Skip to content

Commit 5281c97

Browse files
davidbpdavidbp
committed
feat: add logs
1 parent b91034b commit 5281c97

8 files changed

Lines changed: 257 additions & 0 deletions

File tree

‎python_basics/logging/README.md‎

Lines changed: 176 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,176 @@
1+
2+
# The `logging` module
3+
4+
Logging is means of tracking events that happen during software execution.
5+
6+
The `logging` module provides a set of convenience functions that are meant to be used in differnet scenarios
7+
8+
9+
10+
- **`logging.info()`**: Report events that occur during normal/expected operation of a program.
11+
12+
- **`logging.debug()`**: Report detailed otuput for diagnostic purposes.
13+
14+
- **`logging.warn()`**: Issue a warning due to a runtime event, use this if the situation is avoidable by the user to eliminate the warning.
15+
16+
- **`logging.warning()`**: Issue a warning due to a runtime event, use this if the user cannnot do anything about the situation, the the event should be notted.
17+
18+
- **`logging.error()`**: Report error without raising a python exception.
19+
20+
21+
By default, messages that are not printed (due to the logging level threshold) are simply discarded and are not stored anywhere. The logging module only processes messages that meet or exceed the configured logging level.
22+
23+
24+
25+
### Example 1:
26+
27+
In `ex1.py` one can find the following code
28+
29+
```python
30+
import logging
31+
logging.warning('Warning: check this!') # will print a message to the console
32+
logging.info('Information logged') # will not print anything
33+
```
34+
35+
When running `ex1.py` the user will see:
36+
37+
```python
38+
WARNING:root:Warning: check this!
39+
```
40+
41+
Note: Nothing about the `logging.info()` message is displayed..
42+
43+
Without configuration, only messages at WARNING level or higher will be displayed. The logging levels in order of increasing severity are:
44+
45+
```python
46+
DEBUG (10) < INFO (20) < WARNING (30) < ERROR (40) < CRITICAL (50)
47+
```
48+
49+
Now in example 2 we will simply add `logging.basicConfig(level=logging.INFO)` to the code so that `INFO` messages are shown.
50+
51+
52+
53+
### Example 2: Chaning logging displayed information
54+
55+
One can change what is printed in the terminal when running a script updating the level of `logging` using `logging.basicConfig(level=logging.LEVEL)`
56+
where `LEVEL` can be a string from `[]`.
57+
58+
For example, if we add `LEVEL=INFO`, as one can see in `ex2.py`
59+
60+
61+
```python
62+
import logging
63+
64+
logging.basicConfig(level=logging.INFO)
65+
66+
logging.warning('Warning: check this!') # will be printed because `logging.basicConfig(level=logging.INFO)`
67+
logging.info('Information logged') # will be printed
68+
```
69+
70+
When running `python ex2.py` the user will see:
71+
72+
```
73+
WARNING:root:Warning: check this!
74+
INFO:root:Information logged
75+
```
76+
77+
Which includes the `INFO` details that did not appear in `ex1.py`.
78+
79+
80+
81+
### Example 3: Storing some logged information with a file handler with **`logging.FileHandler`**
82+
83+
84+
The code in `ex3.py` shows how to add a handler that stores to disk the logged messages.
85+
86+
- To print in the console `console_handler = logging.StreamHandler()` is used.
87+
88+
- To print in a file `file_handler = logging.FileHandler(log_file)` is used.
89+
90+
91+
```python
92+
import logging
93+
94+
# Create and configure handlers
95+
console_handler = logging.StreamHandler()
96+
console_handler.setLevel(logging.WARNING) # Console shows only WARNING and above
97+
98+
file_handler = logging.FileHandler('all_messages.log')
99+
file_handler.setLevel(logging.DEBUG) # File stores everything
100+
101+
# Configure the root logger
102+
logging.basicConfig(
103+
level=logging.DEBUG, # Allow processing of all messages
104+
format='%(asctime)s - %(levelname)s - %(message)s',
105+
handlers=[console_handler, file_handler]
106+
)
107+
108+
# Now test all levels
109+
logging.debug("Debug message - in file only")
110+
logging.info("Info message - in file only")
111+
logging.warning("Warning message - in both file and console")
112+
logging.error("Error message - in both file and console")
113+
```
114+
115+
116+
After running this:
117+
118+
- Console output will show only WARNING and ERROR messages
119+
120+
- The file `ex3__all_messages.log` will contain ALL messages (DEBUG, INFO, WARNING, and ERROR)
121+
122+
123+
124+
125+
### Example 4: Storing some logged information with a file handler with **`logging.FileHandler`** and adding time into the logged filename
126+
127+
128+
Example `ex4.py` shows how to create a logger that stores the logged items to disk with **`logging.FileHandler`**. The example also has a logger that takes care of printing to the console (we can use more than one logger!).
129+
130+
- To print in the console `console_handler = logging.StreamHandler()` is used.
131+
132+
- To print in a file `file_handler = logging.FileHandler(log_file)` is used.
133+
134+
135+
```python
136+
import logging
137+
import os
138+
from datetime import datetime
139+
140+
# Create 'logged_messages' directory if it doesn't exist
141+
log_dir = 'logged_messages'
142+
if not os.path.exists(log_dir):
143+
os.makedirs(log_dir)
144+
145+
# Create log file path with timestamp
146+
timestamp = datetime.now().strftime('%Y_%m_%d_%H_%M_%S')
147+
log_file = os.path.join(log_dir, f'ex4__all_messages__{timestamp}.log')
148+
149+
# Create and configure handlers
150+
console_handler = logging.StreamHandler()
151+
console_handler.setLevel(logging.WARNING) # Console shows only WARNING and above
152+
153+
file_handler = logging.FileHandler(log_file)
154+
file_handler.setLevel(logging.INFO) # File stores INFO and above (changed from DEBUG)
155+
156+
# Configure the root logger
157+
logging.basicConfig(
158+
level=logging.DEBUG, # Keep DEBUG as lowest level to allow all messages to be processed
159+
format='%(asctime)s - %(levelname)s - %(message)s',
160+
handlers=[console_handler, file_handler]
161+
)
162+
163+
# Test all logging levels
164+
logging.debug("Debug message - won't be stored anywhere")
165+
logging.info("Info message - in file only")
166+
logging.warning("Warning message - in both file and console")
167+
logging.error("Error message - in both file and console")
168+
```
169+
170+
171+
After running this:
172+
173+
- Console output will show only WARNING and ERROR messages
174+
175+
- The file `ex4__all_messages__2025_02_25_11_20_04.log` will contain messages INFO, WARNING, and ERROR.
176+

‎python_basics/logging/ex0.py‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
print("hello there ex0")

‎python_basics/logging/ex1.py‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,4 @@
1+
import logging
2+
3+
logging.warning('Warning: check this!') # will print a message to the console
4+
logging.info('Information logged') # will not print anything

‎python_basics/logging/ex2.py‎

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,6 @@
1+
import logging
2+
3+
logging.basicConfig(level=logging.INFO)
4+
5+
logging.warning('Warning: check this!') # will be printed because `logging.basicConfig(level=logging.INFO)`
6+
logging.info('Information logged') # will be printed

‎python_basics/logging/ex3.py‎

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,31 @@
1+
import logging
2+
import os
3+
from datetime import datetime
4+
5+
# Create 'logged_messages' directory if it doesn't exist
6+
log_dir = 'logged_messages'
7+
if not os.path.exists(log_dir):
8+
os.makedirs(log_dir)
9+
10+
# Create log file path
11+
log_file = os.path.join(log_dir, 'ex3__all_messages.log')
12+
13+
# Create and configure handlers
14+
console_handler = logging.StreamHandler()
15+
console_handler.setLevel(logging.WARNING) # Console shows only WARNING and above
16+
17+
file_handler = logging.FileHandler(log_file)
18+
file_handler.setLevel(logging.DEBUG) # File stores everything
19+
20+
# Configure the root logger
21+
logging.basicConfig(
22+
level=logging.DEBUG, # Allow processing of all messages
23+
format='%(asctime)s - %(levelname)s - %(message)s',
24+
handlers=[console_handler, file_handler]
25+
)
26+
27+
# Now test all levels
28+
logging.debug("Debug message - in file only")
29+
logging.info("Info message - in file only")
30+
logging.warning("Warning message - in both file and console")
31+
logging.error("Error message - in both file and console")

‎python_basics/logging/ex4.py‎

Lines changed: 32 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,32 @@
1+
import logging
2+
import os
3+
from datetime import datetime
4+
5+
# Create 'logged_messages' directory if it doesn't exist
6+
log_dir = 'logged_messages'
7+
if not os.path.exists(log_dir):
8+
os.makedirs(log_dir)
9+
10+
# Create log file path with timestamp
11+
timestamp = datetime.now().strftime('%Y_%m_%d_%H_%M_%S')
12+
log_file = os.path.join(log_dir, f'ex4__all_messages__{timestamp}.log')
13+
14+
# Create and configure handlers
15+
console_handler = logging.StreamHandler()
16+
console_handler.setLevel(logging.WARNING) # Console shows only WARNING and above
17+
18+
file_handler = logging.FileHandler(log_file)
19+
file_handler.setLevel(logging.INFO) # File stores INFO and above (changed from DEBUG)
20+
21+
# Configure the root logger
22+
logging.basicConfig(
23+
level=logging.DEBUG, # Keep DEBUG as lowest level to allow all messages to be processed
24+
format='%(asctime)s - %(levelname)s - %(message)s',
25+
handlers=[console_handler, file_handler]
26+
)
27+
28+
# Test all logging levels
29+
logging.debug("Debug message - won't be stored anywhere")
30+
logging.info("Info message - in file only")
31+
logging.warning("Warning message - in both file and console")
32+
logging.error("Error message - in both file and console")

‎python_basics/logging/logged_messages/ex3__all_messages.log‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,4 @@
1+
2025-02-25 11:19:18,678 - DEBUG - Debug message - in file only
2+
2025-02-25 11:19:18,678 - INFO - Info message - in file only
3+
2025-02-25 11:19:18,678 - WARNING - Warning message - in both file and console
4+
2025-02-25 11:19:18,678 - ERROR - Error message - in both file and console

‎python_basics/logging/logged_messages/ex4__all_messages__2025_02_25_11_20_04.log‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
2025-02-25 11:20:04,538 - INFO - Info message - in file only
2+
2025-02-25 11:20:04,538 - WARNING - Warning message - in both file and console
3+
2025-02-25 11:20:04,538 - ERROR - Error message - in both file and console

0 commit comments

Comments
 (0)