(cqlsh) tab completion for triggers

patch by Mikhail Stepura; reviewed by Tyler Hobbs for CASSANDRA-7824

CHANGES.txt

@@ -1,4 +1,5 @@
 2.1.1
+ * (cqlsh) tab-completion for triggers (CASSANDRA-7824)
  * (cqlsh): Support for query paging (CASSANDRA-7514)
  * (cqlsh): Show progress of COPY operations (CASSANDRA-7789)
  * Add syntax to remove multiple elements from a map (CASSANDRA-6599)

bin/cqlsh

@@ -711,6 +711,14 @@ class Shell(cmd.Cmd):
 
         return cql3handling.UserTypesMeta.from_layout(data)
 
+    def get_trigger_names(self, ksname=None):
+        if ksname is None:
+            ksname = self.current_keyspace
+
+        return [trigger.name
+                for table in self.get_keyspace_meta(ksname).tables.values()
+                for trigger in table.triggers.values()]
+
     def reset_statement(self):
         self.reset_prompt()
         self.statement.truncate(0)

doc/cql3/CQL.textile

@@ -540,6 +540,39 @@ The @DROP TYPE@ statement results in the immediate, irreversible removal of a ty
 
 If the type does not exist, an error will be returned unless @IF EXISTS@ is used, in which case the operation is a no-op.
 
+h3(#createTriggerStmt). CREATE TRIGGER
+
+__Syntax:__
+
+bc(syntax).. 
+<create-trigger-stmt> ::= CREATE TRIGGER ( IF NOT EXISTS )? ( <triggername> )?
+                            ON <tablename> 
+                            USING <string>
+
+p. 
+__Sample:__
+
+bc(sample). 
+CREATE TRIGGER myTrigger ON myTable USING 'org.apache.cassandra.triggers.InvertedIndex';
+
+The actual logic that makes up the trigger can be written in any Java (JVM) language and exists outside the database. You place the trigger code in a @lib/triggers@ subdirectory of the Cassandra installation directory, it loads during cluster startup, and exists on every node that participates in a cluster. The trigger defined on a table fires before a requested DML statement occurs, which ensures the atomicity of the transaction.
+
+h3(#dropTriggerStmt). DROP TRIGGER
+
+__Syntax:__
+
+bc(syntax).. 
+<drop-trigger-stmt> ::= DROP TRIGGER ( IF EXISTS )? ( <triggername> )?
+                            ON <tablename>
+
+p. 
+__Sample:__
+
+bc(sample). 
+DROP TRIGGER myTrigger ON myTable;
+
+@DROP TRIGGER@ statement removes the registration of a trigger created using @CREATE TRIGGER@.
+
 h2(#dataManipulation). Data Manipulation
 
 h3(#insertStmt). INSERT

pylib/cqlshlib/cql3handling.py

@@ -228,10 +228,12 @@ JUNK ::= /([ \t\r\f\v]+|(--|[/][/])[^\n\r]*([\n\r]|$)|[/][*].*?[*][/])/ ;
                           | <createColumnFamilyStatement>
                           | <createIndexStatement>
                           | <createUserTypeStatement>
+                          | <createTriggerStatement>
                           | <dropKeyspaceStatement>
                           | <dropColumnFamilyStatement>
                           | <dropIndexStatement>
                           | <dropUserTypeStatement>
+                          | <dropTriggerStatement>
                           | <alterTableStatement>
                           | <alterKeyspaceStatement>
                           | <alterUserTypeStatement>
@@ -1153,6 +1155,28 @@ def username_name_completer(ctxt, cass):
     session = cass.session
     return [maybe_quote(row.values()[0].replace("'", "''")) for row in session.execute("LIST USERS")]
 
+syntax_rules += r'''
+<createTriggerStatement> ::= "CREATE" "TRIGGER" ( "IF" "NOT" "EXISTS" )? <cident>
+                               "ON" cf=<columnFamilyName> "USING" class=<stringLiteral>
+                           ;
+
+<dropTriggerStatement> ::= "DROP" "TRIGGER" ( "IF" "EXISTS" )? triggername=<cident>
+                             "ON" cf=<columnFamilyName>
+                         ;
+'''
+explain_completion('createTriggerStatement', 'class', '\'fully qualified class name\'')
+
+def get_trigger_names(ctxt, cass):
+    ks = ctxt.get_binding('ksname', None)
+    if ks is not None:
+        ks = dequote_name(ks)
+    return cass.get_trigger_names(ks)
+
+@completer_for('dropTriggerStatement', 'triggername')
+def alter_type_field_completer(ctxt, cass):
+    names = get_trigger_names(ctxt, cass)
+    return map(maybe_escape_name, names)
+
 # END SYNTAX/COMPLETION RULE DEFINITIONS
 
 CqlRuleSet.append_rules(syntax_rules)