GCI1066 [Team TREE][2025] - Logging format interpolation

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Added rule GCI1066: For logging format, prefer using `%s` with kwargs instead of builtin formatter `"".format()` or `f""`, that way message formatting will be deferred until it cannot be avoided.
+
 ### Changed
 
 - Correction of various typos in rules documentations

RULES.md

@@ -83,6 +83,8 @@ Some are applicable for different technologies.
 |          | Resize images browser-side                                        | Do not resize images using the HEIGHT and WIDTH attributes of the HTML code. This approach requires transferring these images to their original size, wasting bandwidth and CPU cycles.                                                                                                                                                                                                                                       | [cnumr best practices (3rd edition) BP_034](https://github.com/cnumr/best-practices/blob/main/chapters/BP_034_fr.md)                                                    | 🚫   | 🚫  | 🚧 | 🚫     | 🚫   | 🚫 | 🚀   |
 |          | Modify the DOM when traversing it                                 | Modifying the DOM (Document Object Model) as you traverse it can lead to situations where the loop becomes very resource-intensive, especially CPU cycles.                                                                                                                                                                                                                                                                    | [cnumr best practices (3rd edition) BP_041](https://github.com/cnumr/best-practices/blob/main/chapters/BP_041_fr.md)                                                    | 🚫   | 🚫  | 🚧 | 🚫     | 🚫   | 🚫 | 🚫   |
 |          | Edit DOM elements to make it invisible                            | When an element of the Document Object Model (DOM) needs to be modified by several properties, each change in style or content will generate a repaint or reflow.                                                                                                                                                                                                                                                             | [cnumr best practices (3rd edition) BP_042](https://github.com/cnumr/best-practices/blob/main/chapters/BP_042_fr.md)                                                    | 🚫   | 🚫  | 🚀 | 🚫     | 🚫   | 🚫 | 🚫   |
+| GCI1066  | Logging format interpolation                                      | When logging with formatted string, prefer using `%s` with kwargs, which will be deferred until it cannot be avoided, instead of immediate formatter `.format()` of `f""`.                                                                                                                                                                                                                                                       |                                                                                                                                                                         | 🚫   | 🚫  | 🚫 | 🚀     | 🚫   | 🚫 | 🚫   |
+
 
 ## Rules to be reworked / measured / clarified
 

src/main/rules/GCI1066/GCI1066.json

@@ -0,0 +1,18 @@
+{
+  "title": "Logging Format Interpolation - Avoid using immediate string formatter in logging calls.",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "creedengo",
+    "eco-design",
+    "performance",
+    "python",
+    "logging",
+    "format"
+  ],
+  "defaultSeverity": "Minor"
+}

src/main/rules/GCI1066/python/GCI1066.asciidoc

@@ -0,0 +1,51 @@
+When logging with formatted string, prefer using `%s` and logging kwargs which will be deferred until it cannot be avoided, instead of immediate `.format()` of `f""` interpolation.
+
+== Non Compliant Code Example
+
+[source,python]
+----
+import logging
+logging.basicConfig(level=logging.INFO)
+name = "world"
+logging.debug(f"hello {world}")  # Non Compliant: the replacement will be done immediately but will not be printed because current level is INFO
+----
+
+== Compliant Solution
+
+[source,python]
+----
+import logging
+logging.basicConfig(level=logging.INFO)
+name = "world"
+logging.debug("hello %s", name)  # Compliant: the replacement will be avoided by logging module because it is not necessary
+----
+
+
+== Relevance Analysis
+
+This rule is relevant to logging formatting. Using logging kwargs is more efficient than immediate builtin formatting.
+
+=== Configuration
+
+* Processor: Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz, 4 cores
+* RAM: 8 GB  
+* CO2 Emissions Measurement: Using https://mlco2.github.io/codecarbon/[CodeCarbon]
+
+=== Context
+
+Two approaches were benchmarked:
+- *Non-compliant:* Using logging with `.format()`
+- *Compliant:* Using logging with `%s` and kwargs
+
+=== Impact Analysis
+
+image::result.png[]
+
+== Conclusion
+
+Replacing `f""` and `"".format()` with `%s` and logging kwargs permits to defer template replacement when the log is not displayed.
+
+== References
+
+- https://docs.python.org/3/howto/logging.html#optimization
+- https://pylint.pycqa.org/en/latest/user_guide/messages/warning/logging-format-interpolation.html