Machine readable (json) output of --version

[buhtz]

Doing rsync --version displays on stdout

rsync  version 3.2.3  protocol version 31
Copyright (C) 1996-2020 by Andrew Tridgell, Wayne Davison, and others.
Web site: https://rsync.samba.org/
Capabilities:
    64-bit files, 64-bit inums, 64-bit timestamps, 64-bit long ints,
    socketpairs, hardlinks, hardlink-specials, symlinks, IPv6, atimes,
    batchfiles, inplace, append, ACLs, xattrs, optional protect-args, iconv,
    symtimes, prealloc, stop-at, no crtimes
Optimizations:
    SIMD, asm, openssl-crypto
Checksum list:
    xxh128 xxh3 xxh64 (xxhash) md5 md4 none
Compress list:
    zstd lz4 zlibx zlib none

This is human- but not machine-readable. Parsing this is possible but not elegant. Would be nice to have a --json to print out something like this

{
    "version": "3.2.3",
    "protocol": "31",
    "Capabilities": [
        " 64-bit files", "64-bit inums", "64-bit timestamps"
    ],
    "Compress list": [
        "zstd", "lz4", "zlibx", "zlib", "none"
    }
}

[WayneD]

Seems useful. I've done something quick in rsync patches to be refined for future inclusion.

[buhtz]

Great to hear. Can you please show me an example output of it?

Or do you have a nightly build or a rep I can build from without adding patch diff filesß

[WayneD]

$ ./rsync -VV

{
  "program": "rsync",
  "version": "3.2.6-10-gad53a9b5",
  "protocol": "31.0",
  "copyright": "(C) 1996-2022 by Andrew Tridgell, Wayne Davison, and others.",
  "url": "https://rsync.samba.org/",
  "capabilities": {
    "file_bits": 64, "inum_bits": 64, "timestamp_bits": 64,
    "long_int_bits": 64, "socketpairs": true, "symlinks": true,
    "symtimes": true, "hardlinks": true, "hardlink_specials": true,
    "hardlink_symlinks": true, "IPv6": true, "atimes": true,
    "batchfiles": true, "inplace": true, "append": true, "ACLs": true,
    "xattrs": true, "secluded_args": "optional", "iconv": true,
    "prealloc": true, "stop_at": true, "crtimes": false
  },
  "optimizations": {
    "SIMD_roll": true, "asm_roll": true, "openssl_crypto": true,
    "asm_MD5": false
  },
  "checksum_list": [
    "xxh128", "xxh3", "xxh64", "md5", "md4", "sha1", "sha256", "sha512", "none"
  ],
  "compress_list": [
    "zstd", "lz4", "zlibx", "zlib", "none"
  ],
  "daemon_auth_list": [
    "sha512", "sha256", "sha1", "md5", "md4"
  ],
  "license": "GPL3",
  "caveat": "rsync comes with ABSOLUTELY NO WARRANTY"
}

[buhtz]

Thank you so much.

[WayneD]

FYI, this will be in 3.2.7pre pretty soon, so it will be in the github builds and in the rsync binaries dirs soon.

[WayneD]

In the latest git, see the script support/json-rsync-version as a way to get the json data from older rsyncs. Only tested back through 3.0.6 at the moment.

[WayneD]

FYI, I changed capabilities & optimizations into dictionaries so that someone doesn't need to scan a list for "no crtimes" vs "crtimes". That's now "crtimes": true|false

[buhtz]

Just a sidenote:

Version 3.2.3 (Debian stable) still overs a -VV which return the same content as -V.
Version 3.1.3: does not offer a -VV

Makes a bit hard to detect the json-supporting version of rsync because I can not be sure that -VV gives me a json output. ;)

[WayneD]

The output is a lot longer when -VV is a syntax error (and is on stderr). If the output doesn't start with a { then it's not the json.

The python script is provided as a way to get the json output no matter what the rsync version is. Install the script somewhere and run the equivalent of support/json-rsync-version /usr/bin/rsync (or pipe the --version --version output of an rsync into it) and you'll always get json (assuming that python3 is available on the host).

[buhtz]

The output is a lot longer when -VV is a syntax error (and is on stderr). If the output doesn't start with a { then it's not the json.

Yes I know. And I have to add checks for that in my code now. And I also found out that -V is not provided by 3.1.3
In the end the behaviour of -V , -VV is very different between the rsync versions.

What I know so far now

• rsync >= 3.2.6: -VV return a json
• rsync <= 3.2.5 and > (somewhere near) 3.1.3: -VV return the same as -V
• rsync <= (somewhere near) 3.1.3: -VV doesn't exists
• rsync == 3.1.3 (Ubuntu 20 LTS) doesn't even know '-V'

The python script is provided

But I won't ship my application with such a script but implement that in my own code.. At the end I have to parse the output. In my current code I try to extract the rsync version in different ways.

1. Use -VV and parse the output for an error message (-VV not exist)
   1. ...parse the output as json.
   2. ...parse the output via regex for the version string.
2. If -VV is unknown try a usual --version and parse the output via regex for a version string.

Please feel free to use my code in replacement of your script. See _get_extern_version() and that section in collect_diagnostics() calling that function twice.