[sc-28135] Redact literal values in CASE clauses (#955)

metaphor/common/docs/process_query.md

@@ -7,6 +7,8 @@ process_query:
   redact_literals:
     where_clauses: <true | false>  # Whether to redact all literal values in WHERE clauses. Default is `false`.
 
+    case_clauses: <true | false>  # Whether to redact all literal values in CASE clauses. Default is `false`.
+
     when_not_matched_insert_clauses: <true | false>  # Whether to redact literal values in WHEN NOT MATCHED INSERT clauses. If set to `True`, all literal values will be redacted to a predefined string value. Default is `false`.
 
     placeholder_literal: <placeholder literal>  # The redacted values will be replaced by this placeholder string. Default is '<REDACTED>'.

metaphor/common/sql/process_query/config.py

@@ -16,6 +16,11 @@ class RedactPIILiteralsConfig:
     Whether to redact literal values in WHERE clauses. If set to `True`, all literal values will be redacted to a predefined string value.
     """
 
+    case_clauses: bool = False
+    """
+    Whether to redact literal values in CASE clauses. If set to `True`, all literal values will be redacted to a predefined string value.
+    """
+
     when_not_matched_insert_clauses: bool = False
     """
     Whether to redact literal values in WHEN NOT MATCHED INSERT clauses. If set to `True`, all literal values will be redacted to a predefined string value.

metaphor/common/sql/process_query/process_query.py

@@ -21,6 +21,14 @@ def _redact_literal_values_in_where_clauses(
             lit.args["this"] = config.redact_literals.placeholder_literal
 
 
+def _redact_literal_values_in_case_clauses(
+    expression: Expression, config: ProcessQueryConfig
+) -> None:
+    for case in expression.find_all(exp.Case):
+        for lit in case.find_all(exp.Literal):
+            lit.args["this"] = config.redact_literals.placeholder_literal
+
+
 def _redact_literal_values_in_when_not_matched_insert_clauses(
     expression: Expression,
     config: ProcessQueryConfig,
@@ -90,6 +98,9 @@ def process_query(
     if config.redact_literals.where_clauses:
         _redact_literal_values_in_where_clauses(expression, config)
 
+    if config.redact_literals.case_clauses:
+        _redact_literal_values_in_case_clauses(expression, config)
+
     if config.redact_literals.when_not_matched_insert_clauses:
         _redact_literal_values_in_when_not_matched_insert_clauses(expression, config)
 

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "metaphor-connectors"
-version = "0.14.79"
+version = "0.14.80"
 license = "Apache-2.0"
 description = "A collection of Python-based 'connectors' that extract metadata from various sources to ingest into the Metaphor app."
 authors = ["Metaphor <[email protected]>"]

tests/common/sql/process_query/test_process_query.py

@@ -8,6 +8,7 @@
 config = ProcessQueryConfig(
     redact_literals=RedactPIILiteralsConfig(
         where_clauses=True,
+        case_clauses=True,
         when_not_matched_insert_clauses=True,
     ),
     ignore_insert_values_into=True,
@@ -163,3 +164,29 @@ def test_merge_insert_when_not_matched():
         processed
         == "MERGE INTO TargetProducts AS Target USING SourceProducts AS Source ON Source.ProductID = Target.ProductID WHEN NOT MATCHED THEN INSERT (ProductID, ProductName, Price) VALUES (<REDACTED>, '<REDACTED>', <REDACTED>) WHEN MATCHED THEN UPDATE SET Target.ProductName = Source.ProductName, Target.Price = Source.Price"
     )
+
+
+def test_redact_where_clauses():
+    sql = """
+INSERT INTO target_table (first_name, last_name, email, status)
+SELECT
+    first_name,
+    last_name,
+    email,
+    CASE
+        WHEN age < 18 THEN 'Minor'
+        WHEN age >= 18 AND age < 65 THEN 'Adult'
+        ELSE 'Senior'
+    END as status
+FROM source_table
+WHERE email IS NOT NULL;
+    """
+    processed = process_query(
+        sql,
+        DataPlatform.SNOWFLAKE,
+        config,
+    )
+    assert (
+        processed
+        == "INSERT INTO target_table (first_name, last_name, email, status) SELECT first_name, last_name, email, CASE WHEN age < <REDACTED> THEN '<REDACTED>' WHEN age >= <REDACTED> AND age < <REDACTED> THEN '<REDACTED>' ELSE '<REDACTED>' END AS status FROM source_table WHERE NOT email IS NULL"
+    )