Merge branch 'L2SS-544-pythonise-archiver' into 'master'

L2SS-544: Improve LibConfiguration parsing, and return a dict instead of list...

Closes L2SS-544

See merge request !199

tangostationcontrol/tangostationcontrol/toolkit/archiver.py

@@ -2,7 +2,7 @@
 
 import logging
 
-from tango import DeviceProxy, AttributeProxy
+from tango import DeviceProxy, AttributeProxy, DevState, DevFailed
 
 import time
 import json, os
@@ -55,6 +55,27 @@ def split_tango_name(tango_fqname:str, tango_type:str):
     else:
         raise ValueError(f"Invalid value: {tango_type}. Please provide 'device' or 'attribute'.")
 
+ 
+def warn_if_attribute_not_found():
+    """
+      Log a warning if an exception is thrown indicating access to an non-existing attribute
+      was requested, and swallow the exception.
+    """
+    def inner(func):
+        @wraps(func)
+        def warn_wrapper(self, *args, **kwargs):
+            try:
+                return func(self, *args, **kwargs)
+            except DevFailed as e:
+                if e.args[0].reason == 'Attribute not found':
+                    logger.warning(f"Attribute {attribute_name} not found!")
+                else:
+                    raise
+
+        return warn_wrapper
+
+    return inner
+
 class Archiver():
     """
     The Archiver class implements the basic operations to perform attributes archiving
@@ -68,12 +89,11 @@ class Archiver():
         self.cm_name = cm_name
         self.cm = DeviceProxy(cm_name)
         try: 
-            cm_state = self.cm.state() # ping the device server
-            if 'FAULT' in str(cm_state):
-                raise Exception("Configuration Manager is in FAULT state")
+            if self.cm.state() == DevState.FAULT:
+                raise Exception(f"Configuration Manager {cm_name} is in FAULT state")
         except Exception as e:
-            raise Exception("Connection failed with Configuration Manager device") from e
-        self.es_list = [es_name for es_name in self.get_subscribers(from_db=False)] or []
+            raise Exception(f"Connection failed with Configuration Manager {cm_name}") from e
+        self.es_list = [es_name for es_name in self.get_subscribers(from_db=False)]
         self.cm.write_attribute('Context',context)    # Set default Context Archiving for all the subscribers
         self.selector = Selector() if selector_filename is None else Selector(selector_filename)  # Create selector for customized strategies
         try:
@@ -81,27 +101,25 @@ class Archiver():
         except Exception as e:
             raise Exception("Error in selecting configuration. Archiving framework will not be updated.") from e
     
-    def get_db_config(self, device_name:str):
+    def get_db_config(self, device_name:str) -> dict:
         """
         Retrieve the DB credentials from the Tango properties of Configuration Manager or EventSubscribers
         """
         device = DeviceProxy(device_name)
-        config_list = device.get_property('LibConfiguration')['LibConfiguration'] # dictionary {'LibConfiguration': list of strings}
-        host = str([s for s in config_list if "host" in s][0].split('=')[1])
-        libname = str([s for s in config_list if "libname" in s][0].split('=')[1])
-        dbname = str([s for s in config_list if "dbname" in s][0].split('=')[1])
-        port = str([s for s in config_list if "port" in s][0].split('=')[1])
-        user = str([s for s in config_list if "user" in s][0].split('=')[1])
-        pw = str([s for s in config_list if "password" in s][0].split('=')[1])
-        return [host,libname,dbname,port,user,pw]
+        # example LibConfiguration property value:
+        # ['connect_string= user=postgres password=password host=archiver-timescale port=5432 dbname=hdb', 'host=archiver-timescale', 'libname=libhdb++timescale.so', 'dbname=hdb', 'port=5432', 'user=postgres', 'password=password']
+        config_strs = device.get_property('LibConfiguration')['LibConfiguration']
+
+        config = dict(config_str.split("=",1) for config_str in config_strs)
+        return config
     
     def get_hdbpp_libname(self, device_name:str):
         """
         Get the hdbpp library name used by the Configuration Manager or by the EventSubscribers
         Useful in the case of different DBMS architectures (e.g. MySQL, TimescaleDB)
         """
-        config_list = self.get_db_config(device_name)
-        return config_list[1]
+        config = self.get_db_config(device_name)
+        return config["libname"]
     
     def get_subscribers(self, from_db:bool=False):
         """
@@ -186,15 +204,14 @@ class Archiver():
             es_name = last_es_name[:-2]+'0'+str(last_es_idx+1)   
         try: 
             es = DeviceProxy(es_name)
-            es_state = es.state() # ping the device server
-            if 'FAULT' in str(es_state):
-                raise Exception(f"{es_name} is in FAULT state")
+            if es.state() == DevState.FAULT:
+                raise Exception(f"Event Subscriber {es_name} is in FAULT state")
             self.cm.ArchiverAdd(device_name_url(es_name))
-        except Exception as e:
-            if 'already_present' in str(e):
-                logger.warning(f"Subscriber {es_name} already present in Configuration Manager")
+        except DevFailed as e:
+            if e.args[0].reason == "Archiver already present":
+                logger.warning(f"Event Subscriber {es_name} already present in Configuration Manager")
             else:
-                raise Exception from e
+                raise
 
     def add_attribute_to_archiver(self, attribute_name: str, polling_period: int, event_period: int, strategy: str = 'RUN', es_name:str=None):
         """
@@ -212,11 +229,11 @@ class Archiver():
             self.cm.write_attribute('SetPeriodEvent', event_period)
             self.cm.AttributeAdd()
             logger.info(f"Attribute {attribute_name} added to archiving list!")
-        except Exception as e:
-            if 'already archived' not in str(e).lower():
-                raise Exception from e
-            else:
+        except DevFailed as e:
+            if e.args[0].reason == 'Already archived':
                 logger.warning(f"Attribute {attribute_name} already in archiving list!")
+            else:
+                raise
 
     def add_attributes_by_device(self,device_name,global_archive_period:int = None, es_name:str=None, exclude:list = []):
         """
@@ -244,21 +261,17 @@ class Archiver():
                     raise Exception from e                        
             else:
                 logger.warning(f"Attribute {attr_fullname} will not be archived because polling is set to FALSE!")
-    
+
+    @warn_if_attribute_not_found() 
     def remove_attribute_from_archiver(self, attribute_name:str):
         """
         Stops the data archiving of the attribute passed as input, and remove it from the subscriber's list. 
         """
         attribute_name = attribute_name_from_url(attribute_name)
-        try:
-            self.cm.AttributeStop(attribute_name)
-            self.cm.AttributeRemove(attribute_name)
-            logger.warning(f"Attribute {attribute_name} removed!")
-        except Exception as e:
-            if 'attribute not found' not in str(e).lower():
-                raise Exception from e
-            else:
-                logger.warning(f"Attribute {attribute_name} not found in archiving list!")     
+
+        self.cm.AttributeStop(attribute_name)
+        self.cm.AttributeRemove(attribute_name)
+        logger.warning(f"Attribute {attribute_name} removed!")
     
     def remove_attributes_by_device(self,device_name:str,exclude:list=[]):
         """
@@ -293,33 +306,25 @@ class Archiver():
                 attr_fullname = attribute_name_from_url(a)
                 self.remove_attribute_from_archiver(attr_fullname)
 
+    @warn_if_attribute_not_found()
     def start_archiving_attribute(self, attribute_name:str):
         """
         Starts the archiving of the attribute passed as input.
         The attribute must be already present in the subscriber's list
         """
         attribute_name = attribute_name_from_url(attribute_name)
-        try:
-            self.cm.AttributeStart(attribute_name)
-        except Exception as e:
-            if 'attribute not found' not in str(e).lower():
-                raise Exception from e
-            else: 
-                logger.warning(f"Attribute {attribute_name} not found!")
+
+        self.cm.AttributeStart(attribute_name)
     
+    @warn_if_attribute_not_found()
     def stop_archiving_attribute(self, attribute_name:str):
         """
         Stops the archiving of the attribute passed as input.
         The attribute must be already present in the subscriber's list
         """
         attribute_name = attribute_name_from_url(attribute_name)
-        try:
-            self.cm.AttributeStop(attribute_name)
-        except Exception as e:
-            if 'attribute not found' not in str(e).lower():
-                raise Exception from e
-            else: 
-                logger.warning(f"Attribute {attribute_name} not found!")
+
+        self.cm.AttributeStop(attribute_name)
     
     def is_attribute_archived(self,attribute_name:str):
         """
@@ -369,15 +374,13 @@ class Archiver():
         """
         attrs = []
         errs = []
-        if es_name is not None:
-            es_list = [es_name]
-        else:
-            es_list = self.get_subscribers()
+        es_list = [es_name] if es_name else self.get_subscribers()
+
         for es_name in es_list:
             es = DeviceProxy(es_name)
             attrs.extend(list(es.AttributeList or []))
             errs.extend(list(es.AttributeErrorList or []))
-        return dict((a,e) for a,e in zip(attrs,errs) if e) or {}
+        return {a: e for a,e in zip(attrs,errs) if e}
    
     def get_attribute_errors(self,attribute_name:str):
         """
@@ -387,7 +390,7 @@ class Archiver():
         errs_dict = self.get_subscriber_errors()
         for e in errs_dict:
             if attribute_name in e:
-                return errs_dict.get(e)
+                return errs_dict[e]
         return None
     
     def get_subscriber_load(self,use_freq:bool=True,es_name:str = None):
@@ -395,10 +398,7 @@ class Archiver():
         Return the estimated load of an archiver, in frequency of records or number
         of attributes
         """
-        if es_name is not None:
-            es = DeviceProxy(es_name)
-        else: 
-            es = DeviceProxy(self.get_next_subscriber())
+        es = DeviceProxy(es_name or self.get_next_subscriber())
         if use_freq:
             return str(es.AttributeRecordFreq)+(' events/period' )
         else:
@@ -426,10 +426,10 @@ class Archiver():
         attribute_name = attribute_name_from_url(attribute_name)
         if self.is_attribute_archived(attribute_name):
             es = DeviceProxy(self.get_attribute_subscriber(attribute_name))
-            freq_dict = dict((a,r) for a,r in zip(es.AttributeList,es.AttributeRecordFreqList))
+            freq_dict = {a: r for a,r in zip(es.AttributeList,es.AttributeRecordFreqList)}
             for f in freq_dict:
                 if attribute_name.lower() in f:
-                    return freq_dict.get(f,0.)
+                    return freq_dict[f]
         else:
             logger.warning(f"Attribute {attribute_name} not found!")
     
@@ -440,10 +440,10 @@ class Archiver():
         attribute_name = attribute_name_from_url(attribute_name)
         if self.is_attribute_archived(attribute_name):
             es = DeviceProxy(self.get_attribute_subscriber(attribute_name))
-            fail_dict = dict((a,r) for a,r in zip(es.AttributeList,es.AttributeFailureFreqList))
+            fail_dict = {a: r for a,r in zip(es.AttributeList,es.AttributeFailureFreqList)}
             for f in fail_dict:
                 if attribute_name.lower() in f:
-                    return fail_dict.get(f,0.)
+                    return fail_dict[f]
         else:
             logger.warning(f"Attribute {attribute_name} not found!")