From a5c60eb556f36ffdbf33803eb1b33649bc60f5d6 Mon Sep 17 00:00:00 2001
From: Armon Dadgar <armon.dadgar@gmail.com>
Date: Thu, 8 May 2014 15:01:02 -0700
Subject: [PATCH] consul: Adding new session tables

---
 consul/state_store.go     | 74 +++++++++++++++++++++++++++++++++------
 consul/structs/structs.go |  8 +++++
 2 files changed, 71 insertions(+), 11 deletions(-)

diff --git a/consul/state_store.go b/consul/state_store.go
index a5e99162e..1020cb882 100644
--- a/consul/state_store.go
+++ b/consul/state_store.go
@@ -17,6 +17,8 @@ const (
 	dbServices               = "services"
 	dbChecks                 = "checks"
 	dbKVS                    = "kvs"
+	dbSessions               = "sessions"
+	dbSessionChecks          = "sessionChecks"
 	dbMaxMapSize32bit uint64 = 512 * 1024 * 1024       // 512MB maximum size
 	dbMaxMapSize64bit uint64 = 32 * 1024 * 1024 * 1024 // 32GB maximum size
 )
@@ -29,16 +31,18 @@ const (
 // implementation uses the Lightning Memory-Mapped Database (MDB).
 // This gives us Multi-Version Concurrency Control for "free"
 type StateStore struct {
-	logger       *log.Logger
-	path         string
-	env          *mdb.Env
-	nodeTable    *MDBTable
-	serviceTable *MDBTable
-	checkTable   *MDBTable
-	kvsTable     *MDBTable
-	tables       MDBTables
-	watch        map[*MDBTable]*NotifyGroup
-	queryTables  map[string]MDBTables
+	logger             *log.Logger
+	path               string
+	env                *mdb.Env
+	nodeTable          *MDBTable
+	serviceTable       *MDBTable
+	checkTable         *MDBTable
+	kvsTable           *MDBTable
+	sessionTable       *MDBTable
+	sessionChecksTable *MDBTable
+	tables             MDBTables
+	watch              map[*MDBTable]*NotifyGroup
+	queryTables        map[string]MDBTables
 }
 
 // StateSnapshot is used to provide a point-in-time snapshot
@@ -49,6 +53,15 @@ type StateSnapshot struct {
 	lastIndex uint64
 }
 
+// sessionCheck is used to create a many-to-one table such
+// that each check registered by a session can be mapped back
+// to the session row.
+type sessionCheck struct {
+	Node    string
+	CheckID string
+	Session string
+}
+
 // Close is used to abort the transaction and allow for cleanup
 func (s *StateSnapshot) Close() error {
 	s.tx.Abort()
@@ -219,8 +232,47 @@ func (s *StateStore) initialize() error {
 		},
 	}
 
+	s.sessionTable = &MDBTable{
+		Name: dbSessions,
+		Indexes: map[string]*MDBIndex{
+			"id": &MDBIndex{
+				Unique: true,
+				Fields: []string{"ID"},
+			},
+			"node": &MDBIndex{
+				AllowBlank: true,
+				Fields:     []string{"Node"},
+			},
+		},
+		Decoder: func(buf []byte) interface{} {
+			out := new(structs.Session)
+			if err := structs.Decode(buf, out); err != nil {
+				panic(err)
+			}
+			return out
+		},
+	}
+
+	s.sessionChecksTable = &MDBTable{
+		Name: dbSessionChecks,
+		Indexes: map[string]*MDBIndex{
+			"id": &MDBIndex{
+				Unique: true,
+				Fields: []string{"Node", "CheckID", "Session"},
+			},
+		},
+		Decoder: func(buf []byte) interface{} {
+			out := new(sessionCheck)
+			if err := structs.Decode(buf, out); err != nil {
+				panic(err)
+			}
+			return out
+		},
+	}
+
 	// Store the set of tables
-	s.tables = []*MDBTable{s.nodeTable, s.serviceTable, s.checkTable, s.kvsTable}
+	s.tables = []*MDBTable{s.nodeTable, s.serviceTable, s.checkTable,
+		s.kvsTable, s.sessionTable, s.sessionChecksTable}
 	for _, table := range s.tables {
 		table.Env = s.env
 		table.Encoder = encoder
diff --git a/consul/structs/structs.go b/consul/structs/structs.go
index 2a672565f..61e575a25 100644
--- a/consul/structs/structs.go
+++ b/consul/structs/structs.go
@@ -335,6 +335,14 @@ type IndexedKeyList struct {
 	QueryMeta
 }
 
+// Session is used to represent an open session in the KV store.
+// This issued to associate node checks with acquired locks.
+type Session struct {
+	ID     string
+	Node   string
+	Checks []string
+}
+
 // Decode is used to decode a MsgPack encoded object
 func Decode(buf []byte, out interface{}) error {
 	var handle codec.MsgpackHandle