osm.update.is_outdated: add optional offset argument

Author: tierpod

README.md

@@ -97,14 +97,11 @@ Modules documentation
 =====================
 
 * [tile methods](doc/osm_tile.md)
-
 * [data methods](doc/osm_data.md)
-
 * [tirex methods](doc/osm_tirex.md)
-
 * [mod_tile+renderd methods](doc/osm_renderd.md)
-
 * [custom http backend methods](doc/osm_http.md)
+* [update methods](doc/osm_update.md)
 
 
 TODO

doc/osm_update.md

@@ -64,7 +64,7 @@ Returns list of all cached items.
 is_outdated
 -----------
 
-**syntax:** *is_outdated = osm_update.is_outdated(metafilename, map)*
+**syntax:** *is_outdated = osm_update.is_outdated(metafilename, map, offset)*
 
 Checks if metatile file is outdated.
 
@@ -75,6 +75,16 @@ as outdated and rerender it.
 Uses nginx shared dict to cache mtime of flagfilename per map name (does not need to read this file
 on every request).
 
+*Offset* is the optional argument (int, default value is 0). This value will be subtracted from
+FLAGFILE modification time. Can be useful if some metatiles must be updated with some delay:
+
+```lua
+-- update metatiles for 18 zoom 30 days after new database was imported
+if z == 18 then
+  local is_outdated = osm_update.is_outdated('/var/lib/mod_tile/mapname/16/0/0/0/0/0.meta', 'mapname', 30 * 24 * 60 * 60)
+end
+```
+
 get_last_update
 ---------------
 
@@ -85,14 +95,14 @@ Get last update time stored in nginx shared memory cache for given map.
 get_mtime
 ---------
 
-**syntax:** *mtime = data.get_mtime("/var/lib/mod_tile/planet-import-complete")*
+**syntax:** *mtime = osm_update.get_mtime(filepath)*
 
-Get modification time of file. If file does not exists, returns nil.
+Get modification time of file. If file does not exist, returns nil.
 
 is_file_newer
 -------------
 
-**syntax:** *is_outdated = data.is_file_newer("/var/lib/mod_tile/planet-import-complete", "/var/lib/mod_tile/map/1/1/1.png")*
+**syntax:** *is_newer = osm_update.is_file_newer(filepath1, filepath12)*
 
 Compare modification time of two files. Returns true if file1 newer than file2.
 

osm/update.lua

@@ -26,7 +26,7 @@ local shmem = ngx.shared.osm_last_update
 local UPDATE_KEY = 'enabled'
 
 local _M = {
-    _VERSION = '0.2',
+    _VERSION = '0.3',
     FLAGFILE = '/var/lib/mod_tile/planet-import-complete',
     EXPTIME = 3600, -- one hour
 }
@@ -39,10 +39,11 @@ function _M.get_state()
 end
 
 -- checks if metatile file is outdated
--- args: metafilename, map (string)
+-- args: metafilename, map (string),
+--       offset (int) [optional, default=0]: offset in seconds, subtracted from metafilename mtime
 -- returns: true if metafilename older than flagfilename.
 --
-function _M.is_outdated(metafilename, map)
+function _M.is_outdated(metafilename, map, offset)
     if shmem == nil then
         return false
     end
@@ -56,7 +57,7 @@ function _M.is_outdated(metafilename, map)
             return false
         end
 
-        -- store mtime of flaf file to shared memory cache with key = map, value = last_update
+        -- store mtime of flag file to shared memory cache with key = map, value = last_update
         -- and expiration time = exptime
         last_update = mtime
         local success = shmem:set(map, last_update, _M.EXPTIME)
@@ -73,7 +74,8 @@ function _M.is_outdated(metafilename, map)
         return true
     end
 
-    return last_update > mtime
+    local _offset = offset or 0
+    return (last_update - _offset) > mtime
 end
 
 -- get last update time for map from nginx shared cache