add beginnings of new scheduler model for recurring imports

archivebox/scheduler/models.py

@@ -0,0 +1,99 @@
+class ScheduledTask(models.Models):
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    
+    name = models.CharField(max_length=128, required=True, unique=True)
+    schedule = models.CharField(max_length=32, default='weekly')
+    enabled = models.BooleanField(default=True)
+
+    added = models.DateTimeField(auto_now_add=True)
+    updated = models.DateTimeField(auto_now=True)
+
+    runs = models.IntegerField(default=0, min_value=0, editable=False)
+    last_output = models.CharField(max_length=1024, default='')
+    last_start_ts = models.DateTimeField(default=None, null=True, blank=True)
+    last_end_ts = models.DateTimeField(default=None, null=True, blank=True)
+    
+    class Meta:
+        abstract = True
+
+
+class ScheduledAdd(ScheduledTask):
+    # main task parameters
+    urls = models.TextField(max_length=4096, default='', db_index=True)
+    tag = models.ManyToManyField(Tag)
+    
+    # add behavior flags
+    depth = models.IntegerField(min_value=0, max_value=1, default=0)
+    resnapshot = models.BooleanField(default=False)
+    overwrite = models.BooleanField(default=False)
+    index_only = models.BooleanField(default=False)
+    update_all = models.BooleanField(default=False)
+
+    extractors = models.CSVField(max_length=256, default='')
+    parser = models.CharField(max_length=32, default='auto', choices=PARSER_CHOICES)
+    
+    @cached_property
+    def source_filename(self) -> str:
+        return f'{self.short_id}-scheduled-import.txt'
+
+    def save(self, **kwargs):
+        self.urls_str = self.urls_str.strip()
+
+        assert self.urls_str or self.update_all, (
+            'you must either pass some urls to import, or set the task to update'
+            ' all existing URLS, otherwise it will do nothing')
+
+        assert self.schedule in ('hour', 'day', 'week', 'month', 'year') or isValidCronSchedule(self.schedule)
+
+        assert not (self.overwrite and self.resnapshot), (
+            'When snapshotting a URL thats previously snapshotted, '
+            'you may either overwrite it, or re-snapshot it, but not both')
+
+        # some more validation here...
+        save_text_as_source(self.urls, filename=self.source_filename)
+        self.schedule()
+
+    def schedule(self):
+        method = 'system crontab' if USE_SYSTEM_CRON else 'archivebox scheduler'
+        print(f'[*] Scheduling import {self.name} to run every {self.schedule} using {method}')
+
+        # TODO: decide whether to support system cron at all, or enforce python scheduler
+        if USE_SYSTEM_CRON:
+            schedule(
+                every=self.schedule,
+                depth=self.depth,
+                overwrite=self.overwrite,
+                import_path=self.urls_source_file_path,
+            )
+        else:
+            # TODO: update yacron/celery/huey/APScheduler etc. whatever scheduler we choose
+            pass
+
+    def run(self, force: bool=False):
+        if (not self.enabled) and (not force):
+            print(f'[!] Refusing to run scheduled import that is disabled: {self.name}')
+            return None
+
+        # TODO: enforce "at most once" or "at least once" concurrency somehow
+        
+        print(f'[+] [{timezone.now().isoformat()}] Running scheduled import {self.name}...\n')
+
+        self.last_start_ts = timezone.now()
+        self.runs += 1
+        try:
+            all_links, new_links = add(
+                urls=Path(self.urls_source_file_path),
+                tag=self.tag,
+                depth=self.depth,
+                update_all=self.update_all,
+                index_only=self.index_only,
+                overwrite=self.overwrite,
+                extractors=self.extractors,
+                parser=self.parser,
+            )
+            self.last_output = f'SUCCEEDED: {len(new_links)} new snapshots ({len(all_links)} total snapshots)'
+        except BaseException as err:
+            self.last_output = f'FAILED: {err.__class__.__name__} {err}'
+
+        self.last_end_ts = timezone.now()
+        self.save()