Regular Expressions

Task 1: Log File IP and Timestamp Extractor

Create a script named log_regex_task.py inside your lesson_43 folder:

• Import re and define a log string containing multiple entries with timestamps, severity levels, and IP addresses.
• Pre-compile a RegEx pattern with Named Groups: (?P\d{4}-\d{2}-\d{2}), (?PINFO|WARN|ERROR), (?P\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).
• Iterate through lines using re.finditer() and display extracted dictionary records via .groupdict().

Task 2: Pattern-Matched Credit Card Masker and Validator

Create a script named card_masker_task.py:

• Define a function sanitize_credit_card(card_str: str) -> str.
• Use re.sub() to replace all spaces and hyphens with empty strings.
• Write a match-case dispatcher to validate card digits length using re.match(r"^\d{16}$", clean_card) and return a masked string format: "****-****-****-1234".
• Test function with valid formatted cards, unformatted raw digits, and invalid inputs.

Task 3: Master Review Capstone Project — Production Enterprise RegEx Parsing & Telemetry OS (`regex_parser_os.py`)

Create a script named regex_parser_os.py inside your lesson_43 folder. This assignment tests and integrates **ALL concepts learned across Lessons 1 through 43**.

Project Architectural Requirements Specification:

1. Regular Expressions & Pattern Extraction (Lesson 43):
   • Pre-compile domain RegEx patterns with Named Groups for parsing emails, phone numbers, transaction IDs, and IP addresses.
   • Perform text sanitization and data masking using re.sub().
   • Use re.finditer() for low-memory lazy extraction streams.
2. Type Hints, Generics & Static Safety (Lesson 42):
   • Apply explicit modern type annotations (X | Y, list[str], dict[str, Any]) throughout all functions and classes.
   • Define domain TypeAlias definitions and Generic Response Envelopes.
3. Metaprogramming, Closures & Decorators (Lessons 40-41):
   • Build function factories generating customized RegEx validation closures.
   • Build a 3-level configurable decorator audit_pattern_execution(level="INFO") with @functools.wraps.
4. Iterators, Generators & Functional Processing (Lesson 39):
   • Implement generator functions streaming log file lines lazily with $O(1)$ memory footprint.
5. Full OOP Architecture (Lessons 32-38):
   • Define abstract base class BasePatternParser(ABC) and concrete Data Classes ParsedLogRecord and SecurityAlert.
   • Build composite manager RegExParserOS composing storage drivers and custom context managers.
6. Observability & Fault Tolerance (Lessons 29-31):
   • Set up multi-handler logging to console and regex_os.log file.
   • Incorporate developer assertions (assert) verifying pattern match bounds.
   • Define custom exception hierarchy (RegexParsingError, PatternMismatchError).
7. Context Managers & Persistence Layer (Lessons 27-30):
   • Use custom class-based context manager ParserVaultLock to manage persistent database lock files.
   • Persist JSON records to parsed_db.json and export CSV audit reports to regex_audit.csv using pathlib.Path.
8. Nested Collections & Comprehensions (Lessons 21-26):
   • Maintain in-memory registry dictionaries mapping IDs to Data Class Instances.
   • Use List and Dictionary Comprehensions to clean and transform records.
9. Advanced Function Parameters & Scope (Lessons 15-17):
   • Structure logic into pure modular functions with type hints, docstrings, early return Guard Clauses, and *args / **kwargs logging.
10. Indefinite & Definite Loops (Lessons 13-14):
    • Run the interactive CLI interface inside a continuous while True menu loop.
    • Iterate through output reports using for loops with enumerate() and .items().
11. Pattern Matching CLI Dispatcher (Lesson 12):
    • Process user CLI command tokens inside a match-case block with RegEx pattern guards:
      • case ["PARSE", "EMAIL", raw_email] → Parse email using named groups RegEx and persist.
      • case ["MASK", "CARD", raw_card] → Redact card number using re.sub() and output.
      • case ["STREAM", filename] → Stream file lines lazily and apply RegEx pattern extraction.
      • case ["EXPORT", "CSV"] → Export parsed database state to CSV.
      • case ["EXIT" | "QUIT"] → Terminate session safely using a sentinel flag.
      • case _ → Output command error message.
12. Conditionals, Formatting & Foundations (Lessons 1-11):
    • Sanitize all inputs using .strip() and .upper().
    • Format tabular reports using f-strings with field width alignment specifiers (:<15, :>10) and clear visual borders.