dindexer

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What is dindexer?

Purpose

dindexer (from "Disc Indexer") is a program to help you keep track of where your files are as you back them up on external media. It's like updatedb/locate, but it's thought for never changing removable media, such as DVDs and BluRays.

Running dindexer on your disks will build a list of all your files and directories. You can associate those lists to a descriptive name and a number, so it's easy to find on what disk a file is on the next time you search for that file.

dindexer will also help you keeping track of duplicate data.

What dindexer is not?

To further clarify what dindexer's intended usage is, let's make a list of what it won't do for you:

• it's not a daemon - it's just a regular program that starts when you invoke it, performs its duties and then quits
• it's not a realtime file indexing utility; I believe there are a few indexing tools out there already, such as Baloo, mlocate and surely others, but dindexer doesn't duplicate any of those, nor wants to replace them
• it's not a backup tool; dindexer won't backup anything at all, won't make any copies of anything nor anything like that, so it's not like rsync; if you lose your DVD you previously scanned with dindexer, sorry but you've lost all of the data on your DVD

Usage example

You have a pile of DVDs, BluRays or any other external storage media on which you stored a copy of your files. Maybe you wanted to keep YouTube videos you don't want to have on your hard disk anymore, your pictures from your trip to Portugal a few years ago, your gpg private key backup and your Humble Bundle games. Maybe you're just moving away old stuff from your external hard disk onto DVDs, so you can store new data on your hard disk.

It's been a few years since you burned your first DVD, and your collection of backup has only grown more. You got to the point it's hard to tell what you have on your DVDs (especially those you just marked as "Backup March 2012"). Even worse, you don't know if those pictures from Portugal are already on some DVD - you think you backed them up somewhere, but just to be safe you burn them again on the next "Backup December 2015" DVD.

Five months later, you want to show your pictures of your trip to Portugal to your friend, but you finally deleted them from your hard disk. You probably have at least two copies on your DVDs, but where exactly? As you browse through your "pics backup"-labeled DVD and you realize it's a completely different sort of pictures you have on there, you think you should just give up on your Portugal photos for now.

dindexer aims to save you from that scenario. The intended usage flow is:

1. Prepare the list of files you want to burn in an external program like k3b for example, and make your backup
2. When finished, mount your new backup, for example on /media/cdrom
3. Scan your backup with dindexer using dindexer scan --setname "Disc 24 - pictures and stuff" /media/cdrom
4. When done, the list of all the files on your disc will be saved in dindexer's database
5. Make queries to find on which disc you stored your data - this part is still being worked on, but you can imagine something like dindexer query portugal.jpg returning "Disc 24 - pictures and stuff"
6. Go to where you dump - er... store your physical discs (the drawer in your desk, a box, the other room), find the disc you marked as "Disc 24", pop it in your cd-reader and voilà, here's where your portugal.jpg was!

WARNING: as dindexer is still being heavily developed, any of those steps can change in the future. I have a few ideas on how to make this program more convenient to use, but this will require some work. Contributions are welcome.

Configuration

As dindexer needs to write data to a PostgreSQL database, you need to configure access to it. Create a ~/.config/dindexer.yml file with the settings to connect to your database. For example:

%YAML 1.2
---
db_settings:
    username: bob_db
    password: my_secret_db_password
    dbname: dindexerdb
    port: 5432
    address: 127.0.0.1

Usage

Using dindexer is pretty straightforward: mount your DVD and scan it. For example:

mount /dev/cdrom /media/my_backup
dindexer scan --setname "My generic backup 2015-11-13" /media/my_backup

The program will go through every file in the path you specify. Hashing everything in that path could take a bit of time, so please be patient.

You can run dindexer --help to see a list of available switches.

Build instructions

Dependencies

The following libraries must be available on your system:

• PostgreSQL (libpq)
• Boost 1.53 or later
• yaml-cpp 0.5.1 or later
• libblkid (from util-linux/misc-utils) optional, build with -DDINDEXER_WITH_MEDIA_AUTODETECT=Off if you don't have this

Note: Although the CMakeLists.txt will say minimum required version for PostgreSQL is 8.3, this program has only ever been tested with 9.4. 8.3 is simply the threshold under which I'm sure the code will not work. If you want to try dindexer with a PostgreSQL version less than 9.4 you are welcome to do so, but please note I won't be able to make sure everything will work. Patches that address eventual issues are welcome.

Linux

mkdir dindexer_build
cd dindexer_build
cmake -DCMAKE_BUILD_TYPE=Release <path to dindexer source>
make -j2

Other platforms

I never tested dindexer on anything other than Linux. Note that the code assumes paths to be Unix-like. It also makes other assumptions about the current platform being Linux, so porting could be not so straightforward.

Project status

This project is at an early stage and is still being developed. Currently, only the indexer has been implemented. You can search the database manually if you know how to write the SQL queries you will need.

Useful technical details

Program overview

For the sake of clarity, from here on I will refer to the main program (more on it later) simply as "dindexer" and collectively call all the other executables "actions". I will refer to static and shared objects as "libraries". "dindexer" is also the name of this project as a whole; that meaning will be kept and it will hopefully be clear from the context.

dindexer is made of several actions and libraries. All of them are located in src/, but shared headers are found in include/. The main program, dindexer (the one users are supposed to run), is in src/main/ and it produces the dindexer executable. If you're working on this project, for your convenience you can symlink the dindexer executable into the root of your build directory. dindexer simply takes one action parameter and tries to match it to available actions. If successful it will run the relevant action passing all remaining command line parameters on.

Other than dindexer, in src/ you can find the following actions:

• delete
• locate
• query
• scan

and the following libraries:

• common a collection of common code useful for the CL fronted
• machinery the bulk of dindexer, such as the indexing functionality
• pq a c++ wrapper for libpq (PostgreSql)

Additionally inside include/helpers/ you will find header-only implementations of very generic helper tools.

Currently, actions are just the command line frontend to access the functionalities in the libraries. This way writing a new CLI or GUI should be relatively easy. This structure might change in the future.

Queries

Find duplicates

List all duplicate files belonging to different sets:

select files.hash, group_id, t.ct from files
inner join (
    select hash, count(*) as ct from files group by hash having count(distinct group_id) > 1
) t
on t.hash = files.hash
group by files.hash, group_id, t.ct order by files.hash;

Set number

In the sets table you can find a disk_number column that is currently not used. This is in case you have numbered discs, so you are free to put any number you like in that column.

Disc type

For your convenience, you can store the type of the disc you are going to index. Currently this has no impact on the program's behaviour. Available types are:

• C - CD-Rom
• D - Directory
• V - DVD
• B - BluRay
• F - Floppy Disk
• H - Hard Disk
• Z - Iomega Zip
• O - Other