SW-415: automatically create dbcredentials file with sane defaults when no credentials are found

LCS/PyCommon/dbcredentials.py

@@ -130,9 +130,14 @@ class Credentials:
     return options
 
 class DBCredentials:
-  NoSectionError = NoSectionError
-
   def __init__(self, filepatterns=None):
+    self.filepatterns = filepatterns if filepatterns else [
+      "{LOFARROOT}/etc/dbcredentials/*.ini",
+      "{HOME}/.lofar/dbcredentials/*.ini",
+    ]
+    self.read_config_from_files()
+
+  def read_config_from_files(self, filepatterns=None):
     """
       Read database credentials from all configuration files matched by any of the patterns.
 
@@ -154,13 +159,10 @@ class DBCredentials:
       These database credentials can subsequently be queried under their
       symbolic name ("OTDB" in the example).
     """
-    if filepatterns is None:
-      filepatterns = [
-        "{LOFARROOT}/etc/dbcredentials/*.ini",
-        "{HOME}/.lofar/dbcredentials/*.ini",
-        ]
+    if filepatterns is not None:
+      self.filepatterns = filepatterns
 
-    self.files = sum([findfiles(p) for p in filepatterns],[])
+    self.files = sum([findfiles(p) for p in self.filepatterns],[])
 
     # make sure the files are mode 600 to hide passwords
     for file in self.files:
@@ -175,6 +177,19 @@ class DBCredentials:
     self.config = SafeConfigParser()
     self.config.read(self.files)
 
+  def create_default_file(self, database):
+    """
+    creates a dbcredentials file with defaults in ~/.lofar/dbcredentials/<database>.ini
+    :param database: name of the database/file
+    """
+    new_path = os.path.join(user_info.pw_dir, '.lofar', 'dbcredentials', database+'.ini')
+    if not os.path.exists(os.path.dirname(new_path)):
+      os.makedirs(os.path.dirname(new_path))
+    with open(new_path, 'w') as new_file:
+      new_file.write("[database:%s]\nhost=localhost\nuser=%s\npassword=unknown\ntype=unknown\nport=0\ndatabase=%s"
+                     % (database,user_info.pw_name,database))
+    logger.info("created default dbcredentials file for database=%s at %s", database, new_path)
+
   def get(self, database):
     """
       Return credentials for a given database.
@@ -182,8 +197,15 @@ class DBCredentials:
     # create default credentials
     creds = Credentials()
 
+    try:
       # read configuration (can throw NoSectionError)
       d = dict(self.config.items(self._section(database)))
+    except NoSectionError:
+      # create defaults file, and reload
+      self.create_default_file(database)
+      self.read_config_from_files()
+      # re-read configuration now that we have created a new file with defaults
+      d = dict(self.config.items(self._section(database)))
 
     # save the full config to support custom fields
     creds.config = d
@@ -202,6 +224,7 @@ class DBCredentials:
     return creds
 
 
+
   def set(self, database, credentials):
     """
       Add or overwrite credentials for a given database.