117 lines
3.3 KiB
Go
117 lines
3.3 KiB
Go
package fingerprint
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import (
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"fmt"
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"strconv"
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"time"
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consul "github.com/hashicorp/consul/api"
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log "github.com/hashicorp/go-hclog"
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)
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const (
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consulAvailable = "available"
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consulUnavailable = "unavailable"
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)
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// ConsulFingerprint is used to fingerprint for Consul
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type ConsulFingerprint struct {
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logger log.Logger
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client *consul.Client
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lastState string
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}
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// NewConsulFingerprint is used to create a Consul fingerprint
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func NewConsulFingerprint(logger log.Logger) Fingerprint {
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return &ConsulFingerprint{logger: logger.Named("consul"), lastState: consulUnavailable}
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}
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func (f *ConsulFingerprint) Fingerprint(req *FingerprintRequest, resp *FingerprintResponse) error {
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// Only create the client once to avoid creating too many connections to
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// Consul.
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if f.client == nil {
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consulConfig, err := req.Config.ConsulConfig.ApiConfig()
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if err != nil {
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return fmt.Errorf("Failed to initialize the Consul client config: %v", err)
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}
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f.client, err = consul.NewClient(consulConfig)
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if err != nil {
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return fmt.Errorf("Failed to initialize consul client: %s", err)
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}
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}
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// We'll try to detect consul by making a query to to the agent's self API.
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// If we can't hit this URL consul is probably not running on this machine.
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info, err := f.client.Agent().Self()
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if err != nil {
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f.clearConsulAttributes(resp)
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// Print a message indicating that the Consul Agent is not available
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// anymore
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if f.lastState == consulAvailable {
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f.logger.Info("consul agent is unavailable")
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}
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f.lastState = consulUnavailable
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return nil
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}
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if s, ok := info["Config"]["Server"].(bool); ok {
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resp.AddAttribute("consul.server", strconv.FormatBool(s))
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} else {
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f.logger.Warn("unable to fingerprint consul.server")
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}
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if v, ok := info["Config"]["Version"].(string); ok {
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resp.AddAttribute("consul.version", v)
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} else {
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f.logger.Warn("unable to fingerprint consul.version")
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}
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if r, ok := info["Config"]["Revision"].(string); ok {
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resp.AddAttribute("consul.revision", r)
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} else {
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f.logger.Warn("unable to fingerprint consul.revision")
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}
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if n, ok := info["Config"]["NodeName"].(string); ok {
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resp.AddAttribute("unique.consul.name", n)
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} else {
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f.logger.Warn("unable to fingerprint unique.consul.name")
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}
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if d, ok := info["Config"]["Datacenter"].(string); ok {
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resp.AddAttribute("consul.datacenter", d)
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} else {
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f.logger.Warn("unable to fingerprint consul.datacenter")
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}
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if dc, ok := resp.Attributes["consul.datacenter"]; ok {
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if name, ok2 := resp.Attributes["unique.consul.name"]; ok2 {
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resp.AddLink("consul", fmt.Sprintf("%s.%s", dc, name))
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}
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} else {
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f.logger.Warn("malformed Consul response prevented linking")
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}
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// If the Consul Agent was previously unavailable print a message to
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// indicate the Agent is available now
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if f.lastState == consulUnavailable {
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f.logger.Info("consul agent is available")
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}
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f.lastState = consulAvailable
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resp.Detected = true
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return nil
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}
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// clearConsulAttributes removes consul attributes and links from the passed
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// Node.
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func (f *ConsulFingerprint) clearConsulAttributes(r *FingerprintResponse) {
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r.RemoveAttribute("consul.server")
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r.RemoveAttribute("consul.version")
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r.RemoveAttribute("consul.revision")
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r.RemoveAttribute("unique.consul.name")
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r.RemoveAttribute("consul.datacenter")
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r.RemoveLink("consul")
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}
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func (f *ConsulFingerprint) Periodic() (bool, time.Duration) {
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return true, 15 * time.Second
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}
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