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[perso/Immae/Config/Nix.git] / modules / rsync_backup / default.nix
1 { lib, pkgs, config, ... }:
2 let
3 partModule = lib.types.submodule {
4 options = {
5 remote_folder = lib.mkOption {
6 type = lib.types.path;
7 description = ''
8 Path to backup
9 '';
10 };
11 exclude_from = lib.mkOption {
12 type = lib.types.listOf lib.types.path;
13 default = [];
14 description = ''
15 Paths to exclude from the backup
16 '';
17 };
18 files_from = lib.mkOption {
19 type = lib.types.listOf lib.types.path;
20 default = [];
21 description = ''
22 Paths to take for the backup
23 (if empty: whole folder minus exclude_from)
24 '';
25 };
26 args = lib.mkOption {
27 type = lib.types.nullOr lib.types.str;
28 default = null;
29 description = ''
30 additional arguments for rsync
31 '';
32 };
33 };
34 };
35 profileModule = lib.types.submodule {
36 options = {
37 keep = lib.mkOption {
38 type = lib.types.int;
39 default = 7;
40 description = ''
41 Number of backups to keep
42 '';
43 };
44 check_command = lib.mkOption {
45 type = lib.types.str;
46 default = "backup";
47 description = ''
48 command to check if backup needs to be done
49 '';
50 };
51 login = lib.mkOption {
52 type = lib.types.str;
53 description = ''
54 login to connect to
55 '';
56 };
57 host = lib.mkOption {
58 type = lib.types.str;
59 description = ''
60 host to connect to
61 '';
62 };
63 port = lib.mkOption {
64 type = lib.types.str;
65 default = "22";
66 description = ''
67 port to connect to
68 '';
69 };
70 host_key = lib.mkOption {
71 type = lib.types.str;
72 description = ''
73 Host key to use as known host
74 '';
75 };
76 host_key_type = lib.mkOption {
77 type = lib.types.str;
78 description = ''
79 Host key type
80 '';
81 };
82 parts = lib.mkOption {
83 type = lib.types.attrsOf partModule;
84 description = ''
85 folders to backup in the host
86 '';
87 };
88 };
89 };
90 cfg = config.services.rsyncBackup;
91
92 ssh_key = config.secrets.fullPaths."rsync_backup/identity";
93
94 backup_head = ''
95 #!${pkgs.stdenv.shell}
96 EXCL_FROM=`mktemp`
97 FILES_FROM=`mktemp`
98 TMP_STDERR=`mktemp`
99
100 on_exit() {
101 if [ -s "$TMP_STDERR" ]; then
102 cat "$TMP_STDERR"
103 fi
104 rm -f $TMP_STDERR $EXCL_FROM $FILES_FROM
105 }
106
107 trap "on_exit" EXIT
108
109 exec 2> "$TMP_STDERR"
110 exec < /dev/null
111
112 set -e
113 '';
114
115 backup_profile = name: profile: builtins.concatStringsSep "\n" (
116 [(backup_profile_head name profile)]
117 ++ lib.mapAttrsToList (backup_part name) profile.parts
118 ++ [(backup_profile_tail name profile)]);
119
120 backup_profile_head = name: profile: ''
121 ##### ${name} #####
122 PORT="${profile.port}"
123 DEST="${profile.login}@${profile.host}"
124 BASE="${cfg.mountpoint}/${name}"
125 OLD_BAK_BASE=$BASE/older/j
126 BAK_BASE=''${OLD_BAK_BASE}0
127 RSYNC_OUTPUT=$BASE/rsync_output
128 NBR=${builtins.toString profile.keep}
129
130 if ! ssh \
131 -o PreferredAuthentications=publickey \
132 -o StrictHostKeyChecking=yes \
133 -o ClearAllForwardings=yes \
134 -o UserKnownHostsFile=/dev/null \
135 -o CheckHostIP=no \
136 -p $PORT \
137 -i ${ssh_key} \
138 $DEST ${profile.check_command}; then
139 echo "Fichier de verrouillage backup sur $DEST ou impossible de se connecter" >&2
140 skip=$DEST
141 fi
142
143 rm -rf ''${OLD_BAK_BASE}''${NBR}
144 for j in `seq -w $(($NBR-1)) -1 0`; do
145 [ ! -d ''${OLD_BAK_BASE}$j ] && continue
146 mv ''${OLD_BAK_BASE}$j ''${OLD_BAK_BASE}$(($j+1))
147 done
148 mkdir $BAK_BASE
149 mv $RSYNC_OUTPUT $BAK_BASE
150 mkdir $RSYNC_OUTPUT
151
152 if [ "$skip" != "$DEST" ]; then
153 '';
154
155 backup_profile_tail = name: profile: ''
156 ssh -o UserKnownHostsFile=/dev/null -o CheckHostIP=no -i ${ssh_key} -p $PORT $DEST sh -c "date > .cache/last_backup"
157 fi # [ "$skip" != "$DEST" ]
158 ##### End ${name} #####
159 '';
160
161 backup_part = profile_name: part_name: part: ''
162 ### ${profile_name} ${part_name} ###
163 LOCAL="${part_name}"
164 REMOTE="${part.remote_folder}"
165
166 if [ ! -d "$BASE/$LOCAL" ]; then
167 mkdir $BASE/$LOCAL
168 fi
169 cd $BASE/$LOCAL
170 cat > $EXCL_FROM <<EOF
171 ${builtins.concatStringsSep "\n" part.exclude_from}
172 EOF
173 cat > $FILES_FROM <<EOF
174 ${builtins.concatStringsSep "\n" part.files_from}
175 EOF
176
177 OUT=$RSYNC_OUTPUT/$LOCAL
178 ${pkgs.rsync}/bin/rsync --new-compress -XAavbr --fake-super -e "ssh -o UserKnownHostsFile=/dev/null -o CheckHostIP=no -i ${ssh_key} -p $PORT" --numeric-ids --delete \
179 --backup-dir=$BAK_BASE/$LOCAL \${
180 lib.optionalString (part.args != null) "\n ${part.args} \\"}${
181 lib.optionalString (builtins.length part.exclude_from > 0) "\n --exclude-from=$EXCL_FROM \\"}${
182 lib.optionalString (builtins.length part.files_from > 0) "\n --files-from=$FILES_FROM \\"}
183 $DEST:$REMOTE . > $OUT || true
184 ### End ${profile_name} ${part_name} ###
185 '';
186 in
187 {
188 options.services.rsyncBackup = {
189 mountpoint = lib.mkOption {
190 type = lib.types.path;
191 description = "Path to the base folder for backups";
192 };
193 profiles = lib.mkOption {
194 type = lib.types.attrsOf profileModule;
195 default = {};
196 description = ''
197 Profiles to backup
198 '';
199 };
200 ssh_key_public = lib.mkOption {
201 type = lib.types.str;
202 description = "Public key for the backup";
203 };
204 ssh_key_private = lib.mkOption {
205 type = lib.types.str;
206 description = "Private key for the backup";
207 };
208 };
209
210 config = lib.mkIf (builtins.length (builtins.attrNames cfg.profiles) > 0) {
211 # FIXME: monitoring to check that backup is less than 14h old
212 users.users.backup = {
213 isSystemUser = true;
214 uid = config.ids.uids.backup;
215 group = "backup";
216 extraGroups = [ "keys" ];
217 };
218
219 users.groups.backup = {
220 gid = config.ids.gids.backup;
221 };
222
223 services.cron.systemCronJobs = let
224 backup = pkgs.writeScript "backup.sh" (builtins.concatStringsSep "\n" ([
225 backup_head
226 ] ++ lib.mapAttrsToList backup_profile cfg.profiles));
227 in [
228 ''
229 25 3,15 * * * backup ${backup}
230 ''
231 ];
232
233 programs.ssh.knownHosts = lib.attrsets.mapAttrs' (name: profile: lib.attrsets.nameValuePair name {
234 hostNames = [ profile.host ];
235 publicKey = "${profile.host_key_type} ${profile.host_key}";
236 }) cfg.profiles;
237
238 system.activationScripts.rsyncBackup = {
239 deps = [ "users" ];
240 text = builtins.concatStringsSep "\n" (map (v: ''
241 install -m 0700 -o backup -g backup -d ${cfg.mountpoint}/${v} ${cfg.mountpoint}/${v}/older ${cfg.mountpoint}/${v}/rsync_output
242 '') (builtins.attrNames cfg.profiles)
243 );
244 };
245
246 secrets.keys = [
247 {
248 dest = "rsync_backup/identity";
249 user = "backup";
250 group = "backup";
251 permissions = "0400";
252 text = cfg.ssh_key_private;
253 }
254 {
255 dest = "rsync_backup/identity.pub";
256 user = "backup";
257 group = "backup";
258 permissions = "0444";
259 text = cfg.ssh_key_public;
260 }
261 ];
262 };
263 }