eons library
Project description
eons python framework
Generalized framework for doing python things.
Design in short: Self-registering functors downloaded just-in-time for use with arbitrary data structures.
Installation
pip install eons
Usage
This library is intended for consumption by other executables.
To create your own executable, override Executor
to add functionality to your program, then create children of Datum
and UserFunctor
for adding your own data structures and operations.
For example implementations, check out:
Design
Configuration File and Fetch()
eons provides a simple means of retrieving variables from a wide array of places. When you Fetch()
a variable, we look through:
- The system environment (e.g.
export some_key="some value"
) - The json configuration file supplied with
--config
(or specified bythis.defualtConfigFile
perConfigure()
) - Arguments supplied at the command line (e.g. specifying
--some-key "some value"
makesFetch(some_key)
return"some value"
) - Member variables of the Executor (e.g.
this.some_key = "some value"
)
The higher the number on the above list, the higher the precedence of the search location. For example, member variables will always be returned before values from the environment.
NOTE: The supplied configuration file must contain only valid json.
GetRegistered()
In addition to dynamically Fetch()ing variables, eons provides a means of dynamically providing instances of classes by name. These classes can be stored on the filesystem or online.
Additionally, when provisioning SelfRegistering classes, both python package and other SelfRegistering class dependencies will be resolved. This means that, in the course of using this library, your system may be changed in order to provide the requested functionality.
Keep reading for more details.
Functors
Functors are classes (objects) that have an invokable ()
operator, which allows you to treat them like functions.
eons uses functors to provide input, analysis, and output functionalities, which are made simple by classical inheritance.
For extensibility, all functors take a **kwargs
argument when called. This allows you to provide arbitrary key word arguments (e.g. key="value") to your objects.
Self Registration
Normally, one has to import
the files they create into their "main" file in order to use them. That does not apply when using eons. Instead, you simply have to derive from an appropriate base class and then call SelfRegistering.RegisterAllClassesInDirectory(...)
(which is usually done for you based on the repo['store']
and defaultRepoDirectory
members), providing the directory of the file as the only argument. This will essentially import
all files in that directory and make them instantiable via SelfRegistering("ClassName")
.
Example
In some MyDatum.py
in a MyData
directory, you might have:
import logging
from eons import Datum
class MyDatum(Datum): #Datum is a useful child of SelfRegistering
def __init__(this, name="only relevant during direct instantiation"):
logging.info(f"init MyDatum")
super().__init__()
From our main.py, we can then call:
import sys, os
from eons import SelfRegistering
SelfRegistering.RegisterAllClassesInDirectory(os.path.join(os.path.dirname(os.path.abspath(__file__)), "MyData"))
Here, we use os.path
to make the file path relevant to the project folder and not the current working directory.
Then, from main, etc. we can call:
myDatum = SelfRegistering("MyDatum")
and we will get a MyDatum
object, fully instantiated.
Online Repository
When using an eons Executor, SelfRegistering classes are retrieved with Executor.GetRegistered(...)
. If the class you are trying to retrieve is not found in the Registered classes, GetRegistered
will try to download a package for the class.
You may add credentials and even provide your own repo url for searching. If credentials are supplied, private packages will be searched before public ones.
Online repository settings can be set through:
--repo-store
--repo-url
--repo-username
--repo-password
You may also publish to the online repository through ebbs
NOTE: per the above section on the Configuration File, you can set repo_username
in the environment to avoid passing credentials on the command line, or worse, you can store them in plain text in the configuration file ;)
Extension
When extending a program that derives from eons, defer to that program's means of extension. However, the following utilities may greatly aid in standardizing downstream code.
User Functor
UserFunctors store all args passed to them in the kgwargs
member. While you can check this member directly for arguments, Fetch(...)
is preferred.
When extending UserFunctor
, please be aware that the following utilities are available to you:
#RETURNS: an opened file object for writing.
#Creates the path if it does not exist.
def CreateFile(this, file, mode="w+"):
...
#Copy a file or folder from source to destination.
#This really shouldn't be so hard...
def Copy(this, source, destination):
...
#Delete a file or folder
def Delete(this, target):
...
#Run whatever.
#DANGEROUS!!!!!
#RETURN: Return value and, optionally, the output as a list of lines.
#per https://stackoverflow.com/questions/803265/getting-realtime-output-using-subprocess
def RunCommand(this, command, saveout=False, raiseExceptions=True):
...
The source for these methods is available in UserFunctor.py.
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