Add observer pattern and two decorator pattern examples

pyproject.toml

@@ -2,7 +2,11 @@
 name = "python-samples"
 version = "0.1.0"
 description = "Monorepo for my Python code samples for talks, presentations, workshops, demos."
-dependencies = ["fastapi[uvicorn]>=0.100.0", "uvicorn[standard]>=0.23.1"]
+dependencies = [
+    "fastapi[uvicorn]>=0.100.0",
+    "uvicorn[standard]>=0.23.1",
+    "numpy",
+]
 readme = "README.md"
 requires-python = ">= 3.8"
 

src/essentials/05_patterns/decorator_pattern.py

@@ -0,0 +1,43 @@
+import functools
+import typing
+
+
+def make_bold(func: typing.Callable[..., str]) -> typing.Callable[..., str]:
+    def wrapper(*args, **kwargs):
+        return f"\033[1m{func(*args, **kwargs)}\033[0m"
+    return wrapper
+
+
+def make_cyan(func: typing.Callable[..., str]) -> typing.Callable[..., str]:
+    # https://docs.python.org/3/library/functools.html#functools.wraps
+    @functools.wraps(func)
+    def wrapper(*args, **kwargs):
+        return f"\033[96m{func(*args, **kwargs)}\033[0m"
+    return wrapper
+
+if __name__ == "__main__":
+
+    def greet_raw(name):
+        return f"Hello, {name}!"
+
+    @make_bold
+    def greet_with_decorator(name):
+        return f"Hello, {name}!"
+
+
+    greet_bold = make_bold(greet_raw)
+    greet_cyan = make_cyan(greet_raw)
+
+    text = "Hello, World!"
+
+    print(text)
+    print(greet_raw(text))
+    print(greet_bold(text))
+    print(greet_with_decorator(text))
+    print(greet_cyan(text))
+
+
+    print(greet_bold.__name__)
+    print(greet_cyan.__name__)
+
+    pass

src/essentials/05_patterns/decorator_pattern_2.py

@@ -0,0 +1,79 @@
+import functools
+import inspect
+import pathlib
+import time
+import typing
+from math import log
+
+
+def measure_time(func: typing.Callable[..., typing.Any]) -> typing.Callable[..., typing.Any]:
+    @functools.wraps(func)
+    def wrapper(*args, **kwargs):
+        start = time.time()
+        result = func(*args, **kwargs)
+        end = time.time()
+        print(f"Execution time: {end - start} s")
+        return result
+    return wrapper
+
+
+
+
+
+
+def measure_time_2(log_to_file: bool = False, log_file: str = "_execution_times.log"):
+    def decorator(func: typing.Callable) -> typing.Callable:
+        @functools.wraps(func)
+        def wrapper(*args: typing.Any, **kwargs: typing.Any) -> typing.Any:
+            start_time = time.time()
+            result = func(*args, **kwargs)
+            end_time = time.time()
+            execution_time = end_time - start_time
+
+            file_path = pathlib.Path(inspect.getfile(func)).resolve()
+            line_number = inspect.getsourcelines(func)[1]
+
+            message = f"Function '{func.__name__}' from file '{file_path}:{line_number}' took {execution_time:.4f} seconds to execute."
+
+            if log_to_file:
+                with open(log_file, 'a') as f:
+                    f.write(message + '\n')
+            else:
+                print(message)
+
+            return result
+        return wrapper
+    return decorator
+
+
+if __name__ == "__main__":
+
+    @measure_time
+    def slow_function():
+        import time
+        time.sleep(1)
+        return "Done!"
+
+    @measure_time_2(log_to_file=True, log_file="_slow_functions.txt")
+    def another_slow_function(x: int, y: int) -> int:
+        time.sleep(1.1)
+        return x + y
+
+    @measure_time_2()
+    def my_function():
+        time.sleep(1.2)
+        return "My function"
+
+    @measure_time_2(log_to_file=True)
+    def my_function_2():
+        time.sleep(0.6)
+        return "My function 2"
+
+    print(slow_function())
+    print()
+    print(another_slow_function(1, 2))
+    print()
+    print(my_function())
+    print()
+    print(my_function_2())
+    pass