diff options
Diffstat (limited to 'nixos/modules/services/backup/postgresql-wal-receiver.nix')
| -rw-r--r-- | nixos/modules/services/backup/postgresql-wal-receiver.nix | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/nixos/modules/services/backup/postgresql-wal-receiver.nix b/nixos/modules/services/backup/postgresql-wal-receiver.nix new file mode 100644 index 00000000000..32643adfdae --- /dev/null +++ b/nixos/modules/services/backup/postgresql-wal-receiver.nix @@ -0,0 +1,204 @@ +{ config, lib, pkgs, ... }: + +with lib; + +let + receiverSubmodule = { + options = { + postgresqlPackage = mkOption { + type = types.package; + example = literalExpression "pkgs.postgresql_11"; + description = '' + PostgreSQL package to use. + ''; + }; + + directory = mkOption { + type = types.path; + example = literalExpression "/mnt/pg_wal/main/"; + description = '' + Directory to write the output to. + ''; + }; + + statusInterval = mkOption { + type = types.int; + default = 10; + description = '' + Specifies the number of seconds between status packets sent back to the server. + This allows for easier monitoring of the progress from server. + A value of zero disables the periodic status updates completely, + although an update will still be sent when requested by the server, to avoid timeout disconnect. + ''; + }; + + slot = mkOption { + type = types.str; + default = ""; + example = "some_slot_name"; + description = '' + Require <command>pg_receivewal</command> to use an existing replication slot (see + <link xlink:href="https://www.postgresql.org/docs/current/warm-standby.html#STREAMING-REPLICATION-SLOTS">Section 26.2.6 of the PostgreSQL manual</link>). + When this option is used, <command>pg_receivewal</command> will report a flush position to the server, + indicating when each segment has been synchronized to disk so that the server can remove that segment if it is not otherwise needed. + + When the replication client of <command>pg_receivewal</command> is configured on the server as a synchronous standby, + then using a replication slot will report the flush position to the server, but only when a WAL file is closed. + Therefore, that configuration will cause transactions on the primary to wait for a long time and effectively not work satisfactorily. + The option <option>synchronous</option> must be specified in addition to make this work correctly. + ''; + }; + + synchronous = mkOption { + type = types.bool; + default = false; + description = '' + Flush the WAL data to disk immediately after it has been received. + Also send a status packet back to the server immediately after flushing, regardless of <option>statusInterval</option>. + + This option should be specified if the replication client of <command>pg_receivewal</command> is configured on the server as a synchronous standby, + to ensure that timely feedback is sent to the server. + ''; + }; + + compress = mkOption { + type = types.ints.between 0 9; + default = 0; + description = '' + Enables gzip compression of write-ahead logs, and specifies the compression level + (<literal>0</literal> through <literal>9</literal>, <literal>0</literal> being no compression and <literal>9</literal> being best compression). + The suffix <literal>.gz</literal> will automatically be added to all filenames. + + This option requires PostgreSQL >= 10. + ''; + }; + + connection = mkOption { + type = types.str; + example = "postgresql://user@somehost"; + description = '' + Specifies parameters used to connect to the server, as a connection string. + See <link xlink:href="https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING">Section 34.1.1 of the PostgreSQL manual</link> for more information. + + Because <command>pg_receivewal</command> doesn't connect to any particular database in the cluster, + database name in the connection string will be ignored. + ''; + }; + + extraArgs = mkOption { + type = with types; listOf str; + default = [ ]; + example = literalExpression '' + [ + "--no-sync" + ] + ''; + description = '' + A list of extra arguments to pass to the <command>pg_receivewal</command> command. + ''; + }; + + environment = mkOption { + type = with types; attrsOf str; + default = { }; + example = literalExpression '' + { + PGPASSFILE = "/private/passfile"; + PGSSLMODE = "require"; + } + ''; + description = '' + Environment variables passed to the service. + Usable parameters are listed in <link xlink:href="https://www.postgresql.org/docs/current/libpq-envars.html">Section 34.14 of the PostgreSQL manual</link>. + ''; + }; + }; + }; + +in { + options = { + services.postgresqlWalReceiver = { + receivers = mkOption { + type = with types; attrsOf (submodule receiverSubmodule); + default = { }; + example = literalExpression '' + { + main = { + postgresqlPackage = pkgs.postgresql_11; + directory = /mnt/pg_wal/main/; + slot = "main_wal_receiver"; + connection = "postgresql://user@somehost"; + }; + } + ''; + description = '' + PostgreSQL WAL receivers. + Stream write-ahead logs from a PostgreSQL server using <command>pg_receivewal</command> (formerly <command>pg_receivexlog</command>). + See <link xlink:href="https://www.postgresql.org/docs/current/app-pgreceivewal.html">the man page</link> for more information. + ''; + }; + }; + }; + + config = let + receivers = config.services.postgresqlWalReceiver.receivers; + in mkIf (receivers != { }) { + users = { + users.postgres = { + uid = config.ids.uids.postgres; + group = "postgres"; + description = "PostgreSQL server user"; + }; + + groups.postgres = { + gid = config.ids.gids.postgres; + }; + }; + + assertions = concatLists (attrsets.mapAttrsToList (name: config: [ + { + assertion = config.compress > 0 -> versionAtLeast config.postgresqlPackage.version "10"; + message = "Invalid configuration for WAL receiver \"${name}\": compress requires PostgreSQL version >= 10."; + } + ]) receivers); + + systemd.tmpfiles.rules = mapAttrsToList (name: config: '' + d ${escapeShellArg config.directory} 0750 postgres postgres - - + '') receivers; + + systemd.services = with attrsets; mapAttrs' (name: config: nameValuePair "postgresql-wal-receiver-${name}" { + description = "PostgreSQL WAL receiver (${name})"; + wantedBy = [ "multi-user.target" ]; + startLimitIntervalSec = 0; # retry forever, useful in case of network disruption + + serviceConfig = { + User = "postgres"; + Group = "postgres"; + KillSignal = "SIGINT"; + Restart = "always"; + RestartSec = 60; + }; + + inherit (config) environment; + + script = let + receiverCommand = postgresqlPackage: + if (versionAtLeast postgresqlPackage.version "10") + then "${postgresqlPackage}/bin/pg_receivewal" + else "${postgresqlPackage}/bin/pg_receivexlog"; + in '' + ${receiverCommand config.postgresqlPackage} \ + --no-password \ + --directory=${escapeShellArg config.directory} \ + --status-interval=${toString config.statusInterval} \ + --dbname=${escapeShellArg config.connection} \ + ${optionalString (config.compress > 0) "--compress=${toString config.compress}"} \ + ${optionalString (config.slot != "") "--slot=${escapeShellArg config.slot}"} \ + ${optionalString config.synchronous "--synchronous"} \ + ${concatStringsSep " " config.extraArgs} + ''; + }) receivers; + }; + + meta.maintainers = with maintainers; [ pacien ]; +} |