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tianxuan/analysis/type_classifier.py
T

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Python

"""Data type classifier for column-level type inference.
Provides :class:`DataType` enumeration and functions to classify Polars
columns based on name heuristics and value sampling.
Typical usage::
from analysis.type_classifier import classify_column, classify_schema, DataType
# Single column
dtype = classify_column('src_ip', series, config_type='ipv4')
# Full schema
type_map = classify_schema(lazyframe, config_overrides={'src_ip': 'ipv4'})
"""
from __future__ import annotations
import re
from enum import Enum
import polars as pl
# ---------------------------------------------------------------------------
# DataType enumeration
# ---------------------------------------------------------------------------
class DataType(Enum):
"""Enumerated column types recognised by the classifier engine."""
INT = 1
FLOAT = 2
ENUM = 3
HEX = 4
URL = 5
IPv4 = 6
LAT_LON = 7
TIMESTAMP = 8
BOOL_ENUM = 9
STRING = 10
# ---------------------------------------------------------------------------
# Detection patterns (raw strings for regex)
# ---------------------------------------------------------------------------
HEX_PATTERN = r'^[0-9a-f]{2}(?:\s[0-9a-f]{2})*$'
"""Matches ``"0e a6 3f"``, ``"ab cd ef"`` etc. (space-separated hex pairs)."""
URL_PATTERN = r'^https?://'
"""Matches URLs starting with ``http://`` or ``https://``."""
IPv4_PATTERN = r'^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$'
"""Matches ``"192.168.1.1"`` style IPv4 addresses."""
MAC_PATTERN = r'^([0-9A-Fa-f]{2}[:.-]){5}[0-9A-Fa-f]{2}$'
"""Matches MAC addresses with ``:``, ``-``, or ``.`` separators."""
BOOL_ENUM_VALUES = (
'', ' ', '+', '-', '0', '1',
'true', 'false', 'yes', 'no', 't', 'f',
)
"""String values considered boolean / binary indicators."""
LAT_LON_NAMES = ('lat', 'latitude', 'lon', 'lng', 'longitude')
# Name-to-type heuristics (checked after config override, before values)
_NAME_TYPE_MAP: list[tuple[re.Pattern, DataType]] = [
# User column names - EXACT match only (no generic fuzzy patterns)
# IPv4 columns
(re.compile(r'^:ips$|^:ipd$|^server.ip$|^client.ip$', re.I), DataType.IPv4),
# ENUM columns
(re.compile(r'^:prs$|^:prd$', re.I), DataType.ENUM),
(re.compile(r'^(?:scnt|dcnt|cnrs|isrs|1ipp|4dbn)$', re.I), DataType.ENUM),
(re.compile(r'^0ver$', re.I), DataType.ENUM),
# FLOAT columns
(re.compile(r'^4dur$|^8ses$|^2tmo$|^0rnt$', re.I), DataType.FLOAT),
# INT columns
(re.compile(r'^4ksz$|^8ack$|^8ppk$|^row$', re.I), DataType.INT),
# HEX columns
(re.compile(r'^0cph$|^0crv$', re.I), DataType.HEX),
# TIMESTAMP columns
(re.compile(r'^8dbd$|^time$|^timestamp$', re.I), DataType.TIMESTAMP),
# Dot-notation suffixes for lat/lon (e.g. :ips.latd, :ipd.lond)
(re.compile(r'\.latd$', re.I), DataType.LAT_LON),
(re.compile(r'\.lond$', re.I), DataType.LAT_LON),
# Dot-notation STRING suffixes (e.g. :ips.ispn, :ipd.city)
(re.compile(r'\.(ispn|orgn|city)$', re.I), DataType.STRING),
# Standalone string columns - exact match
(re.compile(r'^(?:cnam|snam|tabl|name|0rnd|source.node|ecdhe.named.curve)$', re.I), DataType.STRING),
]
# Mapping from config.yaml type strings to DataType
_CONFIG_TYPE_MAP: dict[str, DataType] = {
'int': DataType.INT,
'float': DataType.FLOAT,
'enum': DataType.ENUM,
'hex': DataType.HEX,
'url': DataType.URL,
'ipv4': DataType.IPv4,
'lat_lon': DataType.LAT_LON,
'timestamp': DataType.TIMESTAMP,
'bool_enum': DataType.BOOL_ENUM,
'string': DataType.STRING,
}
# ---------------------------------------------------------------------------
# Column classification (single column)
# ---------------------------------------------------------------------------
def _name_to_type(name: str) -> DataType | None:
"""Match column name against known heuristics.
Returns a :class:`DataType` if the name matches strongly, otherwise
``None`` (fall through to value-based detection).
"""
for pattern, dtype in _NAME_TYPE_MAP:
if pattern.search(name):
return dtype
return None
def _is_port_value(v: str) -> bool:
"""Check if *v* is an integer string in the registered port range (1-65535)."""
try:
n = int(v)
return 1 <= n <= 65535
except ValueError:
return False
def _can_float(v: str) -> bool:
"""Return ``True`` when *v* can be parsed as a Python float."""
try:
float(v)
return True
except ValueError:
return False
def _values_to_type(series: pl.Series) -> DataType:
"""Infer column type by sampling non-null values.
Detection order: IPv4 → MAC guard → HEX → URL → PORT → BOOL_ENUM
→ LAT_LON → ENUM → FLOAT → STRING
"""
dtype = series.dtype
# Boolean dtype ──────────────────────────────────────────────────────
if dtype == pl.Boolean:
return DataType.BOOL_ENUM
# Numeric dtypes ─────────────────────────────────────────────────────
if dtype in (pl.Float32, pl.Float64):
# Check LAT_LON possibility before returning FLOAT
non_null = series.drop_nulls()
if len(non_null) > 0:
sample = non_null.head(100)
sample_strs = [str(v).strip().lower() for v in sample]
non_blank = [v for v in sample_strs if v not in ('', ' ', '+', '-')]
if non_blank:
try:
floats = [float(v) for v in non_blank]
max_abs = max(abs(f) for f in floats)
if (
all(-180 <= f <= 180 for f in floats)
and any('.' in v for v in non_blank)
and max_abs > 10
):
return DataType.LAT_LON
except ValueError:
pass
return DataType.FLOAT
if dtype in (pl.Int8, pl.Int16, pl.Int32, pl.Int64,
pl.UInt8, pl.UInt16, pl.UInt32, pl.UInt64):
return DataType.INT
# String / categorical types ─────────────────────────────────────────
non_null = series.drop_nulls()
if len(non_null) == 0:
return DataType.STRING
sample = non_null.head(100)
# Convert all to string representations for pattern matching
sample_strs = [str(v).strip().lower() for v in sample]
# ── 1. IPv4 detection ──────────────────────────────────────────────
if all(re.match(IPv4_PATTERN, v) for v in sample_strs):
if all(_valid_ip_octets(v) for v in sample_strs):
return DataType.IPv4
# ── 2. MAC guard (skip HEX if values look like MAC addresses) ──────
is_mac = all(re.match(MAC_PATTERN, v) for v in sample_strs)
# ── 3. HEX detection ───────────────────────────────────────────────
if not is_mac and all(re.match(HEX_PATTERN, v) for v in sample_strs):
return DataType.HEX
# ── 4. URL detection ───────────────────────────────────────────────
if all(re.match(URL_PATTERN, v) for v in sample_strs):
return DataType.URL
# ── 5. PORT detection → ENUM ───────────────────────────────────────
if all(_is_port_value(v) for v in sample_strs):
return DataType.ENUM
# ── 6. BOOL_ENUM detection ─────────────────────────────────────────
if all(v in BOOL_ENUM_VALUES for v in sample_strs):
return DataType.BOOL_ENUM
# ── 7. LAT_LON detection (value-based) ──────────────────────────────
non_blank = [v for v in sample_strs if v not in ('', ' ', '+', '-')]
if non_blank:
try:
floats = [float(v) for v in non_blank]
max_abs = max(abs(f) for f in floats)
if (
all(-180 <= f <= 180 for f in floats)
and any('.' in v for v in non_blank)
and max_abs > 10
):
return DataType.LAT_LON
except ValueError:
pass
# ── 8. ENUM detection (few unique values) ──────────────────────────
unique_count = non_null.n_unique()
if unique_count < 20:
return DataType.ENUM
# ── 9. FLOAT detection (>80 % can float) ───────────────────────────
float_count = sum(1 for v in sample_strs if _can_float(v))
if float_count / len(sample_strs) > 0.8:
# Guard: values with leading "+"/"-" (e.g., "+5", "-abc") that
# happen to parse as float should not force a FLOAT classification
# when non-float values exist in the column. This catches string
# columns where a "+" prefix is used as a text marker (phone codes,
# IDs, error codes) rather than a numeric sign.
if any(v.startswith('+') or v.startswith('-') for v in sample_strs):
if float_count < len(sample_strs):
return DataType.STRING
return DataType.FLOAT
return DataType.STRING
def _valid_ip_octets(ip_str: str) -> bool:
"""Check that each octet in an IPv4 string is 0-255."""
parts = ip_str.split('.')
if len(parts) != 4:
return False
for p in parts:
try:
n = int(p)
if n < 0 or n > 255:
return False
except ValueError:
return False
return True
def classify_column(
name: str,
series: pl.Series,
config_type: str | None = None,
) -> DataType:
"""Classify a single column based on its *name* and *series* values.
Priority
--------
1. **config_type** — user override from ``config.yaml``.
If provided (e.g. ``'ipv4'``), returns the corresponding
:class:`DataType` immediately.
2. **Value-based** pattern matching — samples up to 100 non-null
values and tests against IPv4 → HEX → URL → PORT → BOOL_ENUM
→ LAT_LON → ENUM → FLOAT in order.
3. **Name-based** heuristics — only consulted when value-based
detection returned ``STRING`` (i.e. no value pattern matched).
Parameters
----------
name:
Column name (used for name-based heuristics).
series:
Polars :class:`Series` containing the column's data.
config_type:
Optional user override (case-insensitive, matched to
:data:`_CONFIG_TYPE_MAP`).
Returns
-------
DataType
"""
# 1. Config override (highest priority)
if config_type is not None:
mapped = _CONFIG_TYPE_MAP.get(config_type.lower().strip())
if mapped is not None:
return mapped
# 2. Value-based sampling
result = _values_to_type(series)
# 3. Name-based heuristics (only when values returned STRING)
if result == DataType.STRING:
name_match = _name_to_type(name)
if name_match is not None:
return name_match
return result
# ---------------------------------------------------------------------------
# Schema classification (all columns)
# ---------------------------------------------------------------------------
def classify_schema(
lf: pl.LazyFrame,
config_overrides: dict[str, str] | None = None,
) -> dict[str, DataType]:
"""Classify all columns in a :class:`LazyFrame`.
Parameters
----------
lf:
A Polars :class:`LazyFrame` whose columns to classify.
config_overrides:
Optional mapping of ``{col_name: type_string}`` from a
``config.yaml`` ``columns:`` section. These take highest
priority (see :func:`classify_column`).
Returns
-------
dict[str, DataType]
Mapping from column name to inferred :class:`DataType`.
"""
config_overrides = config_overrides or {}
df_sample = lf.collect(streaming=True)
result: dict[str, DataType] = {}
for col_name in df_sample.columns:
config_type = config_overrides.get(col_name)
result[col_name] = classify_column(
name=col_name,
series=df_sample[col_name],
config_type=config_type,
)
return result