Calculator

This presentations goal it to introduce the features of the Calculator and how to configure it.

The challenge

I want calculate with field values.

from this:

document = {
    'message': {
        "time_in_ms": 0.333
        }
    }

to this:

expected = {
    'message': {
        "time_in_ns": 333000
        }
    }

Create rule and processor

create the rule:

import sys
sys.path.append("../../../../../")
import tempfile
from pathlib import Path

rule_yaml = """---
filter: "message.time_in_ms"
calculator:
  target_field: message.time_in_ns
  calc: trunc(${message.time_in_ms} * 10e5)
  delete_source_fields: true
"""

rule_path = Path(tempfile.gettempdir()) / "calculator"
rule_path.mkdir(exist_ok=True)
rule_file = rule_path / "calculation.yml"
rule_file.write_text(rule_yaml)

153

create the processor config:

processor_config = {
    "mycalculator":{
        "type": "calculator",
        "rules": [str(rule_path), "/dev"],
        }
    }

create the processor with the factory:

from unittest import mock
from logprep.factory import Factory

mock_logger = mock.MagicMock()
calculator = Factory.create(processor_config)
calculator

calculator

Process event

from copy import deepcopy
mydocument = deepcopy(document)


print(f"before: {mydocument}")
calculator.process(mydocument)
print(f"after: {mydocument}")
print(mydocument == expected)

before: {'message': {'time_in_ms': 0.333}}
after: {'message': {'time_in_ns': 333000}}
True