From 359251744f8761e5430d97e2e200f030966a43e5 Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Thu, 12 Nov 2015 15:28:22 -0800
Subject: [PATCH] Add TaskState to alloc

---
 api/allocations.go       |  2 ++
 api/tasks.go             | 28 ++++++++++++++++++++
 nomad/structs/structs.go | 56 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)

diff --git a/api/allocations.go b/api/allocations.go
index 829c1030f..00ab6984d 100644
--- a/api/allocations.go
+++ b/api/allocations.go
@@ -52,6 +52,7 @@ type Allocation struct {
 	DesiredDescription string
 	ClientStatus       string
 	ClientDescription  string
+	TaskStates         map[string]*TaskState
 	CreateIndex        uint64
 	ModifyIndex        uint64
 }
@@ -83,6 +84,7 @@ type AllocationListStub struct {
 	DesiredDescription string
 	ClientStatus       string
 	ClientDescription  string
+	TaskStates         map[string]*TaskState
 	CreateIndex        uint64
 	ModifyIndex        uint64
 }
diff --git a/api/tasks.go b/api/tasks.go
index 2535d5ec5..5c6dd600b 100644
--- a/api/tasks.go
+++ b/api/tasks.go
@@ -110,3 +110,31 @@ func (t *Task) Constrain(c *Constraint) *Task {
 	t.Constraints = append(t.Constraints, c)
 	return t
 }
+
+// TaskState tracks the current state of a task and events that caused state
+// transistions.
+type TaskState struct {
+	State  string
+	Events []*TaskEvent
+}
+
+// TaskEventType is the set of events that effect the state of a task.
+type TaskEventType int
+
+const (
+	TaskDriverFailure TaskEventType = iota
+	TaskStarted
+	TaskTerminated
+	TaskKilled
+)
+
+// TaskEvent is an event that effects the state of a task and contains meta-data
+// appropriate to the events type.
+type TaskEvent struct {
+	Type        TaskEventType
+	Time        int64
+	DriverError error
+	ExitCode    int
+	Signal      int
+	Message     string
+}
diff --git a/nomad/structs/structs.go b/nomad/structs/structs.go
index ce5007ac5..a3d535e72 100644
--- a/nomad/structs/structs.go
+++ b/nomad/structs/structs.go
@@ -1053,6 +1053,57 @@ func (t *Task) GoString() string {
 	return fmt.Sprintf("*%#v", *t)
 }
 
+// Set of possible states for a task.
+const (
+	TaskStatePending = "pending" // The task is waiting to be run.
+	TaskStateRunning = "running" // The task is currently running.
+	TaskStateDead    = "dead"    // Terminal state of task.
+)
+
+// TaskState tracks the current state of a task and events that caused state
+// transistions.
+type TaskState struct {
+	// The current state of the task.
+	State string
+
+	// Series of task events that transistion the state of the task.
+	Events []*TaskEvent
+}
+
+// TaskEventType is the set of events that effect the state of a task.
+type TaskEventType int
+
+const (
+	// A Driver failure indicates that the task could not be started due to a
+	// failure in the driver.
+	TaskDriverFailure TaskEventType = iota
+
+	// Task Started signals that the task was started and its timestamp can be
+	// used to determine the running length of the task.
+	TaskStarted
+
+	// Task terminated indicates that the task was started and exited.
+	TaskTerminated
+
+	// Task Killed indicates a user has killed the task.
+	TaskKilled
+)
+
+// TaskEvent is an event that effects the state of a task and contains meta-data
+// appropriate to the events type.
+type TaskEvent struct {
+	Type TaskEventType
+	Time int64 // Unix Nanosecond timestamp
+
+	// Driver Failure fields.
+	DriverError error // A driver error occured while starting the task.
+
+	// Task Terminated Fields.
+	ExitCode int    // The exit code of the task.
+	Signal   int    // The signal that terminated the task.
+	Message  string // A possible message explaining the termination of the task.
+}
+
 // Validate is used to sanity check a task group
 func (t *Task) Validate() error {
 	var mErr multierror.Error
@@ -1171,6 +1222,9 @@ type Allocation struct {
 	// ClientStatusDescription is meant to provide more human useful information
 	ClientDescription string
 
+	// TaskStates stores the state of each task,
+	TaskStates map[string]*TaskState
+
 	// Raft Indexes
 	CreateIndex uint64
 	ModifyIndex uint64
@@ -1200,6 +1254,7 @@ func (a *Allocation) Stub() *AllocListStub {
 		DesiredDescription: a.DesiredDescription,
 		ClientStatus:       a.ClientStatus,
 		ClientDescription:  a.ClientDescription,
+		TaskStates:         a.TaskStates,
 		CreateIndex:        a.CreateIndex,
 		ModifyIndex:        a.ModifyIndex,
 	}
@@ -1217,6 +1272,7 @@ type AllocListStub struct {
 	DesiredDescription string
 	ClientStatus       string
 	ClientDescription  string
+	TaskStates         map[string]*TaskState
 	CreateIndex        uint64
 	ModifyIndex        uint64
 }