add consistent cron expression for updtated things

src/requirements.txt

@@ -10,6 +10,7 @@ PyYAML==6.0.2
 grafana-client>=3.6.0
 requests~=2.32.3
 python-crontab~=3.0.0
+croniter~=6.0.0
 pandas~=2.1.4
 saqc==2.6.0
 cryptography>=43.0.0

src/setup_crontab.py

@@ -36,8 +36,8 @@ class CreateThingInCrontabHandler(AbstractHandler):
             for job in crontab:
                 if self.job_belongs_to_thing(job, thing):
                     logger.info(f"Updating cronjob for thing {thing.name}")
-                    self.update_job(job, thing)
-                    journal.info(f"Updated cronjob", thing.uuid)
+                    info = self.update_job(job, thing)
+                    journal.info(f"Updated cronjob to sync {info}", thing.uuid)
                     return
             # if no job was found, create a new one
             job = crontab.new()
@@ -66,7 +66,7 @@ class CreateThingInCrontabHandler(AbstractHandler):
             job.set_comment(comment, pre_comment=True)
             job.setall(schedule)
             job.set_command(command)
-            info = f"sFTP {thing.ext_sftp.uri} @ {interval}s"
+            info = f"sFTP {thing.ext_sftp.uri} @ {interval}m and schedule {schedule}"
         if thing.ext_api is not None:
             interval = int(thing.ext_api.sync_interval)
             schedule = cls.get_schedule(interval)
@@ -77,11 +77,48 @@ class CreateThingInCrontabHandler(AbstractHandler):
             job.set_comment(comment, pre_comment=True)
             job.setall(schedule)
             job.set_command(command)
-            info = f"{thing.ext_api.api_type_name}-API @ {interval}s"
+            info = f"{thing.ext_api.api_type_name}-API @ {interval}m and schedule {schedule}"
         return info
 
-    # alias
-    update_job = make_job
+    @classmethod
+    def update_job(cls, job: CronItem, thing: Thing) -> str:
+        info = ""
+        comment = cls.mk_comment(thing)
+        uuid = thing.uuid
+        current_interval = cls.get_current_interval(job)
+        if thing.ext_sftp is not None:
+            new_interval = int(thing.ext_sftp.sync_interval)
+            script = "/scripts/sync_sftp.py"
+            keyfile = thing.ext_sftp.ssh_priv_key
+            command = f"{script} {uuid} {keyfile} > $STDOUT 2> $STDERR"
+            job.enable(enabled=thing.ext_sftp.enabled)
+            job.set_comment(comment, pre_comment=True)
+            # if the interval has changed we want to ensure consistent starting times with the previous one
+            if current_interval != new_interval:
+                schedule = cls.update_cron_expression(job, new_interval)
+            else:
+                schedule = str(job.slices)
+            job.setall(schedule)
+            job.set_command(command)
+            info = (
+                f"sFTP {thing.ext_sftp.uri} @ {new_interval}m and schedule {schedule}"
+            )
+        elif thing.ext_api is not None:
+            new_interval = int(thing.ext_api.sync_interval)
+            script = f"/scripts/sync_{thing.ext_api.api_type_name}_api.py"
+            target_uri = thing.database.url
+            command = f"""{script} {uuid} "{thing.ext_api.settings}" {target_uri} > $STDOUT 2> $STDERR"""
+            job.enable(enabled=thing.ext_api.enabled)
+            job.set_comment(comment, pre_comment=True)
+            # if the interval has changed we want to ensure consistent starting dates
+            if current_interval != new_interval:
+                schedule = cls.update_cron_expression(job, new_interval)
+            else:
+                schedule = str(job.slices)
+            job.setall(schedule)
+            job.set_command(command)
+            info = f"{thing.ext_api.api_type_name}-API @ {new_interval}m and schedule {schedule}"
+        return info
 
     @staticmethod
     def job_belongs_to_thing(job: CronItem, thing: Thing) -> bool:
@@ -110,6 +147,43 @@ class CreateThingInCrontabHandler(AbstractHandler):
             delay_wd = randint(0, min(interval // 1440 - 1, 6))
             return f"{delay_m} {delay_h} * * {delay_wd}-6/{interval//1440}"
 
+    @staticmethod
+    def get_current_interval(job: CronItem) -> int:
+        """Get interval in minutes from crontab.txt entry"""
+        schedule = job.schedule()
+        next_run = schedule.get_next()
+        prev_run = schedule.get_prev()
+        interval = next_run - prev_run
+        return int(interval.seconds / 60)
+
+    @staticmethod
+    def extract_base_minute(schedule: str) -> int:
+        """Extract the minute value from the cron expression. In the case
+        of multiple values, the first one is returned.
+        """
+        minute_part = schedule.split()[0]
+        if "," in minute_part:
+            return int(minute_part.split(",")[0])
+        elif minute_part.isdigit():
+            return int(minute_part)
+        return 0
+
+    @classmethod
+    def update_cron_expression(cls, job, new_interval: int) -> str:
+        """Update cron while keeping the same base minute for consistency."""
+        base_minute = cls.extract_base_minute(str(job.slices))
+        if new_interval < 60:
+            minutes = sorted(
+                (base_minute + i * new_interval) % 60 for i in range(60 // new_interval)
+            )
+            return f"{','.join(map(str, minutes))} * * * *"
+
+        elif new_interval < 1440:
+            return f"{base_minute} */{new_interval // 60} * * *"
+
+        else:
+            return f"{base_minute} 0 */{new_interval // 1440} * *"
+
 
 if __name__ == "__main__":
     setup_logging(get_envvar("LOG_LEVEL", "INFO"))

src/timeio/configdb.py

@@ -135,7 +135,7 @@ def fetch_extapi_type_id(conn: Connection, name: str) -> int:
         [name],
     ).fetchone()
     if r is None:
-        raise ValueError(f"No entry for mqtt_device_type {name!r}")
+        raise ValueError(f"No entry for ext_api_type {name!r}")
     return r[0]