Commit 047fa8db authored by Doron Behar's avatar Doron Behar
Browse files

nixos/syncthing: Use API to merge / override configurations 

If one sets either of `override{Device,folder}s` to false, the jq `*`
operator doesn't merge well the devices and folders, creating duplicate
IDs for folders as observed in #230146. This PR makes the script iterate
via Nix / Bash loop the devices and folders IDs and merges the keys
using upstream's `curl -X POST` support for single objects.

Hence this commit fixes #230146.
parent 7b5e394e

nixos/modules/services/networking/syncthing.nix

+77 −17
Original line number Diff line number Diff line
@@ -29,11 +29,11 @@ let 
    folder.enable

  ) cfg.settings.folders);



  updateConfig = pkgs.writers.writeDash "merge-syncthing-config" ''

  jq = "${pkgs.jq}/bin/jq";

  updateConfig = pkgs.writers.writeBash "merge-syncthing-config" (''

    set -efu



    # be careful not to leak secrets in the filesystem or in process listings



    umask 0077



    # get the api key by parsing the config.xml
@@ -51,25 +51,85 @@ let 
            --retry 1000 --retry-delay 1 --retry-all-errors \

            "$@"

    }



    # query the old config

    old_cfg=$(curl ${cfg.guiAddress}/rest/config)



    # generate the new config by merging with the NixOS config options

    new_cfg=$(printf '%s\n' "$old_cfg" | ${pkgs.jq}/bin/jq -c ${escapeShellArg ''. * ${builtins.toJSON cleanedConfig} * {

        "devices": ('${escapeShellArg (builtins.toJSON devices)}'${optionalString (cfg.settings.devices == {} || ! cfg.overrideDevices) " + .devices"}),

        "folders": ('${escapeShellArg (builtins.toJSON folders)}'${optionalString (cfg.settings.folders == {} || ! cfg.overrideFolders) " + .folders"})

    }''})



    # send the new config

    curl -X PUT -d "$new_cfg" ${cfg.guiAddress}/rest/config



  '' +



  /* Syncthing's rest API for the folders and devices is almost identical.

  Hence we iterate them using lib.pipe and generate shell commands for both at

  the sime time. */

  (lib.pipe {

    # The attributes below are the only ones that are different for devices /

    # folders.

    devs = {

      new_conf_IDs = map (v: v.id) devices;

      GET_IdAttrName = "deviceID";

      override = cfg.overrideDevices;

      conf = devices;

      baseAddress = "${cfg.guiAddress}/rest/config/devices";

    };

    dirs = {

      new_conf_IDs = map (v: v.id) folders;

      GET_IdAttrName = "id";

      override = cfg.overrideFolders;

      conf = folders;

      baseAddress = "${cfg.guiAddress}/rest/config/folders";

    };

  } [

    # Now for each of these attributes, write the curl commands that are

    # identical to both folders and devices.

    (mapAttrs (conf_type: s:

      # We iterate the `conf` list now, and run a curl -X POST command for each, that

      # should update that device/folder only.

      lib.pipe s.conf [

        # Quoting https://docs.syncthing.net/rest/config.html:

        #

        # > PUT takes an array and POST a single object. In both cases if a

        # given folder/device already exists, it’s replaced, otherwise a new

        # one is added.

        #

        # What's not documented, is that using PUT will remove objects that

        # don't exist in the array given. That's why we use here `POST`, and

        # only if s.override == true then we DELETE the relevant folders

        # afterwards.

        (map (new_cfg: ''

          curl -d ${lib.escapeShellArg (builtins.toJSON new_cfg)} -X POST ${s.baseAddress}

        ''))

        (lib.concatStringsSep "\n")

      ]

      /* If we need to override devices/folders, we iterate all currently configured

      IDs, via another `curl -X GET`, and we delete all IDs that are not part of

      the Nix configured list of IDs

      */

      + lib.optionalString s.override ''

        old_conf_${conf_type}_ids="$(curl -X GET ${s.baseAddress} | ${jq} --raw-output '.[].${s.GET_IdAttrName}')"

        for id in ''${old_conf_${conf_type}_ids}; do

          if echo ${lib.concatStringsSep " " s.new_conf_IDs} | grep -q $id; then

            continue

          else

            curl -X DELETE ${s.baseAddress}/$id

          fi

        done

      ''

    ))

    builtins.attrValues

    (lib.concatStringsSep "\n")

  ]) +

  /* Now we update the other settings defined in cleanedConfig which are not

  "folders" or "devices". */

  (lib.pipe cleanedConfig [

    builtins.attrNames

    (lib.subtractLists ["folders" "devices"])

    (map (subOption: ''

      curl -X PUT -d ${lib.escapeShellArg (builtins.toJSON cleanedConfig.${subOption})} \

        ${cfg.guiAddress}/rest/config/${subOption}

    ''))

    (lib.concatStringsSep "\n")

  ]) + ''

    # restart Syncthing if required

    if curl ${cfg.guiAddress}/rest/config/restart-required |

       ${pkgs.jq}/bin/jq -e .requiresRestart > /dev/null; then

       ${jq} -e .requiresRestart > /dev/null; then

        curl -X POST ${cfg.guiAddress}/rest/system/restart

    fi

  '';

  '');

in {

  ###### interface

  options = {