README
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Discov
Discov is a generic gRPC service registration and discovery / load balancing component.
Supported Scenarios
- The scenario of etcd as the service registry.
- The scenario of using headless service as DNS name to discover services in Kubernetes cluster.
- The scenario of DNS as a service registry.
Architecture
Examples
Documentation
License
Documentation
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Overview ¶
Package discov provides the APIs for service registration and discovery of gRPC.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Builder ¶
type Builder struct {
// contains filtered or unexported fields
}
Builder implements the gRPC resolver.Builder interface. It Builds a discov Resolver that implements the gRPC resolver.Resolver interface.
func NewBuilder ¶
func NewBuilder(opts ...BuilderOption) *Builder
NewBuilder returns a Builder that contain the passed options.
func (*Builder) Build ¶
func (b *Builder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (r resolver.Resolver, err error)
Build creates a new resolver for the given target.
If the authority of target that passed to grpc dial method is etcd, Build returns an internal etcdResolver, if the authority is dns, returns an internal dnsResolver.
The options passed to NewBuilder will be used in this method.
type BuilderOption ¶
type BuilderOption struct {
// contains filtered or unexported fields
}
BuilderOption is the option that passed to NewBuilder function.
func WithDNSPollingInterval ¶
func WithDNSPollingInterval(d time.Duration) BuilderOption
WithDNSPollingInterval customizes the polling frequency of the internal dnsResolver.
func WithEtcdClient ¶
func WithEtcdClient(cli *clientv3.Client) BuilderOption
WithEtcdClient injects an etcd client. The option is required when the authority of discov is etcd.
func WithEtcdKvResolver ¶
func WithEtcdKvResolver(r EtcdKvResolver) BuilderOption
WithEtcdKvResolver injects a custom EtcdKvResolver implementation to determine how the internal etcdResolver watches keys and retrieves addrs.
type DefaultEtcdKvBuilder ¶
type DefaultEtcdKvBuilder struct{}
DefaultEtcdKvBuilder will be used if the user does not RegisterKvBuilder.
func (*DefaultEtcdKvBuilder) BuildKey ¶
func (*DefaultEtcdKvBuilder) BuildKey(srvName, srvAddr string) string
BuildKey returns the key of "/srv/${srvName}/${srvAddr}".
func (*DefaultEtcdKvBuilder) BuildValue ¶
func (*DefaultEtcdKvBuilder) BuildValue(_, srvAddr string) string
BuildValue returns the value as the same as srvAddr.
type DefaultEtcdKvResolver ¶
type DefaultEtcdKvResolver struct{}
DefaultEtcdKvResolver will be used if the user doesn't set the EtcdKvResolver. DefaultEtcdKvResolver watches keys with prefix of "/srv/${srvName}", and treats the value of the key directly as an address.
func (*DefaultEtcdKvResolver) GetKeyPrefixForSrv ¶
func (*DefaultEtcdKvResolver) GetKeyPrefixForSrv(srvName string) string
GetKeyPrefixForSrv returns the prefix of "/srv/${srvName}".
func (*DefaultEtcdKvResolver) ResolveSrvAddr ¶
func (r *DefaultEtcdKvResolver) ResolveSrvAddr(value []byte) string
ResolveSrvAddr returns the string content of value.
type EtcdKvBuilder ¶
type EtcdKvBuilder interface {
// BuildKey builds the etcd key according to the name and
// the address of the service.
BuildKey(srvName, srvAddr string) (key string)
// BuildValue builds the etcd value according to the name
// and the address of the service.
BuildValue(srvName, srvAddr string) (value string)
}
EtcdKvBuilder builds the key and the value to store to etcd.
type EtcdKvResolver ¶
type EtcdKvResolver interface {
// GetKeyPrefixForSrv generates the key prefix for etcdResolver to watch.
// srvName is the endpoint in the target that passed to the grpc Dial method.
GetKeyPrefixForSrv(srvName string) (prefix string)
// ResolveSrvAddr resolves the service address from the value corresponding
// to the etcd key that be watched.
ResolveSrvAddr(value []byte) (srvAddr string)
}
EtcdKvResolver determines how the internal etcdResolver watches keys and retrieves addrs.
type EtcdSrvRecord ¶
type EtcdSrvRecord interface {
// Register registers the record to etcd.
// This method should be called when the service starts.
Register()
// Unregister unregisters the record from etcd.
// This method should be called when the service is closed.
Unregister(context.Context) error
// CatchRuntimeErrors catches runtime errors.
// Since the EtcdSrvRecord spawns goroutines to keep heartbeat
// to etcd after calling Register, some errors may occur at runtime.
CatchRuntimeErrors() <-chan error
// RegisterKvBuilder injects an EtcdKvBuilder to custom the
// format of key and value to store.
RegisterKvBuilder(EtcdKvBuilder)
}
EtcdSrvRecord is a service record to be registered to or unregistered from etcd.
func NewEtcdSrvRecord ¶
func NewEtcdSrvRecord(cli *clientv3.Client, srvName, srvAddr string) (EtcdSrvRecord, error)
NewEtcdSrvRecord creates a service record.
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