micro/server/options.go
Shulhan 1599d717af Add option to enable TCP check with Consul registry
One disadvantage of using TTL based health check is the high network
traffic between Consul agent (either between servers, or between server
and client).

In order for the services considered alive by Consul, microservices must
send an update TTL to Consul every n seconds (currently 30 seconds).

Here is the explanation about TTL check from Consul documentation [1]

    Time to Live (TTL) - These checks retain their last known state for a
    given TTL. The state of the check must be updated periodically over
    the HTTP interface. If an external system fails to update the status
    within a given TTL, the check is set to the failed state. This
    mechanism, conceptually similar to a dead man's switch, relies on the
    application to directly report its health. For example, a healthy app
    can periodically PUT a status update to the HTTP endpoint; if the app
    fails, the TTL will expire and the health check enters a critical
    state. The endpoints used to update health information for a given
    check are the pass endpoint and the fail endpoint. TTL checks also
    persist their last known status to disk. This allows the Consul agent
    to restore the last known status of the check across restarts.
    Persisted check status is valid through the end of the TTL from the
    time of the last check.


Hint:

    TTL checks also persist their last known status to disk. This allows
    the Consul agent to restore the last known status of the check
    across restarts.

When microservices update the TTL, Consul will write to disk. Writing to
disk means all other slaves need to replicate it, which means master need
to inform other standby Consul to pull the new catalog. Hence, the
increased traffic.

More information about this issue can be viewed at Consul mailing list [2].

[1] https://www.consul.io/docs/agent/checks.html
[2] https://groups.google.com/forum/#!topic/consul-tool/84h7qmCCpjg
2018-03-14 19:40:59 +07:00

209 lines
4.2 KiB
Go

package server
import (
"context"
"time"
"github.com/micro/go-micro/broker"
"github.com/micro/go-micro/codec"
"github.com/micro/go-micro/registry"
"github.com/micro/go-micro/server/debug"
"github.com/micro/go-micro/transport"
)
type Options struct {
Codecs map[string]codec.NewCodec
Broker broker.Broker
Registry registry.Registry
Transport transport.Transport
Metadata map[string]string
Name string
Address string
Advertise string
Id string
Version string
HdlrWrappers []HandlerWrapper
SubWrappers []SubscriberWrapper
RegisterTCPCheck bool
RegisterTTL time.Duration
RegisterInterval time.Duration
// Debug Handler which can be set by a user
DebugHandler debug.DebugHandler
// Other options for implementations of the interface
// can be stored in a context
Context context.Context
}
func newOptions(opt ...Option) Options {
opts := Options{
Codecs: make(map[string]codec.NewCodec),
Metadata: map[string]string{},
}
for _, o := range opt {
o(&opts)
}
if opts.Broker == nil {
opts.Broker = broker.DefaultBroker
}
if opts.Registry == nil {
opts.Registry = registry.DefaultRegistry
}
if opts.Transport == nil {
opts.Transport = transport.DefaultTransport
}
if opts.DebugHandler == nil {
opts.DebugHandler = debug.DefaultDebugHandler
}
if len(opts.Address) == 0 {
opts.Address = DefaultAddress
}
if len(opts.Name) == 0 {
opts.Name = DefaultName
}
if len(opts.Id) == 0 {
opts.Id = DefaultId
}
if len(opts.Version) == 0 {
opts.Version = DefaultVersion
}
return opts
}
// Server name
func Name(n string) Option {
return func(o *Options) {
o.Name = n
}
}
// Unique server id
func Id(id string) Option {
return func(o *Options) {
o.Id = id
}
}
// Version of the service
func Version(v string) Option {
return func(o *Options) {
o.Version = v
}
}
// Address to bind to - host:port
func Address(a string) Option {
return func(o *Options) {
o.Address = a
}
}
// The address to advertise for discovery - host:port
func Advertise(a string) Option {
return func(o *Options) {
o.Advertise = a
}
}
// Broker to use for pub/sub
func Broker(b broker.Broker) Option {
return func(o *Options) {
o.Broker = b
}
}
// Codec to use to encode/decode requests for a given content type
func Codec(contentType string, c codec.NewCodec) Option {
return func(o *Options) {
o.Codecs[contentType] = c
}
}
// Registry used for discovery
func Registry(r registry.Registry) Option {
return func(o *Options) {
o.Registry = r
}
}
// Transport mechanism for communication e.g http, rabbitmq, etc
func Transport(t transport.Transport) Option {
return func(o *Options) {
o.Transport = t
}
}
// DebugHandler for this server
func DebugHandler(d debug.DebugHandler) Option {
return func(o *Options) {
o.DebugHandler = d
}
}
// Metadata associated with the server
func Metadata(md map[string]string) Option {
return func(o *Options) {
o.Metadata = md
}
}
// Register the service with a TTL
func RegisterTTL(t time.Duration) Option {
return func(o *Options) {
o.RegisterTTL = t
}
}
//
// RegisterTCPCheck will tell the service provider to check the service address
// and port every `t` interval. It will enabled only if `t` is greater than 0.
// This option is for registry using Consul, see `TCP + Interval` more
// information [1].
//
// [1] https://www.consul.io/docs/agent/checks.html
//
func RegisterTCPCheck(t time.Duration) Option {
return func(o *Options) {
if t > time.Duration(0) {
o.RegisterTCPCheck = true
o.RegisterInterval = t
}
}
}
// Wait tells the server to wait for requests to finish before exiting
func Wait(b bool) Option {
return func(o *Options) {
if o.Context == nil {
o.Context = context.Background()
}
o.Context = context.WithValue(o.Context, "wait", b)
}
}
// Adds a handler Wrapper to a list of options passed into the server
func WrapHandler(w HandlerWrapper) Option {
return func(o *Options) {
o.HdlrWrappers = append(o.HdlrWrappers, w)
}
}
// Adds a subscriber Wrapper to a list of options passed into the server
func WrapSubscriber(w SubscriberWrapper) Option {
return func(o *Options) {
o.SubWrappers = append(o.SubWrappers, w)
}
}