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Python Engine

ZEN Engine is built as embeddable BRE for your Rust, NodeJS, Go or Python applications.

Installation​

pip install zen-engine

Usage​

To execute a simple decision you can use the code below.

import zen

# Example filesystem content, it is up to you how you obtain content
with open("./jdm_graph.json", "r") as f:
  content = f.read()

engine = zen.ZenEngine()

decision = engine.create_decision(content)
result = decision.evaluate({"input": 15})

Loaders​

For more advanced use cases where you want to load multiple decisions and utilise graphs you can build loaders.

import zen

def loader(key):
    with open("./jdm_directory/" + key, "r") as f:
        return f.read()

engine = zen.ZenEngine({"loader": loader})
result = engine.evaluate("jdm_graph1.json", {"input": 5})

or

...

engine = zen.ZenEngine({"loader": loader})
decision = engine.get_decision("jdm_graph1.json")
result = decision.evaluate({"input": 5})

When engine.evaluate is invoked it will call loader and pass a key expecting a content of the JDM decision graph. In the case above we will assume file jdm_directory/jdm_graph1.json exists.

Similar to this example you can also utilise loader to load from different places, for example from REST API, from S3, Database, etc.

Evaluate expressions​

You may also evaluate singular ZEN Expressions.

import zen

zen.evaluate_expression("1 + 1") # 2
zen.evaluate_expression("a + b", { "a": 10, "b": 20 }) # 30

zen.evaluate_unary_expression("> 10", { "$": 5 }) # false 
zen.evaluate_unary_expression("> 10", { "$": 15 }) # true