map(dict(service1="Service1", service2="Service2")),
Const("Fallback Service")
)
class Orchestration:
@inject
def business_process1(self, service1, service2):
print("Calling service:", service1)
print("Calling service:", service2)
@inject
def business_process2(self, service1, service3):
print("Calling service:", service1)
print("Calling service:", service3)
orchester = Orchestration()
orchester.business_process1()
# Prints:
# Calling service: Service1
# Calling service: Service2
orchester.business_process2()
# Prints:
# Calling service: Service1
# Calling service: Fallback Service
```