open-nomad/client/fingerprint/consul.go
Sean Chittenden e727fd8c3c
Centralize the creation of a consul/api.Config struct.
While documented, the consul.timeout parameter wasn't ever set
except one-off in the Consul fingerprinter.
2016-06-10 15:50:11 -04:00

101 lines
3 KiB
Go

package fingerprint
import (
"fmt"
"log"
"strconv"
"time"
consul "github.com/hashicorp/consul/api"
client "github.com/hashicorp/nomad/client/config"
"github.com/hashicorp/nomad/nomad/structs"
)
const (
consulAvailable = "available"
consulUnavailable = "unavailable"
)
// ConsulFingerprint is used to fingerprint the architecture
type ConsulFingerprint struct {
logger *log.Logger
client *consul.Client
lastState string
}
// NewConsulFingerprint is used to create an OS fingerprint
func NewConsulFingerprint(logger *log.Logger) Fingerprint {
return &ConsulFingerprint{logger: logger, lastState: consulUnavailable}
}
func (f *ConsulFingerprint) Fingerprint(config *client.Config, node *structs.Node) (bool, error) {
// Guard against uninitialized Links
if node.Links == nil {
node.Links = map[string]string{}
}
// Only create the client once to avoid creating too many connections to
// Consul.
if f.client == nil {
consulConfig, err := config.ConsulConfig.ApiConfig()
if err != nil {
return false, fmt.Errorf("Failed to initialize the Consul client config: %v", err)
}
f.client, err = consul.NewClient(consulConfig)
if err != nil {
return false, fmt.Errorf("Failed to initialize consul client: %s", err)
}
}
// We'll try to detect consul by making a query to to the agent's self API.
// If we can't hit this URL consul is probably not running on this machine.
info, err := f.client.Agent().Self()
if err != nil {
// Clear any attributes set by a previous fingerprint.
f.clearConsulAttributes(node)
// Print a message indicating that the Consul Agent is not available
// anymore
if f.lastState == consulAvailable {
f.logger.Printf("[INFO] fingerprint.consul: consul agent is unavailable")
}
f.lastState = consulUnavailable
return false, nil
}
node.Attributes["consul.server"] = strconv.FormatBool(info["Config"]["Server"].(bool))
node.Attributes["consul.version"] = info["Config"]["Version"].(string)
node.Attributes["consul.revision"] = info["Config"]["Revision"].(string)
node.Attributes["unique.consul.name"] = info["Config"]["NodeName"].(string)
node.Attributes["consul.datacenter"] = info["Config"]["Datacenter"].(string)
node.Links["consul"] = fmt.Sprintf("%s.%s",
node.Attributes["consul.datacenter"],
node.Attributes["unique.consul.name"])
// If the Consul Agent was previously unavailable print a message to
// indicate the Agent is available now
if f.lastState == consulUnavailable {
f.logger.Printf("[INFO] fingerprint.consul: consul agent is available")
}
f.lastState = consulAvailable
return true, nil
}
// clearConsulAttributes removes consul attributes and links from the passed
// Node.
func (f *ConsulFingerprint) clearConsulAttributes(n *structs.Node) {
delete(n.Attributes, "consul.server")
delete(n.Attributes, "consul.version")
delete(n.Attributes, "consul.revision")
delete(n.Attributes, "unique.consul.name")
delete(n.Attributes, "consul.datacenter")
delete(n.Links, "consul")
}
func (f *ConsulFingerprint) Periodic() (bool, time.Duration) {
return true, 15 * time.Second
}