Data rotation and cleanup in Raspberry Pi - Step-by-Step Execution

Concept Flow - Data rotation and cleanup

Start

↓

Check data size or age

↓

Is data too old or large?

No→Wait or Exit

Yes↓

Rotate data: archive or move old data

↓

Cleanup: delete or compress old files

↓

Log actions

↓

End or repeat

This flow checks if data is too old or large, then rotates and cleans it up to save space and keep things organized.

Execution Sample

Raspberry Pi

import os
import time

if os.path.getsize('log.txt') > 1000:
    os.rename('log.txt', f'log_{int(time.time())}.txt')
    open('log.txt', 'w').close()

This code checks if 'log.txt' is bigger than 1000 bytes, renames it with a timestamp, and creates a new empty 'log.txt'.

Execution Table

Step	Action	Condition	Result	Output
1	Check size of 'log.txt'	Size > 1000?	True	Size is 1500 bytes
2	Rename 'log.txt' to 'log_<timestamp>.txt'	N/A	File renamed	log_1687000000.txt
3	Create new empty 'log.txt'	N/A	File created empty	log.txt size 0 bytes
4	End process	N/A	Cleanup done	Ready for new logs

💡 Data rotated because size exceeded 1000 bytes

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
log.txt size (bytes)	1500	1500	N/A (renamed)	0	0
log file name	'log.txt'	'log.txt'	'log_<timestamp>.txt'	'log.txt'	'log.txt'

Key Moments - 2 Insights

Why do we rename the file before creating a new one?

Renaming preserves the old data by moving it to a new file, so we don't lose logs before starting fresh, as shown in step 2 of the execution table.

What happens if the file size is not greater than 1000?

The code skips renaming and cleanup, so the file stays the same. This is implied by the condition in step 1.

Visual Quiz - 3 Questions

Look at the execution table, what is the size of 'log.txt' after step 3?

A 1500 bytes

B 1000 bytes

C 0 bytes

D File deleted

💡 Hint

Check the 'Result' and 'Output' columns in step 3 of the execution table.

At which step is the old log file renamed?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Action' column to find when renaming happens.

If the file size was 900 bytes, what would happen?

A No action taken

B New empty file created

C File would be renamed

D File deleted

💡 Hint

Refer to the condition in step 1 about size > 1000.

Concept Snapshot

Data rotation and cleanup:
- Check data size or age
- If too large/old, rename or archive data
- Create new empty file or compress old data
- Helps keep storage clean and organized
- Common in log file management on Raspberry Pi

Full Transcript

This example shows how to manage data files on a Raspberry Pi by checking if a file is too large, then renaming it with a timestamp to save old data, and creating a new empty file for fresh data. This process is called data rotation and cleanup. It helps keep storage organized and prevents files from growing too big. The code checks the file size, renames the file if needed, and resets the original file. The execution table traces each step, showing variable changes and actions. This method is useful for managing logs or data files that grow over time.