consul/agent/structs/discovery_chain.go

263 lines
7.7 KiB
Go

package structs
import (
"encoding/json"
"fmt"
"time"
"github.com/hashicorp/consul/lib"
)
// CompiledDiscoveryChain is the result from taking a set of related config
// entries for a single service's discovery chain and restructuring them into a
// form that is more usable for actual service discovery.
type CompiledDiscoveryChain struct {
ServiceName string
Namespace string // the namespace that the chain was compiled within
Datacenter string // the datacenter that the chain was compiled within
// CustomizationHash is a unique hash of any data that affects the
// compilation of the discovery chain other than config entries or the
// name/namespace/datacenter evaluation criteria.
//
// If set, this value should be used to prefix/suffix any generated load
// balancer data plane objects to avoid sharing customized and
// non-customized versions.
CustomizationHash string `json:",omitempty"`
// Protocol is the overall protocol shared by everything in the chain.
Protocol string `json:",omitempty"`
// StartNode is the first key into the Nodes map that should be followed
// when walking the discovery chain.
StartNode string `json:",omitempty"`
// Nodes contains all nodes available for traversal in the chain keyed by a
// unique name. You can walk this by starting with StartNode.
//
// NOTE: The names should be treated as opaque values and are only
// guaranteed to be consistent within a single compilation.
Nodes map[string]*DiscoveryGraphNode `json:",omitempty"`
// Targets is a list of all targets used in this chain.
Targets map[string]*DiscoveryTarget `json:",omitempty"`
}
func (c *CompiledDiscoveryChain) WillFailoverThroughMeshGateway(node *DiscoveryGraphNode) bool {
if node.Type != DiscoveryGraphNodeTypeResolver {
return false
}
failover := node.Resolver.Failover
if failover != nil && len(failover.Targets) > 0 {
for _, failTargetID := range failover.Targets {
failTarget := c.Targets[failTargetID]
switch failTarget.MeshGateway.Mode {
case MeshGatewayModeLocal, MeshGatewayModeRemote:
return true
}
}
}
return false
}
// IsDefault returns true if the compiled chain represents no routing, no
// splitting, and only the default resolution. We have to be careful here to
// avoid returning "yep this is default" when the only resolver action being
// applied is redirection to another resolver that is default, so we double
// check the resolver matches the requested resolver.
func (c *CompiledDiscoveryChain) IsDefault() bool {
if c.StartNode == "" || len(c.Nodes) == 0 {
return true
}
node := c.Nodes[c.StartNode]
if node == nil {
panic("not possible: missing node named '" + c.StartNode + "' in chain '" + c.ServiceName + "'")
}
if node.Type != DiscoveryGraphNodeTypeResolver {
return false
}
if !node.Resolver.Default {
return false
}
target := c.Targets[node.Resolver.Target]
return target.Service == c.ServiceName && target.Namespace == c.Namespace
}
// ID returns an ID that encodes the service, namespace, and datacenter.
// This ID allows us to compare a discovery chain target to the chain upstream itself.
func (c *CompiledDiscoveryChain) ID() string {
return chainID("", c.ServiceName, c.Namespace, c.Datacenter)
}
func (c *CompiledDiscoveryChain) CompoundServiceName() ServiceName {
entMeta := NewEnterpriseMetaInDefaultPartition(c.Namespace)
return NewServiceName(c.ServiceName, &entMeta)
}
const (
DiscoveryGraphNodeTypeRouter = "router"
DiscoveryGraphNodeTypeSplitter = "splitter"
DiscoveryGraphNodeTypeResolver = "resolver"
)
// DiscoveryGraphNode is a single node in the compiled discovery chain.
type DiscoveryGraphNode struct {
Type string
Name string // this is NOT necessarily a service
// fields for Type==router
Routes []*DiscoveryRoute `json:",omitempty"`
// fields for Type==splitter
Splits []*DiscoverySplit `json:",omitempty"`
// fields for Type==resolver
Resolver *DiscoveryResolver `json:",omitempty"`
// shared by Type==resolver || Type==splitter
LoadBalancer *LoadBalancer `json:",omitempty"`
}
func (s *DiscoveryGraphNode) IsRouter() bool {
return s.Type == DiscoveryGraphNodeTypeRouter
}
func (s *DiscoveryGraphNode) IsSplitter() bool {
return s.Type == DiscoveryGraphNodeTypeSplitter
}
func (s *DiscoveryGraphNode) IsResolver() bool {
return s.Type == DiscoveryGraphNodeTypeResolver
}
func (s *DiscoveryGraphNode) MapKey() string {
return fmt.Sprintf("%s:%s", s.Type, s.Name)
}
// compiled form of ServiceResolverConfigEntry
type DiscoveryResolver struct {
Default bool `json:",omitempty"`
ConnectTimeout time.Duration `json:",omitempty"`
Target string `json:",omitempty"`
Failover *DiscoveryFailover `json:",omitempty"`
}
func (r *DiscoveryResolver) MarshalJSON() ([]byte, error) {
type Alias DiscoveryResolver
exported := &struct {
ConnectTimeout string `json:",omitempty"`
*Alias
}{
ConnectTimeout: r.ConnectTimeout.String(),
Alias: (*Alias)(r),
}
if r.ConnectTimeout == 0 {
exported.ConnectTimeout = ""
}
return json.Marshal(exported)
}
func (r *DiscoveryResolver) UnmarshalJSON(data []byte) error {
type Alias DiscoveryResolver
aux := &struct {
ConnectTimeout string
*Alias
}{
Alias: (*Alias)(r),
}
if err := lib.UnmarshalJSON(data, &aux); err != nil {
return err
}
var err error
if aux.ConnectTimeout != "" {
if r.ConnectTimeout, err = time.ParseDuration(aux.ConnectTimeout); err != nil {
return err
}
}
return nil
}
// compiled form of ServiceRoute
type DiscoveryRoute struct {
Definition *ServiceRoute `json:",omitempty"`
NextNode string `json:",omitempty"`
}
// compiled form of ServiceSplit
type DiscoverySplit struct {
Weight float32 `json:",omitempty"`
NextNode string `json:",omitempty"`
}
// compiled form of ServiceResolverFailover
type DiscoveryFailover struct {
Targets []string `json:",omitempty"`
}
// DiscoveryTarget represents all of the inputs necessary to use a resolver
// config entry to execute a catalog query to generate a list of service
// instances during discovery.
type DiscoveryTarget struct {
// ID is a unique identifier for referring to this target in a compiled
// chain. It should be treated as a per-compile opaque string.
ID string `json:",omitempty"`
Service string `json:",omitempty"`
ServiceSubset string `json:",omitempty"`
Namespace string `json:",omitempty"`
Partition string `json:",omitempty"`
Datacenter string `json:",omitempty"`
MeshGateway MeshGatewayConfig `json:",omitempty"`
Subset ServiceResolverSubset `json:",omitempty"`
// External is true if this target is outside of this consul cluster.
External bool `json:",omitempty"`
// SNI is the sni field to use when connecting to this set of endpoints
// over TLS.
SNI string `json:",omitempty"`
// Name is the unique name for this target for use when generating load
// balancer objects. This has a structure similar to SNI, but will not be
// affected by SNI customizations.
Name string `json:",omitempty"`
}
func NewDiscoveryTarget(service, serviceSubset, namespace, datacenter string) *DiscoveryTarget {
t := &DiscoveryTarget{
Service: service,
ServiceSubset: serviceSubset,
Namespace: namespace,
Datacenter: datacenter,
}
t.setID()
return t
}
func chainID(subset, service, namespace, dc string) string {
// NOTE: this format is similar to the SNI syntax for simplicity
if subset == "" {
return fmt.Sprintf("%s.%s.%s", service, namespace, dc)
}
return fmt.Sprintf("%s.%s.%s.%s", subset, service, namespace, dc)
}
func (t *DiscoveryTarget) setID() {
t.ID = chainID(t.ServiceSubset, t.Service, t.Namespace, t.Datacenter)
}
func (t *DiscoveryTarget) String() string {
return t.ID
}
func (t *DiscoveryTarget) ServiceID() ServiceID {
return NewServiceID(t.Service, t.GetEnterpriseMetadata())
}