thegithubr / rsync_automator

A command line script that automatically generates rsync scripts and configures cron jobs based on a JSON config

Rsync Automator

A command line utility that can automatically

• Generate different rsync scripts for a list of tasks defined in a json config
• Generate crontab entries for the sync tasks
• Save the console output of scheduled rsync tasks to local log files
• Clean up old log files and only keep those from the latest N sync runs

Getting Started

Preparation

1. Make sure you have installed at least Python 3.9
2. Clone this repository
3. cd into the repository

Create a config file

The config file must be named as config.json and must be located in the repository root. It is highly recommended to copy example/full_config_example.json into config.json instead of creating it from scratch.

To copy the config file, simply run:

cp example/full_config_example.json config.json

A simplified config file may look like this:

{
  "rsync": "/usr/bin/rsync",
  "direction": "push",
  "source_root": "/home/myname",
  "dest_root": "myname@10.1.2.3:/path/to/dest/folder/10.1.2.3/home/myname",
  "ssh_port": 22,
  "log_dir_name": "__rsync_logs__",
  "max_log_files": 10,
  "generated_crontab_comment_mark": "[Backup my home folders]",
  "global_exclude": [
    ".DS_Store",
    "._*",
    "desktop.ini",
    "Thumbs.db"
  ],
  "global_args": [
    "--protect-args",
    "-avi"
  ],
  "tasks": [
    {
      "name": "My Awesome Project",
      "source_path": "/Documents/My Awesome Project/",
      "dest_path": "/My Awesome Project/",
      "exclude": [
        "temp/",
        "output/"
      ],
      "args": [
        "--chmod=777"
      ],
      "schedule": "0 0 * * *"
    },
    {
      "name": "Favorite Songs",
      "source_path": "/Music/Favorite/",
      "dest_path": "/My Favorite Songs/"
    }
  ]
}

As shown in the example above, this tool takes care of one-way syncing between one pair of source/destination devices, and multiple pairs of source/destination folders on them.

If you also need to sync folders to/from a different host, simply make another clone of this repository, and create another config there. You can have as many clones of this repository as you need on a single device. As long as you use a different generated_crontab_comment_mark for each project, there won't be any conflict or side effect.

More information about the config file can be found at the JSON Config Specs section below.

Run the script

./main.sh

Result of main.sh

Generated rsync scripts

All the generated rsync scripts are located in the output/ directory (relative to the repo's root directory), and they are ignored by Git.

Upon each run of the main.sh script, all previously generated files in the output/ directory are first deleted. Then, one individual bash script is generated for each task defined in tasks. The script names are in the format of rsync_{name}.sh, where {name} is the slugified task name.

Also, you can take a look at an example generated rsync script.

Generated "run all" script

A "run all" script is generated at output/run_all.sh. Running this script will execute all other generated rsync scripts (i.e. output/rsync_*.sh).

Configured cron jobs

If the schedule field is provided in a task, a cron job is automatically added to the current user's crontab. The automatically generated entries in crontab are commented with # {name} {generated_crontab_comment_mark}, where {name} is the task name, and {generated_crontab_comment_mark} is defined in the config file. Here is an example generated crontab entry.

Upon each run of main.sh, if there are existing crontab entries with exactly the same {generated_crontab_comment_mark}, they will be deleted first. Then, new entries created from the tasks in the current config file will be added to the bottom of crontab. Hence, it's highly recommended to use different {generated_crontab_comment_mark} values for different clones of this repository.

All other existing entries with other comments, or those without any comment, will be preserved as-is.

Right before main.sh completes and exits, it automatically calls crontab -l to print the crontab entries, so that you can visually verify whether the changes are correct.

[Optional] Use sudo to configure the root user's crontab

If the rsync tasks are expected to be run with sudo, maybe because the rsync sources or destinations are owned by root or other users, simply run sudo ./main.sh instead. Then, run sudo output/rsync_my-task.sh if needed.

Also, when the main.sh script is run with sudo, it will also add the cron jobs into the root user's crontab.

Logging

This feature can be turned on by providing the log_dir_name field in the config. If the value is not present, no log files will be saved.

With this feature on, when a generated rsync script (i.e. any of the output/rsync_*.sh) is run, either manually or automatically by cron, a log file can be created inside the task's {local_dir}/{log_dir_name}/ directory.

The {local_dir} is the local (as opposed to "remote") location of either the source or destination directory of a task, depending on whether the direction is a push or pull. If the task is a push, the {local_dir} is absolute source directory. Otherwise, if it's a pull, then the {local_dir} is the absolute destination directory.

Because this log directory will be automatically excluded by rsync, it's highly recommended to use a unique name, such as __rysnc_logs__, so that rsync will not accidentally exclude any sub-folder that should be synced.

Each log file is named with the start time of the run, in the format of 2022-07-06 09-57-48.log.

Also, only max_log_files most recent log files will be kept. Older log files will be automatically removed each time a generated rsync script is run. If max_log_files is not defined but logging is enabled, the value will be set to 10 by default.

Each log file contains the following information:

• Start time
• SSH port
• Rsync source
• Rsync destination
• The complete console output of rsync
• List of older log files to remove
• End time

You can take a look at the example generated rsync script to see what exactly is saved into log files, and how older files are automatically removed at each run.

JSON Config Specs

The Config object

The Config object is the root object in config.json.

Field	Required?	Type	Explanation
rsync	Optional	String	The path to the rsync binary (e.g. /usr/bin/rsync or /usr/local/bin/rsync). If not set, the default value is just "rsync" without any absolute path.
direction	Required	String	Either "push" or "pull". If the source is on the local device and the destination is on a remote device, it's a "push". Otherwise, it's a "pull".
source_root	Required	String	An absolute path on the source device.
dest_root	Required	String	An absolute path on the destination device.
ssh_port	Optional	Integer	The SSH port of the remote device. Defining this field will add the -e "ssh -p {port_number}" argument to rsync. If the SSH port is 22, or if both the source and destination are local, you don't need to define this field.
log_dir_name	Optional	String	The name of sub-directory inside of each task's local directory where the log files will be saved to. If this field is not defined, no logging files will be saved when the generated rsync scripts are run.
max_log_files	Optional	Integer	The maximum number of historical log files to be kept. When this limit is reached, the oldest log file will be removed. The default value is 10, if this field is not present but logging is enabled.
generated_crontab_comment_mark	Optional	String	A tag used to distinguish which entries in the cron table were automatically generated by this script. Once defined, this value must not be changed later. Otherwise, previously configured crontab entries won't be automatically cleaned up anymore. If this value is not present, none of the tasks below may define a schedule.
global_exclude	Optional	String[]	A list of string patterns to exclude with rsync's --exclude argument. This list will be appended to the start of each individual task's exclude list.
global_args	Optional	String[]	A list of additional rsync arguments that will be included in each task.
tasks	Required	Task[]	An array of Tasks.

The Task object:

Field	Required?	Type	Explanation
name	Required	String	The name of the task. The name after being slugified is used in the filename of the generated script, and the original name is a part of the comment of the generated crontab entry.
source_path	Required	String	Relative path from the source_root to the directory to sync. source_root and source_path will be literally concatenated before passing to rsync, so make sure they do not have redundant leading/trailing slashes. Also, see the section below Source path with ending slash for more info.
dest_path	Required	String	Relative path from the dest_root to the directory to sync. The ending slash is optional.
exclude	Optional	String[]	A list of string patterns to exclude with rsync's --exclude argument.
args	Optional	String[]	A list of rsync args to be added to this task.
schedule	Optional	String	A valid cron job schedule string. If not present, the main.sh script will not configure any crontab entry for this task. If this value is present, the Config.generated_crontab_comment_mark field above must also be present.

Rsync Recommendations

Arguments

• --protect-args: if the directories contain spaces or any other character that needs to be escaped, you must add this argument.
• A few arguments to help preserve more info in the log files:
  • -i or --itemize-changes
  • --human-readable
  • --stats
  • --verbose
• --omit-dir-times can be pretty useful to avoid unnecessary transfers

Exclusions

This is a list of some basic OS files that should be generally excluded:

{
  "global_exclude": [
    ".DS_Store",
    "._*",
    "desktop.ini",
    "Thumbs.db",
    "@eaDir"
  ]
}

Source path ending with slash

Say if we want to sync the contents of these two directories:

# The source directory at one location
my_source_dir
├── a.txt
├── b.txt
├── c.txt
└── some_subfolder
    └── more_file.txt

# The destination directory at another location
my_dest_dir
├── a.txt
├── b.txt
├── c.txt
└── some_subfolder
    └── more_file.txt

When using rsync, the source path must have an ending slash (/), and the destination path does not necessarily end with slash. For example:

rsync -av /path/to/my_source_dir/ /path/to/my_dest_dir

However, if the source path does not end with a slash, my_source_dir will be placed inside of my_dest_dir. The sync result will look like this:

my_dest_dir
├── a.txt
├── b.txt
├── c.txt
├── my_source_dir
│   ├── a.txt
│   ├── b.txt
│   ├── c.txt
│   └── some_subfolder
│       └── more_file.txt
└── some_subfolder
    └── more_file.txt