open-nomad/client/fingerprint/consul.go

236 lines
6.6 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package fingerprint
import (
"fmt"
"strconv"
"strings"
"time"
consulapi "github.com/hashicorp/consul/api"
log "github.com/hashicorp/go-hclog"
"github.com/hashicorp/go-version"
agentconsul "github.com/hashicorp/nomad/command/agent/consul"
)
const (
consulAvailable = "available"
consulUnavailable = "unavailable"
)
var (
// consulGRPCPortChangeVersion is the Consul version which made a breaking
// change to the way gRPC API listeners are created. This means Nomad must
// perform different fingerprinting depending on which version of Consul it
// is communicating with.
consulGRPCPortChangeVersion = version.Must(version.NewVersion("1.14.0"))
)
// ConsulFingerprint is used to fingerprint for Consul
type ConsulFingerprint struct {
logger log.Logger
client *consulapi.Client
lastState string
extractors map[string]consulExtractor
}
// consulExtractor is used to parse out one attribute from consulInfo. Returns
// the value of the attribute, and whether the attribute exists.
type consulExtractor func(agentconsul.Self) (string, bool)
// NewConsulFingerprint is used to create a Consul fingerprint
func NewConsulFingerprint(logger log.Logger) Fingerprint {
return &ConsulFingerprint{
logger: logger.Named("consul"),
lastState: consulUnavailable,
}
}
func (f *ConsulFingerprint) Fingerprint(req *FingerprintRequest, resp *FingerprintResponse) error {
// establish consul client if necessary
if err := f.initialize(req); err != nil {
return err
}
// query consul for agent self api
info := f.query(resp)
if len(info) == 0 {
// unable to reach consul, nothing to do this time
return nil
}
// apply the extractor for each attribute
for attr, extractor := range f.extractors {
if s, ok := extractor(info); !ok {
f.logger.Warn("unable to fingerprint consul", "attribute", attr)
} else {
resp.AddAttribute(attr, s)
}
}
// create link for consul
f.link(resp)
// indicate Consul is now available
if f.lastState == consulUnavailable {
f.logger.Info("consul agent is available")
}
f.lastState = consulAvailable
resp.Detected = true
return nil
}
func (f *ConsulFingerprint) Periodic() (bool, time.Duration) {
return true, 15 * time.Second
}
func (f *ConsulFingerprint) initialize(req *FingerprintRequest) error {
// Only create the Consul client once to avoid creating many connections
if f.client == nil {
consulConfig, err := req.Config.ConsulConfig.ApiConfig()
if err != nil {
return fmt.Errorf("failed to initialize Consul client config: %v", err)
}
f.client, err = consulapi.NewClient(consulConfig)
if err != nil {
return fmt.Errorf("failed to initialize Consul client: %s", err)
}
f.extractors = map[string]consulExtractor{
"consul.server": f.server,
"consul.version": f.version,
"consul.sku": f.sku,
"consul.revision": f.revision,
"unique.consul.name": f.name,
"consul.datacenter": f.dc,
"consul.segment": f.segment,
"consul.connect": f.connect,
"consul.grpc": f.grpc(consulConfig.Scheme),
"consul.ft.namespaces": f.namespaces,
}
}
return nil
}
func (f *ConsulFingerprint) query(resp *FingerprintResponse) agentconsul.Self {
// 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 {
// indicate consul no longer available
if f.lastState == consulAvailable {
f.logger.Info("consul agent is unavailable")
}
f.lastState = consulUnavailable
return nil
}
return info
}
func (f *ConsulFingerprint) link(resp *FingerprintResponse) {
if dc, ok := resp.Attributes["consul.datacenter"]; ok {
if name, ok2 := resp.Attributes["unique.consul.name"]; ok2 {
resp.AddLink("consul", fmt.Sprintf("%s.%s", dc, name))
}
} else {
f.logger.Warn("malformed Consul response prevented linking")
}
}
func (f *ConsulFingerprint) server(info agentconsul.Self) (string, bool) {
s, ok := info["Config"]["Server"].(bool)
return strconv.FormatBool(s), ok
}
func (f *ConsulFingerprint) version(info agentconsul.Self) (string, bool) {
v, ok := info["Config"]["Version"].(string)
return v, ok
}
func (f *ConsulFingerprint) sku(info agentconsul.Self) (string, bool) {
return agentconsul.SKU(info)
}
func (f *ConsulFingerprint) revision(info agentconsul.Self) (string, bool) {
r, ok := info["Config"]["Revision"].(string)
return r, ok
}
func (f *ConsulFingerprint) name(info agentconsul.Self) (string, bool) {
n, ok := info["Config"]["NodeName"].(string)
return n, ok
}
func (f *ConsulFingerprint) dc(info agentconsul.Self) (string, bool) {
d, ok := info["Config"]["Datacenter"].(string)
return d, ok
}
func (f *ConsulFingerprint) segment(info agentconsul.Self) (string, bool) {
tags, tagsOK := info["Member"]["Tags"].(map[string]interface{})
if !tagsOK {
return "", false
}
s, ok := tags["segment"].(string)
return s, ok
}
func (f *ConsulFingerprint) connect(info agentconsul.Self) (string, bool) {
c, ok := info["DebugConfig"]["ConnectEnabled"].(bool)
return strconv.FormatBool(c), ok
}
func (f *ConsulFingerprint) grpc(scheme string) func(info agentconsul.Self) (string, bool) {
return func(info agentconsul.Self) (string, bool) {
// The version is needed in order to understand which config object to
// query. This is because Consul 1.14.0 added a new gRPC port which
// broke the previous behaviour.
v, ok := info["Config"]["Version"].(string)
if !ok {
return "", false
}
consulVersion, err := version.NewVersion(v)
if err != nil {
return "", false
}
// If the Consul agent being fingerprinted is running a version less
// than 1.14.0 we use the original single gRPC port.
if consulVersion.Core().LessThan(consulGRPCPortChangeVersion.Core()) {
return f.grpcPort(info)
}
// Now that we know we are querying a Consul agent running v1.14.0 or
// greater, we need to select the correct port parameter from the
// config depending on whether we have been asked to speak TLS or not.
switch strings.ToLower(scheme) {
case "https":
return f.grpcTLSPort(info)
default:
return f.grpcPort(info)
}
}
}
func (f *ConsulFingerprint) grpcPort(info agentconsul.Self) (string, bool) {
p, ok := info["DebugConfig"]["GRPCPort"].(float64)
return fmt.Sprintf("%d", int(p)), ok
}
func (f *ConsulFingerprint) grpcTLSPort(info agentconsul.Self) (string, bool) {
p, ok := info["DebugConfig"]["GRPCTLSPort"].(float64)
return fmt.Sprintf("%d", int(p)), ok
}
func (f *ConsulFingerprint) namespaces(info agentconsul.Self) (string, bool) {
return strconv.FormatBool(agentconsul.Namespaces(info)), true
}