escale 0.6

Escale - Client-to-client synchronization based on external relay storage

Escale (French: stop, halt, stopover) synchronizes files between clients that operate behind restrictive firewalls.

It makes use of common file transfer solutions (FTP) and popular cloud solutions such as Dropbox, Google Drive and WebDAV servers including Yandex Disk.

Escale maintains a relay repository in a folder inside the remote or cloud storage space and frees memory as soon as copies of the shared files have been propagated to all the clients. File modifications are also propagated.

It features end-to-end encryption, quota management, filename filters, access control and adaptive transmission latencies.

It can run as a daemon and simultaneously synchronize several repositories between multiple clients.

License

Escale is governed by the CeCILL-C license.

It derivates from a work called Syncacre distributed under the terms of the ISC license. See release 0.4.3 for a copy of that former work.

Documentation

Please find the extended documentation at escale.readthedocs.io.

Changelog

• 0.6 (including 0.6-rc*):

  • new placeholder format with checksum support

  • checksum/hash algorithm configuration option

  • the checksum mechanism is active by default

  • parcimonious listing of relay repositories

  • easywebdav dependency removed

  • uncompleted transfer auto-fixing for shared and conservative synchronization mode (bug fix)

  • the configuration wizard offers a correct default passphrase filename (bug fix)

  • the configuration wizard understands ‘?’ and prints optional help messages

  • generic backend based on rclone; the protocol configuration option admits values rclone, dropbox, googlecloud, amazoncloud, s3 and onedrive

• 0.5 (including 0.5-rc*):

  • project name becomes Escale

  • license becomes CeCILL-C

  • license acceptance requested on the command-line

  • the syncacre script is renamed escale

  • escalectl script

  • access permissions (read, write, no read, no write) for individual files

  • mode configuration option

  • conservative synchronization mode

  • persistent data may be stored in the configuration directory

  • migration of relay repositories from a host to another

  • backup relay repositories to an archive

  • restore relay repositories from an archive

  • when missing, the client configuration option is set to the local hostname

  • unclaimed locks can be cleared by any client after lock timeout

  • lock timeout configuration option

  • puller count/pullers configuration option

  • if puller count is 1, regular files on the relay space are auto-deleted if the puller’s local copies are up-to-date

  • include/include files as synonyms for filter

  • exclude/exclude files configuration option

  • relay backend for directories in the local file system; the protocol configuration option admits value file

  • relay backend for Google Drive; the protocol configuration option admits value google and googledrive

  • the encryption configuration option admits value native for google/googledrive repositories

  • -q command-line option deprecated

  • python-daemon becomes a non-optional dependency

  • the documentation can be compiled by the Python2 version of Sphinx

  • documentation extensively redesigned

  • various bugfixes

• 0.4.3:

  • various bugfixes

  • syncacre script

• 0.4.2:

  • new lock format with version and access mode information

  • auto-repair for uncomplete transfers

  • pattern/filter configuration option to filter filenames by regular expression

  • -r command-line option for auto-restart when unrecoverable errors are hit

• 0.4.1:

  • ask for username and password at runtime

  • FTP backend now supports vsftpd and proftpd, MLSD-deficient FTP servers and FTP TLS connections

  • disk quota configuration option

  • certificate, certfile and keyfile configuration options

  • maintainer configuration option

  • email the maintainer when a client is aborting, if the local machine hosts an SMTP server

• 0.4:

  • FTP support (tested with pure-ftpd)

  • unicode support

  • -i command-line option that assists the user in configuring Syncacre

  • -p command-line option deprecated

  • if refresh configuration option is missing, defaults to True

  • most exceptions no longer make syncacre abort

  • temporary files are properly cleared

• 0.3.2:

  • file extension filter in configuration file

  • multiple backends for blowfish encryption; backend can be enforced with encryption = algorithm.backend where algorithm is blowfish here and backend can be either blowfish or cryptography

  • file names are correctly escaped

  • sleep times increase with successive sleeps

• 0.3.1:

  • push only and pull only configuration options introduced as replacements for read only and write only

  • ssl version and verify ssl configuration options

Roadmap

Coming features are:

• file auto-destruction when several pullers have been defined and one takes too much time to get its copy of the file

• more robust multi-puller logic

• split and recombine big files

• more (symmetric) cryptographic algorithms and more cryptographic options

• google-api-python-client backend for Google Drive

• F*EX/SEX backend?

• configuration wizard with explicit switch of commercial services