eons 3.1.6

Eons Python Framework

Eons Python Framework

The Eons Python Framework provides a user-friendly Python extension to the Develop Biology project. This means eons helps you blur the lines between what it means to be, have, and do. Gone are the days of classes meaning "to be", members meaning "to have", and functions meaning "to do". With Eons and Biology, they are all one and the same.

Design in short: Self-registering, sequential functors with implicit and automatic inheritance, downloaded just-in-time for use with arbitrary data structures.

Kind

(totally unrelated to the Kind Proof Language; we just wanted a short synonym to "type" that didn't collide with Python's reserved keywords)

Eons provides an easy plug-and-play style of development by mElderlanging the myriad Python packages we all love with our own custom syntax. We aim to provide you with something that is familiar when you want it to be, and powerful when you need it to be.

The most condensed form of our syntax is as follows:

@eons.kind(parent/base, classes)
def ClassName(
    member,
    variables,
    which = "are injected via Fetch"
):
    # Your code goes here.
    this.isHow = "you reference the object / instance"

Here's a more complete example:

import eons

@eons.kind(eons.StandardFunctor)
def MyFunctor(
	external_method = eons.inject('SomeFarAwayFunctor'),
	constructor = f"""
# Until Execution Blocks can be created in Parameter Blocks, formatted, multiline strings are the only way to handle arbitrary logic.

this.classVariable = "Whatever you want!"
""",
):
	this.result.data.myResult = external_method(this.classVariable)

This language style derives from the Eons Language of Development for Entropic Reduction (Elderlang). The only real features missing, besides some nicer character choices (e.g. use of {} for Execution Blocks) are Space Autofill, and the ability to define functions, classes, and Functors in Parameter Blocks (i.e. ()). So, for now, you're restricted to just lambdas or breaking your larger logic out into a separate Functor.

The main differences between the Kind syntax and the Eons Language of Development are:

• The @eons.kind decorator is used to declare a Type Block.
• this is used instead of ./ (or self in Python).
• epidef is used instead of ../.
• Spatial Separation is big endian, rather than how domains are named (i.e. LSB..TLD).
• Sequences are built by eons.Flow()s (still under development).
• Python STILL does not have multiline comments >:(
• Python has both dictionaries and lists, vs just Containers in Elderlang
• def is required to start a Parameter Block & : is required to start an Execution Block, both of which must always happen in that order (and be preceded by a Type Block).
• Convenient type casting is not fully implemented in Kind.
• Access control is not yet implemented in Kind.

Parent

You can access the parent class (not a cast of the current object to a parent object) via the parent member. For example, you can call return this.parent.Function(this) to call the parent's Function() method. Note that you must still pass the instance (this) explicitly, since this.parent returns a class, not an instance.

Caller

When composing Functors, the this keyword is often ambiguous. Between functions of a class, this always refers to the class itself. However, when each function is also a class, does this mean the Functor or the class to which it belongs?

To answer this question, Elderlang introduces the keyword ./. In Kind, we simply call this epidef.

So, you can use epidef.someMember to share access across Functors composed by the same class, and this.someMember to access the Functor's own members.

Access Control

There is no true access control in Python. So, implementing it via Biology has been slow going. However, for now, you can use something akin to Elderlang's public(...) Functor to make defining method injection easier.

Instead of saying:

@eons.kind(eons.StandardFunctor)
def MyFunctor(
    Method1 = eons.inject('Method1'),
    method2 = eons.inject('SomeOtherFunctor'),
    MeThOd3 = eons.inject('METHOD3'),
): 
    pass

you can say:

@eons.kind(eons.StandardFunctor)
def MyFunctor(
    doesNotMatter = eons.public_methods(
        'Method1',
        method3 = 'SomeOtherFunctor',
        MeThOd3 = 'METHOD3',
    ),
): 
    pass

Unfortunately, you have to assign the result of eons.public_methods to a key word arg. However, the arg name is never used. We recommend using public or something trivial.

Eventually, a generic eons.public(...) method should exist such that you can specify variable in addition to methods, but that is not yet implemented.

Installation

pip install eons

Usage

This library is intended for consumption by other libraries and executables. To create your own executable, override Executor to add functionality to your program then create children of Datum and Functor for adding your own data structures and operations.

For example implementations, check out:

• apie
• ebbs
• emi

Arguments available to all Eons Executors:

• -v or --verbose (count, i.e -vv = 2) or --verbosity #, where # is some number, or the verbosity environment or config value: will show more information and increase the logging level, e.g. print debug messages; see log-levels, below for more info.
• --config or -c (string): the path to a json config file from which other values may be retrieved.
• --no-repo or the no_repo environment or config value (bool, i.e. 'True', 'true', etc.): whether or not to enable reaching out to online servers for code (see Dynamic Functionality, below).
• --log-file or the log_file environment or config value (string; supports formatting, e.g. '/var/log/eons/{this.name}.log'): optional value for logging to a file in addition to stderr.
• --log-time-stardate or the log_time_stardate environment or config value (bool): whether or not to use Eons Official Time stardate time in logs (default is true).
• --log-indentation (bool): whether or not tab out logs; see indentation, below.
• --log-tab-width (int): how many spaces to use for indentation; see indentation, below.
• --log-aggregate (bool): whether or not to send logs to a remote aggregation service; see aggregation, below.
• --log-aggregate-url (string): the url of the remote aggregation service; see aggregation, below.

Features

Eons supports 5 major features:

• Get inputs to functors by drilling down through multiple layers.
• Allow functors to change behavior with their order of execution.
• Provide functionality by downloading functors on the fly.
• Managed composition through External Methods.
• Resolve errors through dynamic resolution by functors.

Inputs Through 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:

1. The system environment (e.g. export some_key="some value")
2. The json configuration file supplied with --config (or specified by this.default.config.files per Configure())
3. Arguments supplied at the command line (e.g. specifying --some-key "some value" makes Fetch(some_key) return "some value")
4. 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.

Downstream implementors of the Eons library may optionally extend the Fetch() method to look through whatever layers are appropriate for their inputs.

You are also allowed to customize the order of each layer by reordering the fetchFrom member (list).

NOTE: The supplied configuration file must contain only valid json.

Global Fetch

Eons provides an easy way to query the configuration values provided to it: a global Fetch() function.

Calling eons.Fetch('desired_config_value') will return the result of invoking the Executor's Fetch method. This means any cli args, config values, environment variables, and anything else your Executor is configured to fetchFrom will be searched for your desired_config_value. This does not allow you to search a particular Functor's member variables (besides the Executor's). So, you can't execute a chain of Functors and then check the result using the global Fetch().

To make this even easier, we aliased the global Fetch as f(). You can just type eons.f('whatever') and get the value of whatever!

And, if that's too hard for you, you can use a @recoverable method (see Error Resolution, below) and just type whatever. Eons will do the hard work of catching the NameError and looking up the value. For an example, check out the ResolvableByFetchFunctor, under test.

Implicit Inheritance

The purpose of Implicit Inheritance is to provide developers with a tool for separating implementation and usage, thus allowing development to occur in smaller, logical pieces instead of monoliths (even modular ones). Using the Implicit Inheritance system, you can build libraries piece by piece and assemble them in different orders to achieve different results. For example, a DoStuff Functor might call Do(whatever_was_requested) but might rely on a preceding Functor to implement the Do() Method. If both DoStuffLocally and DoStuffRemotely both define Do(), we can choose how we want to do stuff entirely by the order of execution (i.e. locally vs remotely, in this case). In other words, by choosing which Functor comes before DoStuff, you can effectively choose which members and methods you want to include in your "implicit library" or "implied base class".

Functors contain a next member which enables not just single-function execution but sequences of multiple functions. To maximize the potential these sequences offer, the Eons library allows turning member functions into Methods via the @eons.method() decorator. Methods are, themselves, Functors and can be transferred to other Functors to dynamically populate member functions. We have made it so that if you run some sequence like [FirstFunctor, SecondFunctor], the SecondFunctor automatically inherits the methods of FirstFunctor in addition to being able to access member variables from the FirstFunctor. We call this "Implicit Inheritance". Implicit Inheritance is not true inheritance. In the example above SecondFunctor does not (have to) share a type with FirstFunctor (besides eons.Functor). Implicit Inheritance is also determined dynamically at runtime and cannot be (easily) programmed.

NOTE: to make a Method available to following Functors, you must set propagate=True (e.g. @eons.method(propagate=True))

Methods do not participate in the main, user-requested sequence; instead, Methods create their own sequence. When a preceding Functor defines the same Method as the Functor currently executing, the current Functor can add the preceding Methods to its own either before or after, as controlled by the configuration of each of the current Functor's Methods. This makes it possible to simply setup or tweak functionality within each Method. Thus, a single function may be assembled from the partial implementations of many different definitions.

If that alone wasn't enough, eons.Method() also endows you with the ability to change the code that's written before Python interprets it. You can specify eons.Method(impl='InterpretMyCustomSyntax') or whatever you would like. Ideally, this will allow us to write Functors using any language. At the very least, we can tweak Python to add things like ++, etc.

Dynamic Functionality via GetRegistered()

In addition to dynamically Fetching variables, Eons provides a means of dynamically providing instances of classes by name. These classes can be stored on the filesystem or online through Eons Infrastructure Technologies.

When provisioning SelfRegistering classes (below), 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.

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, the ErrorResolution, install_from_repo 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 ;)

Managed Composition via @eons.method(impl="External")

Composition is a means of building complexity through encapsulation and typically answers the question of "has a ____", where classic inheritance answers "is a ____". Eons provides a means of making composition easy through the External Method implementation.

For example, consider:

class MyClass(eons.Functor):
    @method(impl="External")
    def MyExternalFunctor(): pass

Here, we use a Functor called "MyExternalFunctor" to compose MyClass. The actual code for MyExternalFunctor is not provided here, but is instead retrieved through GetRegistered(), as described above.

Using this technique, we can reuse Functors within other Functors, and none of the code has to be present on the local system at runtime but can be supplied as needed.

Kind

When using Kind syntax, use eons.inject instead of @method (Python prohibits the use of decorators in Parameter Blocks).

NOTE: Kind allows you to change the name of the External Method, while the decorator does not.

For example:

@eons.kind(eons.Functor)
def MyClass(
    WeCanChangeThisNameNow = eons.inject("MyExternalFunctor")
):
...

Requirements & Notes

1. Circular dependencies are not supported. Because of this, any Functors used to compose more complex classes should be stored in sub-folders in the package or repo_store. Sub-folders will be registered before parent directories. See Self Registration for more info. NOTE: This is now done for you automatically by the Placement system.

2. When calling an External Method, the members of the Functor are not accessible through the function (e.g. MyClass.MyExternalFunctor.DidFunctionSucceed() is not currently supported). To accomplish such behavior, you must currently access the External Method through the methods member. For example, MyClass.methods['MyExternalFunctor'].DidFunctionSucceed().

3. All arguments the External Method accepts are valid to provide to the function. For example, if MyExternalFunctor accepts my_arg as an argument, you can call MyClass.MyExternalFunctor(my_arg='whatever').

Error Resolution for @recoverable Methods

Any method (i.e. member function) of Executor or Functor may be decorated with @recoverable. If a @recoverable method raises an Exception, the Eons error resolution system will engage and attempt to fix the problem.

Because there are a lot of ways an error might arise and be resolved, we don't give you the same freedom of execution as we do with generic GetRegistered() calls. While we use GetRegistered under-the-hood, all possible ErrorResolutions have to be specified ahead of time in your Executor's resolveErrorsWith list member.

If you want to handle errors with your own ErrorResolution, simply call my_executor.resolveErrorsWith.append('my_fix_everything_functor') (paraphrasing).

Creating ErrorResolutions is the same as any other Functor. The only difference is that when you derive from ErrorResolution most of the logic you need has been taken care of for you. You'll just have to implement a Resolve(this) method and call this.ApplyTo(...) in your constructor.
NOTE: all ErrorResolution packages should have the 'resolve_' prefix so that they may be readily identified online.

Check out install_from_repo for an example.

Inheritance Overview

Inheritance allows you to build functionality without duplicating code and is a primary driver for the core programming tenant of never writing the same line twice.

Eons supports several kinds of inheritance. Notably:

• Classic Inheritance
• Implicit Inheritance (i.e. Sequence)
• External Methods (i.e. composition)

Inheritance Style	Relationship	Compiletime	Runtime	Method & Member Accessibility	Type Sharing
Classic	is a	:heavy_check_mark:	:x:	:heavy_check_mark:	:heavy_check_mark:
Implicit	how does	:x:	:heavy_check_mark:	:heavy_check_mark:	:x:
External	has a	:heavy_check_mark:	:x:	:x:	:x:

You are not restricted to a single kind of inheritance. You can, and are encouraged, to use all forms of inheritance in your code!

Logging

Eons attempts to provide a detailed, robust, and pleasant logging experience. We use the logging module, and shim in additional features through our log formatter.

Log Levels

The log level may be set by the verbosity or -v flags. Children and other modules of Eons may employ their own logging levels. However, Eons provides the following levels by default: 0. CRITICAL: only get notified if absolutely necessary.

1. WARNING: get notified about potential problems.
2. INFO: see what's generally going on.
3. DEBUG + urllib3 WARNING: see what's really going on.
4. Empty: reserved for modules.
5. DEBUG: see everything.

Log Features

Indentation

To make logs easier to read, each Functor can be optionally tabbed out as it might be in source code, allowing you to readily see the scope where a log occurs. Each indentation begins with a | character and is followed by a number of spaces equal to the tab width minus one. For example, using a tab width of 2, a log line at the top level would be | ..., while a log at the second level would be | | ....

This feature is enabled by default. To disable it you can set log_indentation to False.

To configure the size of the indentation, you can set log_tab_width to the number of spaces you want to use. For example a tab width of 1 would be just |, while a tab width of 4 would be | .

Aggregation

For security information and event management (SIEM), Eons supports sending logs to a remote endpoint.

This will only be done if a valid repo username and password are provided. If you provide a username and password, but don't want to send your logs to a remote server, you can set log_aggregate to False.

You may also set the log_aggregate_url to wherever you'd like to send your logs. By default, this is set to https://eons.sh/log.

Performance

At Eons LLC, we always prefer functionality over performance. This is the same as the whole "don't prematurely optimize" argument. With that said, optimizing is always good and we try to do it as much as possible.

Please let us know if you are hitting any bottlenecks in this or any of our other libraries!

Design

Functors. Functors...

Functors

Functors are classes (objects) that have an invokable () operator. This allows you to treat them like functions. Eons uses functors (implemented as the Functor class) to provide input, analysis, and output functionalities, which are made simple through classic and implicit inheritance.

Imagine you write 2 functions that take inputs a and b. You can choose to duplicate these inputs, as is the classic means of writing functions: firstFunction(a, b) and secondFunction(a, b). However, with Functors, you can make baseFunctor{inputs=[a,b]} and then simply firstFunctor(baseFunctor) and secondFunctor(baseFunctor), thus creating 2 Functors with identical inputs. The result of firstFunctor(a, b) == firstFunction(a, b) and likewise for the seconds; only, by using Functors we've saved ourselves from duplicating code.

Inputs

For extensibility, all Functors take both an *args and **kwargs argument when called. This allows you to provide arbitrary key word arguments (e.g. key="value") to your objects.

Each functor supports:

• requiredKWArgs - the arguments which the functor cannot be called without.
• staticKWArgs - also required arguments but which are only Fetch()ed once.
• optionalKWArgs - arguments which have a default and do not have to be supplied.

Non-key-word arguments can be specified by appending valid key-word arguments to the argMapping member (list). You cannot directly set the implicit args (how would we know what to call them?).

All values provided in these members will be populated by calls to Fetch(), as described above. This means that if the user calling your Functor does not provide, say their password, it can be automatically looked up in the environment variables.

For other supported features, check out Functor.py

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 this.default.repo.directory 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").

Dynamic error resolutions enables this self registration system to work with inheritance as well. This means that, within downloaded functor, you can from some_module_to_download import my_desired_class to download another.

NOTE: SelfRegistering.RegisterAllClassesInDirectory(...) is depth-first, meaning any sub-folders in the given folder will be loaded before the parent directory. This helps to organize inheritance dependencies, but can be disabled with recurse=False.

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.

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.

Your Very Own Functors

When creating your own Functors, derive from eons.StandardFunctor (unless you know what you're doing). The StandardFunctor just makes your life easier. For example, when extending StandardFunctor, the following utilities become 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):
    ...

These methods take care of logging, some error resolution, and other things that the traditional python solutions fail to address. The source for these methods is available in StandardFunctor.py.

In your Functor, you should set the ____KWArgs members in __init__(this, name) and define the Function(this) and DidFunctionSucceed(this) methods. That's pretty much it. For more advanced configuration, see Functor.py.