[web] improvement -> suggestions are cached in disk for 24 hours

bauh/gems/web/suggestions.py

@@ -1,5 +1,6 @@
 import os
 import traceback
+from datetime import datetime, timedelta
 from logging import Logger
 from pathlib import Path
 
@@ -7,7 +8,7 @@ import requests
 import yaml
 
 from bauh.api.http import HttpClient
-from bauh.gems.web import URL_SUGGESTIONS, SUGGESTIONS_CACHE_FILE
+from bauh.gems.web import URL_SUGGESTIONS, SUGGESTIONS_CACHE_FILE, SUGGESTIONS_CACHE_TS_FILE
 from bauh.view.util.translation import I18n
 
 
@@ -18,6 +19,68 @@ class SuggestionsManager:
         self.logger = logger
         self.i18n = i18n
 
+    def should_download(self, web_config: dict) -> bool:
+        exp = web_config['suggestions']['cache_exp']
+        if web_config['suggestions']['cache_exp'] is None:
+            self.logger.info("No cache expiration defined for suggestions")
+            return True
+
+        try:
+            exp = int(exp)
+        except ValueError:
+            self.logger.error("Error while parsing the 'suggestions.cache_exp' ({}) settings property".format(exp))
+            return True
+
+        if exp <= 0:
+            self.logger.info("No cache expiration defined for suggestions ({})".format(exp))
+            return True
+
+        if not os.path.exists(SUGGESTIONS_CACHE_FILE):
+            self.logger.info("No suggestions cached file found '{}'".format(SUGGESTIONS_CACHE_FILE))
+            return True
+
+        if not os.path.exists(SUGGESTIONS_CACHE_TS_FILE):
+            self.logger.info("No suggestions cache file timestamp found '{}'".format(SUGGESTIONS_CACHE_TS_FILE))
+            return True
+
+        with open(SUGGESTIONS_CACHE_TS_FILE) as f:
+            timestamp_str = f.read()
+
+        try:
+            sugs_timestamp = datetime.fromtimestamp(float(timestamp_str))
+        except:
+            self.logger.error("Could not parse the cached suggestions file timestamp: {}".format(timestamp_str))
+            return True
+
+        expired = sugs_timestamp + timedelta(days=exp) <= datetime.utcnow()
+
+        if expired:
+            self.logger.info("Cached suggestions file has expired.")
+            return True
+        else:
+            self.logger.info("Cached suggestions file is up to date")
+            return False
+
+    def read_cached(self, check_file: bool = True) -> dict:
+        if check_file and not os.path.exists(SUGGESTIONS_CACHE_FILE):
+            self.logger.warning("Cached suggestions file does not exist ({})".format(SUGGESTIONS_CACHE_FILE))
+            return {}
+
+        self.logger.info("Reading cached suggestions file '{}'".format(SUGGESTIONS_CACHE_FILE))
+        with open(SUGGESTIONS_CACHE_FILE) as f:
+            sugs_str = f.read()
+
+        if not sugs_str:
+            self.logger.warning("Cached suggestions file '{}' is empty".format(SUGGESTIONS_CACHE_FILE))
+            return {}
+
+        try:
+            return yaml.safe_load(sugs_str)
+        except:
+            self.logger.error("An unexpected exception happened")
+            traceback.print_exc()
+            return {}
+
     def download(self) -> dict:
         self.logger.info("Reading suggestions from {}".format(URL_SUGGESTIONS))
         try:
@@ -35,7 +98,7 @@ class SuggestionsManager:
         self.logger.info("Finished")
         return suggestions
 
-    def save_to_disk(self, suggestions: dict):
+    def save_to_disk(self, suggestions: dict, timestamp: float):
         if not suggestions:
             return
 
@@ -51,9 +114,19 @@ class SuggestionsManager:
         try:
             with open(SUGGESTIONS_CACHE_FILE, 'w+') as f:
                 f.write(yaml.safe_dump(suggestions))
-
-            self.logger.info("{} suggestions successfully cached to file '{}'".format(len(suggestions), SUGGESTIONS_CACHE_FILE))
         except:
             self.logger.error("Could write to {}".format(SUGGESTIONS_CACHE_FILE))
             traceback.print_exc()
             return
+
+        self.logger.info("{} suggestions successfully cached to file '{}'".format(len(suggestions), SUGGESTIONS_CACHE_FILE))
+
+        try:
+            with open(SUGGESTIONS_CACHE_TS_FILE, 'w+') as f:
+                f.write(str(timestamp))
+        except:
+            self.logger.error("Could not write to {}".format(SUGGESTIONS_CACHE_TS_FILE))
+            traceback.print_exc()
+            return
+
+        self.logger.info("Suggestions cached file timestamp ({}) successfully saved at '{}'".format(timestamp, SUGGESTIONS_CACHE_TS_FILE))