From ce1bebaf18e3f3a15e604922ffe8bbf70822dce3 Mon Sep 17 00:00:00 2001 From: mikysett Date: Wed, 8 Feb 2023 16:40:34 +0000 Subject: [PATCH] feat(backup_manager): add new exercise subject for quest 8 scripting piscine --- subjects/devops/backup_manager/README.md | 116 +++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 subjects/devops/backup_manager/README.md diff --git a/subjects/devops/backup_manager/README.md b/subjects/devops/backup_manager/README.md new file mode 100644 index 000000000..0e5aa17fc --- /dev/null +++ b/subjects/devops/backup_manager/README.md @@ -0,0 +1,116 @@ +## Backup manager + +### Instructions + +You will create two scripts that will manage and perform scheduled backups. + +#### First script: backup_manager.py + +The script `backup_manager.py` will orchestrate the backup service and if necessary update the file `backup_schedules.txt`. In order to do so it will accept the following command-line arguments: + +- `start`: run `backup_service.py` in the background. +- `stop`: stop the process `backup_service.py`. +- `create [schedule]`: add a new backup schedule in `backup_schedules.txt`. +- `delete [index]`: delete the backup schedule at line `index` (starting by 0) in `backup_schedules.txt`. +- `list`: print the scheduled backups in `backup_schedules.txt`, adding an index before each schedule. +- `backups`: list the backups files in `./backups`. + +#### Second script: backup_service.py + +The script `backup_service.py` will check the schedules in `backup_schedules.txt` and perform the daily backups at the proper time. + +- The service will run in an infinite loop. +- On every cycle of the loop the service will check the schedules. +- The service will perform the backup if the current time (hour and minute) matches the time of the schedule. +- The format of the schedules is `path_to_save;time(hh:mm);backup_name`. +- The backups will be saved in `./backups`. +- The backups will be a compressed file (`.tar`) for the `path_to_save` directory. + +> At the end of each loop it would be wise to make the service sleep for about 45 seconds to save processor cycles. + +### Logs and error handling + +Both scripts will have to use `try` and `except` to handle errors. +All actions and errors should be logged into a specific file in the `./log` directory. + +- `backup_manager.py` will log into `./logs/backup_manager.log`. +- `backup_service.py` will log into `./logs/backup_service.log`. + +You can choose to phrase your logs as you prefer, however it would be smart to start with a timestamp and try to be as specific as you can. + +### Usage + +Here is a little script to show how the backup system should work: + +```bash +echo "--> Create 3 new schedules" +python3 ./backup_manager.py create "test;16:07;backup_test" +python3 ./backup_manager.py create "test1;16:07;personal_data" +python3 ./backup_manager.py create "test2;16:07;office_docs" +echo "--> Try to add a malformed schedule" +python3 ./backup_manager.py create "test;" +echo "--> Instruction list" +python3 ./backup_manager.py list + +python3 ./backup_manager.py start +python3 ./backup_manager.py stop + +echo "--> Instruction backups" +python3 ./backup_manager.py backups + +echo "--> Content of the directory" +ls +echo "--> cat on ./logs/backup_manager.log" +cat ./logs/backup_manager.log +echo "--> cat on ./logs/backup_service.log" +cat ./logs/backup_service.log +echo "--> Content of ./backups" +ls ./backups +``` + +The output of this script should be similar to the following: + +```console +--> Create 3 new schedules +--> Try to add a malformed schedule +--> Instruction list +0: test;16:07;backup_test +1: test1;16:07;personal_data +2: test2;16:07;office_docs +--> Instruction backups +personal_data.tar +office_docs.tar +backup_test.tar +--> Content of the directory +backup_manager.py backups backup_schedules.txt backup_service.py logs +--> cat on ./logs/backup_manager.log +[08/02/2023 16:07] New schedule added: test;16:07;backup_test +[08/02/2023 16:07] New schedule added: test1;16:07;personal_data +[08/02/2023 16:07] New schedule added: test2;16:07;office_docs +[08/02/2023 16:07] Error: malformed schedule: test; +[08/02/2023 16:07] Show schedules list +[08/02/2023 16:07] backup_service started +[08/02/2023 16:07] backup_service stopped +[08/02/2023 16:07] Show backups list +--> cat on ./logs/backup_service.log +[08/02/2023 16:07] Backup done for test in backups/backup_test.tar +[08/02/2023 16:07] Backup done for test1 in backups/personal_data.tar +[08/02/2023 16:07] Backup done for test2 in backups/office_docs.tar +--> Content of ./backups +backup_test.tar office_docs.tar personal_data.tar +``` + +### Hints + +- To run a script from another python script you could use `subprocess.Popen` with the flag `start_new_session=True`. +- To kill a process you should find its process id and call `os.kill`. +- Play with the command `ps -A -f`, it will show a list of all active processes with the arguments attached to them and their process ids. +- The standard library `tarfile` is very useful when trying to work with archives. +- This starts to be quite a big project, try to be as modular as you can by creating single-task functions, this will save you a lot of time. + +> There is many ways to run tasks in background and to perform actions on a specific time, the implementation proposed in this exercise is good for learning but should not be your preferred choice for production environments. + +### References + +- [Error handling in Python](https://docs.python.org/3.10/tutorial/errors.html) +- [Spawn a subprocess in Python](https://docs.python.org/3.10/library/subprocess.html) \ No newline at end of file