From 5b067a3e4fa2bee98096db0ba98155a585c2eb73 Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Thu, 5 Nov 2015 13:46:02 -0800
Subject: [PATCH 1/4] Merge fix

---
 client/driver/docker.go               |  4 +++-
 client/driver/exec.go                 |  4 +++-
 client/driver/java.go                 |  4 +++-
 client/driver/qemu.go                 |  4 +++-
 client/driver/raw_exec.go             |  4 +++-
 client/driver/rkt.go                  |  4 +++-
 client/fingerprint/arch.go            |  1 +
 client/fingerprint/consul.go          |  4 ++++
 client/fingerprint/cpu.go             |  1 +
 client/fingerprint/env_aws.go         |  1 +
 client/fingerprint/env_gce.go         |  1 +
 client/fingerprint/fingerprint.go     | 17 +++++++++++++++++
 client/fingerprint/host.go            |  1 +
 client/fingerprint/memory.go          |  1 +
 client/fingerprint/network_unix.go    |  1 +
 client/fingerprint/network_windows.go |  1 +
 client/fingerprint/storage.go         |  1 +
 17 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/client/driver/docker.go b/client/driver/docker.go
index d5031d5d97a..1708c692116 100644
--- a/client/driver/docker.go
+++ b/client/driver/docker.go
@@ -13,11 +13,13 @@ import (
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/driver/args"
+	"github.com/hashicorp/nomad/client/fingerprint"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
 type DockerDriver struct {
 	DriverContext
+	fingerprint.StaticFingerprinter
 }
 
 type dockerPID struct {
@@ -37,7 +39,7 @@ type dockerHandle struct {
 }
 
 func NewDockerDriver(ctx *DriverContext) Driver {
-	return &DockerDriver{*ctx}
+	return &DockerDriver{DriverContext: *ctx}
 }
 
 // dockerClient creates *docker.Client. In test / dev mode we can use ENV vars
diff --git a/client/driver/exec.go b/client/driver/exec.go
index 213bc574f51..4de719c465a 100644
--- a/client/driver/exec.go
+++ b/client/driver/exec.go
@@ -10,6 +10,7 @@ import (
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/driver/executor"
+	"github.com/hashicorp/nomad/client/fingerprint"
 	"github.com/hashicorp/nomad/client/getter"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
@@ -18,6 +19,7 @@ import (
 // features.
 type ExecDriver struct {
 	DriverContext
+	fingerprint.StaticFingerprinter
 }
 
 // execHandle is returned from Start/Open as a handle to the PID
@@ -29,7 +31,7 @@ type execHandle struct {
 
 // NewExecDriver is used to create a new exec driver
 func NewExecDriver(ctx *DriverContext) Driver {
-	return &ExecDriver{*ctx}
+	return &ExecDriver{DriverContext: *ctx}
 }
 
 func (d *ExecDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
diff --git a/client/driver/java.go b/client/driver/java.go
index 808bdfe5b90..1aa2c6d3f94 100644
--- a/client/driver/java.go
+++ b/client/driver/java.go
@@ -13,6 +13,7 @@ import (
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/driver/executor"
+	"github.com/hashicorp/nomad/client/fingerprint"
 	"github.com/hashicorp/nomad/client/getter"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
@@ -21,6 +22,7 @@ import (
 // It literally just fork/execs tasks with the java command.
 type JavaDriver struct {
 	DriverContext
+	fingerprint.StaticFingerprinter
 }
 
 // javaHandle is returned from Start/Open as a handle to the PID
@@ -32,7 +34,7 @@ type javaHandle struct {
 
 // NewJavaDriver is used to create a new exec driver
 func NewJavaDriver(ctx *DriverContext) Driver {
-	return &JavaDriver{*ctx}
+	return &JavaDriver{DriverContext: *ctx}
 }
 
 func (d *JavaDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
diff --git a/client/driver/qemu.go b/client/driver/qemu.go
index 0eab4e659ec..b0d0afc6294 100644
--- a/client/driver/qemu.go
+++ b/client/driver/qemu.go
@@ -16,6 +16,7 @@ import (
 
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
+	"github.com/hashicorp/nomad/client/fingerprint"
 	"github.com/hashicorp/nomad/client/getter"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
@@ -29,6 +30,7 @@ var (
 // planned in the future
 type QemuDriver struct {
 	DriverContext
+	fingerprint.StaticFingerprinter
 }
 
 // qemuHandle is returned from Start/Open as a handle to the PID
@@ -48,7 +50,7 @@ type qemuPID struct {
 
 // NewQemuDriver is used to create a new exec driver
 func NewQemuDriver(ctx *DriverContext) Driver {
-	return &QemuDriver{*ctx}
+	return &QemuDriver{DriverContext: *ctx}
 }
 
 func (d *QemuDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
diff --git a/client/driver/raw_exec.go b/client/driver/raw_exec.go
index 856f2b7fc65..c53e73a2b4f 100644
--- a/client/driver/raw_exec.go
+++ b/client/driver/raw_exec.go
@@ -13,6 +13,7 @@ import (
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/driver/args"
+	"github.com/hashicorp/nomad/client/fingerprint"
 	"github.com/hashicorp/nomad/client/getter"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
@@ -31,6 +32,7 @@ const (
 // and this should only be used when explicitly needed.
 type RawExecDriver struct {
 	DriverContext
+	fingerprint.StaticFingerprinter
 }
 
 // rawExecHandle is returned from Start/Open as a handle to the PID
@@ -42,7 +44,7 @@ type rawExecHandle struct {
 
 // NewRawExecDriver is used to create a new raw exec driver
 func NewRawExecDriver(ctx *DriverContext) Driver {
-	return &RawExecDriver{*ctx}
+	return &RawExecDriver{DriverContext: *ctx}
 }
 
 func (d *RawExecDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
diff --git a/client/driver/rkt.go b/client/driver/rkt.go
index 456e4e02bfe..3f191253174 100644
--- a/client/driver/rkt.go
+++ b/client/driver/rkt.go
@@ -17,6 +17,7 @@ import (
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/driver/args"
+	"github.com/hashicorp/nomad/client/fingerprint"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
@@ -30,6 +31,7 @@ var (
 // planned in the future
 type RktDriver struct {
 	DriverContext
+	fingerprint.StaticFingerprinter
 }
 
 // rktHandle is returned from Start/Open as a handle to the PID
@@ -50,7 +52,7 @@ type rktPID struct {
 
 // NewRktDriver is used to create a new exec driver
 func NewRktDriver(ctx *DriverContext) Driver {
-	return &RktDriver{*ctx}
+	return &RktDriver{DriverContext: *ctx}
 }
 
 func (d *RktDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
diff --git a/client/fingerprint/arch.go b/client/fingerprint/arch.go
index 869c542ebbb..16d8c99a878 100644
--- a/client/fingerprint/arch.go
+++ b/client/fingerprint/arch.go
@@ -10,6 +10,7 @@ import (
 
 // ArchFingerprint is used to fingerprint the architecture
 type ArchFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 
diff --git a/client/fingerprint/consul.go b/client/fingerprint/consul.go
index a03dfeec1fa..a8c054e21ab 100644
--- a/client/fingerprint/consul.go
+++ b/client/fingerprint/consul.go
@@ -63,3 +63,7 @@ func (f *ConsulFingerprint) Fingerprint(config *client.Config, node *structs.Nod
 
 	return true, nil
 }
+
+func (f *ConsulFingerprint) Periodic() (bool, time.Duration) {
+	return false, 15 * time.Second
+}
diff --git a/client/fingerprint/cpu.go b/client/fingerprint/cpu.go
index 3e809397e41..5027c8e9ae7 100644
--- a/client/fingerprint/cpu.go
+++ b/client/fingerprint/cpu.go
@@ -11,6 +11,7 @@ import (
 
 // CPUFingerprint is used to fingerprint the CPU
 type CPUFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 
diff --git a/client/fingerprint/env_aws.go b/client/fingerprint/env_aws.go
index 575409bf8ca..f5e26e7cbb6 100644
--- a/client/fingerprint/env_aws.go
+++ b/client/fingerprint/env_aws.go
@@ -69,6 +69,7 @@ var ec2InstanceSpeedMap = map[string]int{
 
 // EnvAWSFingerprint is used to fingerprint AWS metadata
 type EnvAWSFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 
diff --git a/client/fingerprint/env_gce.go b/client/fingerprint/env_gce.go
index f721fc36abd..faef7deabca 100644
--- a/client/fingerprint/env_gce.go
+++ b/client/fingerprint/env_gce.go
@@ -46,6 +46,7 @@ func lastToken(s string) string {
 
 // EnvGCEFingerprint is used to fingerprint GCE metadata
 type EnvGCEFingerprint struct {
+	StaticFingerprinter
 	client      *http.Client
 	logger      *log.Logger
 	metadataURL string
diff --git a/client/fingerprint/fingerprint.go b/client/fingerprint/fingerprint.go
index 4a42057b297..3154aad2bcf 100644
--- a/client/fingerprint/fingerprint.go
+++ b/client/fingerprint/fingerprint.go
@@ -3,11 +3,15 @@ package fingerprint
 import (
 	"fmt"
 	"log"
+	"time"
 
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
+// EmptyDuration is to be used by fingerprinters that are not periodic.
+const EmptyDuration = time.Duration(0)
+
 // BuiltinFingerprints is a slice containing the key names of all regestered
 // fingerprints available, to provided an ordered iteration
 var BuiltinFingerprints = []string{
@@ -59,4 +63,17 @@ type Fingerprint interface {
 	// Fingerprint is used to update properties of the Node,
 	// and returns if the fingerprint was applicable and a potential error.
 	Fingerprint(*config.Config, *structs.Node) (bool, error)
+
+	// Periodic is a mechanism for the fingerprinter to indicate that it should
+	// be run periodically. The return value is a boolean indicating if it
+	// should be periodic, and if true, a duration.
+	Periodic() (bool, time.Duration)
+}
+
+// StaticFingerprinter can be embeded in a struct that has a Fingerprint method
+// to make it non-periodic.
+type StaticFingerprinter struct{}
+
+func (s *StaticFingerprinter) Periodic() (bool, time.Duration) {
+	return false, EmptyDuration
 }
diff --git a/client/fingerprint/host.go b/client/fingerprint/host.go
index ac7a347f2ba..87acac63c97 100644
--- a/client/fingerprint/host.go
+++ b/client/fingerprint/host.go
@@ -14,6 +14,7 @@ import (
 
 // HostFingerprint is used to fingerprint the host
 type HostFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 
diff --git a/client/fingerprint/memory.go b/client/fingerprint/memory.go
index 5af097848c9..b249bebf575 100644
--- a/client/fingerprint/memory.go
+++ b/client/fingerprint/memory.go
@@ -11,6 +11,7 @@ import (
 
 // MemoryFingerprint is used to fingerprint the available memory on the node
 type MemoryFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 
diff --git a/client/fingerprint/network_unix.go b/client/fingerprint/network_unix.go
index 4278384e9a9..9adb5f41b0e 100644
--- a/client/fingerprint/network_unix.go
+++ b/client/fingerprint/network_unix.go
@@ -19,6 +19,7 @@ import (
 
 // NetworkFingerprint is used to fingerprint the Network capabilities of a node
 type NetworkFingerprint struct {
+	StaticFingerprinter
 	logger            *log.Logger
 	interfaceDetector NetworkInterfaceDetector
 }
diff --git a/client/fingerprint/network_windows.go b/client/fingerprint/network_windows.go
index 99467bcc8c9..b438b72920e 100644
--- a/client/fingerprint/network_windows.go
+++ b/client/fingerprint/network_windows.go
@@ -11,6 +11,7 @@ import (
 
 // NetworkFingerprint is used to fingerprint the Network capabilities of a node
 type NetworkFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 
diff --git a/client/fingerprint/storage.go b/client/fingerprint/storage.go
index 6abbe52e492..ead264845a8 100644
--- a/client/fingerprint/storage.go
+++ b/client/fingerprint/storage.go
@@ -18,6 +18,7 @@ import (
 // StorageFingerprint is used to measure the amount of storage free for
 // applications that the Nomad agent will run on this machine.
 type StorageFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 

From 8e0ab77b1042525cd231d729917da0442aaa2240 Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Thu, 5 Nov 2015 10:39:52 -0800
Subject: [PATCH 2/4] Add consul fingerprinter to builtin list; sort list; fix
 bad error in consul fingerprinter

---
 client/fingerprint/consul.go      |  2 +-
 client/fingerprint/fingerprint.go | 14 ++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/client/fingerprint/consul.go b/client/fingerprint/consul.go
index a8c054e21ab..01e3a658b60 100644
--- a/client/fingerprint/consul.go
+++ b/client/fingerprint/consul.go
@@ -48,7 +48,7 @@ func (f *ConsulFingerprint) Fingerprint(config *client.Config, node *structs.Nod
 	// If we can't hit this URL consul is probably not running on this machine.
 	info, err := consulClient.Agent().Self()
 	if err != nil {
-		return false, fmt.Errorf("Failed to query consul for agent status: %s", err)
+		return false, nil
 	}
 
 	node.Attributes["consul.server"] = strconv.FormatBool(info["Config"]["Server"].(bool))
diff --git a/client/fingerprint/fingerprint.go b/client/fingerprint/fingerprint.go
index 3154aad2bcf..a0139d485cb 100644
--- a/client/fingerprint/fingerprint.go
+++ b/client/fingerprint/fingerprint.go
@@ -16,26 +16,28 @@ const EmptyDuration = time.Duration(0)
 // fingerprints available, to provided an ordered iteration
 var BuiltinFingerprints = []string{
 	"arch",
+	"consul",
 	"cpu",
+	"env_aws",
+	"env_gce",
 	"host",
 	"memory",
-	"storage",
 	"network",
-	"env_aws",
-	"env_gce",
+	"storage",
 }
 
 // builtinFingerprintMap contains the built in registered fingerprints
 // which are available, corresponding to a key found in BuiltinFingerprints
 var builtinFingerprintMap = map[string]Factory{
 	"arch":    NewArchFingerprint,
+	"consul":  NewConsulFingerprint,
 	"cpu":     NewCPUFingerprint,
+	"env_aws": NewEnvAWSFingerprint,
+	"env_gce": NewEnvGCEFingerprint,
 	"host":    NewHostFingerprint,
 	"memory":  NewMemoryFingerprint,
-	"storage": NewStorageFingerprint,
 	"network": NewNetworkFingerprinter,
-	"env_aws": NewEnvAWSFingerprint,
-	"env_gce": NewEnvGCEFingerprint,
+	"storage": NewStorageFingerprint,
 }
 
 // NewFingerprint is used to instantiate and return a new fingerprint

From f43c067b3e62c98afeb7314302f1b3db03669db2 Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Thu, 5 Nov 2015 13:41:41 -0800
Subject: [PATCH 3/4] Client handles periodic fingerprinters

---
 client/client.go             | 24 ++++++++++++++++++++++++
 client/fingerprint/consul.go |  2 +-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/client/client.go b/client/client.go
index 744bad87691..2d466a7841b 100644
--- a/client/client.go
+++ b/client/client.go
@@ -443,11 +443,35 @@ func (c *Client) fingerprint() error {
 		if applies {
 			applied = append(applied, name)
 		}
+		p, period := f.Periodic()
+		if p {
+			// TODO: If more periodic fingerprinters are added, then
+			// fingerprintPeriodic should be used to handle all the periodic
+			// fingerprinters by using a priority queue.
+			go c.fingerprintPeriodic(name, f, period)
+		}
 	}
 	c.logger.Printf("[DEBUG] client: applied fingerprints %v", applied)
 	return nil
 }
 
+// fingerprintPeriodic runs a fingerprinter at the specified duration. If the
+// fingerprinter returns an error, the function exits.
+func (c *Client) fingerprintPeriodic(name string, f fingerprint.Fingerprint, d time.Duration) {
+	c.logger.Printf("[DEBUG] client: periodically fingerprinting %v at duration %v", name, d)
+	for {
+		select {
+		case <-time.After(d):
+			if _, err := f.Fingerprint(c.config, c.config.Node); err != nil {
+				c.logger.Printf("[DEBUG] client: disabling periodic fingerprinting for %v: %v", name, err)
+				return
+			}
+		case <-c.shutdownCh:
+			return
+		}
+	}
+}
+
 // setupDrivers is used to find the available drivers
 func (c *Client) setupDrivers() error {
 	var avail []string
diff --git a/client/fingerprint/consul.go b/client/fingerprint/consul.go
index 01e3a658b60..9ae81faf6a0 100644
--- a/client/fingerprint/consul.go
+++ b/client/fingerprint/consul.go
@@ -65,5 +65,5 @@ func (f *ConsulFingerprint) Fingerprint(config *client.Config, node *structs.Nod
 }
 
 func (f *ConsulFingerprint) Periodic() (bool, time.Duration) {
-	return false, 15 * time.Second
+	return true, 15 * time.Second
 }

From 10e19064d947c6cc2345821ec72ebbec6e989a22 Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Thu, 5 Nov 2015 18:47:16 -0800
Subject: [PATCH 4/4] Make periodic fingerprinting log the error

---
 client/client.go | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/client/client.go b/client/client.go
index 2d466a7841b..029ac395401 100644
--- a/client/client.go
+++ b/client/client.go
@@ -455,16 +455,14 @@ func (c *Client) fingerprint() error {
 	return nil
 }
 
-// fingerprintPeriodic runs a fingerprinter at the specified duration. If the
-// fingerprinter returns an error, the function exits.
+// fingerprintPeriodic runs a fingerprinter at the specified duration.
 func (c *Client) fingerprintPeriodic(name string, f fingerprint.Fingerprint, d time.Duration) {
 	c.logger.Printf("[DEBUG] client: periodically fingerprinting %v at duration %v", name, d)
 	for {
 		select {
 		case <-time.After(d):
 			if _, err := f.Fingerprint(c.config, c.config.Node); err != nil {
-				c.logger.Printf("[DEBUG] client: disabling periodic fingerprinting for %v: %v", name, err)
-				return
+				c.logger.Printf("[DEBUG] client: periodic fingerprinting for %v failed: %v", name, err)
 			}
 		case <-c.shutdownCh:
 			return