simple-nixos-fediverse/garage.nix

let
  # generate one using openssl (somehow)
  # XXX: when importing, garage tells you importing is only meant for keys previously generated by garage. is it okay to generate them using openssl? it seems to work fine
  snakeoil_key = {
    id = "GK22a15201acacbd51cd43e327";
    secret = "82b2b4cbef27bf8917b350d5b10a87c92fa9c8b13a415aeeea49726cf335d74e";
  };
in
# TODO: expand to a multi-machine setup
{ config, lib, pkgs, ... }: {
  # add in options to ensure creation of buckets and keys
  options =
  let
    inherit (lib) types mkOption mkEnableOption;
  in {
    services.garage = {
      ensureBuckets = mkOption {
        type = types.attrsOf (types.submodule {
          options = {
            website = mkOption {
              type = types.bool;
              default = false;
            };
            # I think setting corsRules should allow another website to show images from your bucket
            corsRules = {
              enable = mkEnableOption "CORS Rules";
              allowedHeaders = mkOption {
                type = types.listOf types.str;
                default = [];
              };
              allowedMethods = mkOption {
                type = types.listOf types.str;
                default = [];
              };
              allowedOrigins = mkOption {
                type = types.listOf types.str;
                default = [];
              };
            };
            aliases = mkOption {
              type = types.listOf types.str;
              default = [];
            };
          };
        });
      };
      ensureKeys = mkOption {
        type = types.attrsOf (types.submodule {
          # TODO: these should be managed as secrets, not in the nix store
          options = {
            id = mkOption {
              type = types.str;
            };
            secret = mkOption {
              type = types.str;
            };
            # TODO: assert at least one of these is true
            #       currently, needs to be done in the top level module
            ensureAccess = mkOption {
              type = types.attrsOf (types.submodule {
                options = {
                  read = mkOption {
                    type = types.bool;
                    default = false;
                  };
                  write = mkOption {
                    type = types.bool;
                    default = false;
                  };
                  owner = mkOption {
                    type = types.bool;
                    default = false;
                  };
                };
              });
              default = [];
            };
          };
        });
      };
    };
  };

  config = {
    virtualisation.vmVariant = {
      virtualisation.diskSize = 2048;
      virtualisation.forwardPorts = [
        {
          from = "host";
          host.port = 3901;
          guest.port = 3901;
        }
        {
          from = "host";
          host.port = 3902;
          guest.port = 3902;
        }
      ];
    };

    environment.systemPackages = [ pkgs.minio-client pkgs.awscli ];

    networking.firewall.allowedTCPPorts = [ 3901 3902 ];
    services.garage = {
      enable = true;
      package = pkgs.garage_0_9;
      settings = {
        replication_mode = "none";
        # TODO: use a secret file
        #       I'd like to have a NixOS module that declares the need for a secret file
        #       that way, the need can be met by any secrets solution (agenix, sops-nix, colmena, a nixops4 module, ...)
        rpc_secret = "d576c4478cc7d0d94cfc127138cbb82018b0155c037d1c827dfb6c36be5f6625";
        # TODO: why does this have to be set? is there not a sensible default?
        rpc_bind_addr = "[::]:3901";
        rpc_public_addr = "[::1]:3901";
        s3_api.api_bind_addr = "[::]:3900";
        s3_web.bind_addr = "[::]:3902";
        s3_web.root_domain = ".web.garage.localhost";
        index = "index.html";

        s3_api.s3_region = "garage";
        s3_api.root_domain = ".s3.garage.localhost";
      };
    };
    systemd.services.ensure-garage = {
      after = [ "garage.service" ];
      wantedBy = [ "garage.service" ];
      path = [ config.services.garage.package pkgs.perl pkgs.awscli ];
      script = ''
        set -xeuo pipefail
        # give garage time to start up
        sleep 3

        # XXX: this is very sensitive to being a single instance
        # (doing the bare minimum to get garage up and running)
        # also, it's crazy that we have to parse command output like this
        # TODO: talk to garage maintainer about making this nicer to work with in Nix
        # before I do that though, I should figure out how setting it up across multiple machines will work
        # You could ask for a change or `--json` flag anyway, and maybe tell them what you're working on.
        GARAGE_ID=$(garage node id 2>/dev/null | perl -ne '/(.*)@.*/ && print $1')
        garage layout assign -z g1 -c 1G $GARAGE_ID
        LAYOUT_VER=$(garage layout show | perl -ne '/Current cluster layout version: (\d*)/ && print $1')
        garage layout apply --version $((LAYOUT_VER + 1))

        # XXX: this is a hack because we want to write to the buckets here but we're not guaranteed any access keys
        # TODO: generate this key here rather than using a well-known key
        garage key import --yes -n tmp ${snakeoil_key.id} ${snakeoil_key.secret}
        export AWS_ACCESS_KEY_ID=${snakeoil_key.id};
        export AWS_SECRET_ACCESS_KEY=${snakeoil_key.secret};

        ${
          lib.concatStringsSep "\n" (lib.mapAttrsToList (bucket: { website, aliases, corsRules }: ''
            # garage bucket info tells us if the bucket already exists
            garage bucket info ${bucket} || garage bucket create ${bucket}

            # TODO: should this --deny the website if `website` is false?
            ${lib.optionalString website ''
              garage bucket website --allow ${/* more robust: */ lib.strings.escapeShellArg bucket}
            ''}

            ${lib.concatStringsSep "\n" (map (alias: ''
              garage bucket alias ${bucket} ${alias}
            '') aliases)}

            ${lib.optionalString corsRules.enable ''
              # TODO: can i turn this whole thing into one builtins.toJSON?
              #       why not :D
              #       we also have `lib.strings.escapeShellArg` for the quoting
              export CORS=${lib.concatStrings [
                "'"
                ''{"CORSRules":[{''
                ''"AllowedHeaders":${builtins.toJSON corsRules.allowedHeaders},''
                ''"AllowedMethods":${builtins.toJSON corsRules.allowedMethods},''
                ''"AllowedOrigins":${builtins.toJSON corsRules.allowedOrigins}''
                ''}]}''
                "'"
              ]}

              garage bucket allow --read --write --owner ${bucket} --key tmp
              aws --endpoint http://s3.garage.localhost:3900 s3api put-bucket-cors --bucket ${bucket} --cors-configuration $CORS
              garage bucket deny --read --write --owner ${bucket} --key tmp
            ''}
          '') config.services.garage.ensureBuckets)
          # probably nice to factor this out into a function
        }
        ${
          lib.concatStringsSep "\n" (lib.mapAttrsToList (key: {id, secret, ensureAccess}: ''
            garage key import --yes -n ${key} ${id} ${secret}
            ${
              lib.concatStringsSep "\n" (lib.mapAttrsToList (bucket: { read, write, owner }: ''
                garage bucket allow ${lib.optionalString read "--read"} ${lib.optionalString write "--write"} ${lib.optionalString owner "--owner"} ${bucket} --key ${key}
              '') ensureAccess)
            }
          '') config.services.garage.ensureKeys)
        }

        garage key delete ${snakeoil_key.id} --yes
      '';
    };
  };
}