From 941cd456ae1d0fd933a540468d2f9f13764d6de3 Mon Sep 17 00:00:00 2001
From: Aleksey Yeschenko <aleksey@apache.org>
Date: Wed, 23 Oct 2013 22:35:14 +0800
Subject: [PATCH] cqlsh: add SHOW SESSION <tracing-session> command

patch by Mikhail Stepura; reviewed by Aleksey Yeschenko for
CASSANDRA-6228
---
 CHANGES.txt                    |  1 +
 bin/cqlsh                      | 14 ++++++++++++--
 pylib/cqlshlib/cql3handling.py |  2 +-
 pylib/cqlshlib/tracing.py      |  8 +++++++-
 4 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 47e52f1709..9f7f3f0bac 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,6 +1,7 @@
 2.0.3
  * Reject bootstrapping if the node already exists in gossip (CASSANDRA-5571)
  * Fix NPE while loading paxos state (CASSANDRA-6211)
+ * cqlsh: add SHOW SESSION <tracing-session> command (CASSANDRA-6228)
 Merged from 1.2:
  * Fix altering column types (CASSANDRA-6185)
  * cqlsh: fix CREATE/ALTER WITH completion (CASSANDRA-6196)
diff --git a/bin/cqlsh b/bin/cqlsh
index 82c9906f76..33821118c8 100755
--- a/bin/cqlsh
+++ b/bin/cqlsh
@@ -32,7 +32,7 @@ exit 1
 from __future__ import with_statement
 
 description = "CQL Shell for Apache Cassandra"
-version = "4.0.2"
+version = "4.1.0"
 
 from StringIO import StringIO
 from itertools import groupby
@@ -245,7 +245,7 @@ cqlsh_extra_syntax_rules = r'''
                      | "EACH_QUORUM"
                      ;
 
-<showCommand> ::= "SHOW" what=( "VERSION" | "HOST" )
+<showCommand> ::= "SHOW" what=( "VERSION" | "HOST" | "SESSION" sessionid=<uuid> )
                 ;
 
 <sourceCommand> ::= "SOURCE" fname=<stringLiteral>
@@ -569,6 +569,9 @@ class Shell(cmd.Cmd):
         vers['cql'] = self.cql_version
         print "[cqlsh %(shver)s | Cassandra %(build)s | CQL spec %(cql)s | Thrift protocol %(thrift)s]" % vers
 
+    def show_session(self, sessionid):
+        print_trace_session(self, self.cursor, sessionid)
+
     def get_connection_versions(self):
         self.cursor.execute("select * from system.local where key = 'local'")
         result = self.fetchdict()
@@ -1554,6 +1557,10 @@ class Shell(cmd.Cmd):
         SHOW HOST
 
           Shows where cqlsh is currently connected.
+
+        SHOW SESSION <sessionid>
+
+          Pretty-prints the requested tracing session.
         """
         showwhat = parsed.get_binding('what').lower()
         if showwhat == 'version':
@@ -1561,6 +1568,9 @@ class Shell(cmd.Cmd):
             self.show_version()
         elif showwhat == 'host':
             self.show_host()
+        elif showwhat.startswith('session'):
+            session_id = parsed.get_binding('sessionid').lower()
+            self.show_session(session_id)
         else:
             self.printerr('Wait, how do I show %r?' % (showwhat,))
 
diff --git a/pylib/cqlshlib/cql3handling.py b/pylib/cqlshlib/cql3handling.py
index bc349a7644..e7aa9e122a 100644
--- a/pylib/cqlshlib/cql3handling.py
+++ b/pylib/cqlshlib/cql3handling.py
@@ -177,8 +177,8 @@ JUNK ::= /([ \t\r\f\v]+|(--|[/][/])[^\n\r]*([\n\r]|$)|[/][*].*?[*][/])/ ;
 <stringLiteral> ::= /'([^']|'')*'/ ;
 <quotedName> ::=    /"([^"]|"")*"/ ;
 <float> ::=         /-?[0-9]+\.[0-9]+/ ;
-<wholenumber> ::=   /[0-9]+/ ;
 <uuid> ::=          /[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/ ;
+<wholenumber> ::=   /[0-9]+/ ;
 <identifier> ::=    /[a-z][a-z0-9_]*/ ;
 <colon> ::=         ":" ;
 <star> ::=          "*" ;
diff --git a/pylib/cqlshlib/tracing.py b/pylib/cqlshlib/tracing.py
index fb8525d731..02d3296177 100644
--- a/pylib/cqlshlib/tracing.py
+++ b/pylib/cqlshlib/tracing.py
@@ -24,6 +24,9 @@ EVENTS_CF = 'events'
 
 def print_trace_session(shell, cursor, session_id):
     rows  = fetch_trace_session(cursor, session_id)
+    if not rows:
+        shell.printerr("Session %s wasn't found." % session_id)
+        return
     names = ['activity', 'timestamp', 'source', 'source_elapsed']
     types = [UTF8Type, UTF8Type, InetAddressType, Int32Type]
 
@@ -42,7 +45,10 @@ def fetch_trace_session(cursor, session_id):
                    "FROM %s.%s "
                    "WHERE session_id = %s" % (TRACING_KS, SESSIONS_CF, session_id),
                    consistency_level='ONE')
-    (request, coordinator, started_at, duration) = cursor.fetchone()
+    session = cursor.fetchone()
+    if not session:
+        return []
+    (request, coordinator, started_at, duration) = session
 
     cursor.execute("SELECT activity, event_id, source, source_elapsed "
                    "FROM %s.%s "