Add support for periodic fingerprints and make consul periodic

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

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

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) {

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) {

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) {

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) {

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) {

client/fingerprint/arch.go

@@ -10,6 +10,7 @@ import (
 
 // ArchFingerprint is used to fingerprint the architecture
 type ArchFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 

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))
@@ -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 true, 15 * time.Second
+}

client/fingerprint/cpu.go

@@ -11,6 +11,7 @@ import (
 
 // CPUFingerprint is used to fingerprint the CPU
 type CPUFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 

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
 }
 

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

client/fingerprint/fingerprint.go

@@ -3,35 +3,41 @@ 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{
 	"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
@@ -59,4 +65,17 @@ 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
 }

client/fingerprint/host.go

@@ -14,6 +14,7 @@ import (
 
 // HostFingerprint is used to fingerprint the host
 type HostFingerprint struct {
+	StaticFingerprinter
 	logger *log.Logger
 }
 

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
 }
 

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
 }

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
 }
 

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
 }