open-consul/agent/consul/discovery_chain_endpoint.go

106 lines
2.8 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package consul
import (
"fmt"
"time"
metrics "github.com/armon/go-metrics"
memdb "github.com/hashicorp/go-memdb"
hashstructure_v2 "github.com/mitchellh/hashstructure/v2"
"github.com/hashicorp/consul/acl"
"github.com/hashicorp/consul/agent/consul/discoverychain"
"github.com/hashicorp/consul/agent/consul/state"
"github.com/hashicorp/consul/agent/structs"
)
type DiscoveryChain struct {
srv *Server
}
func (c *DiscoveryChain) Get(args *structs.DiscoveryChainRequest, reply *structs.DiscoveryChainResponse) error {
// Exit early if Connect hasn't been enabled.
if !c.srv.config.ConnectEnabled {
return ErrConnectNotEnabled
}
if done, err := c.srv.ForwardRPC("DiscoveryChain.Get", args, reply); done {
return err
}
defer metrics.MeasureSince([]string{"discovery_chain", "get"}, time.Now())
// Fetch the ACL token, if any.
entMeta := args.GetEnterpriseMeta()
var authzContext acl.AuthorizerContext
authz, err := c.srv.ResolveTokenAndDefaultMeta(args.Token, entMeta, &authzContext)
if err != nil {
return err
}
if err := authz.ToAllowAuthorizer().ServiceReadAllowed(args.Name, &authzContext); err != nil {
return err
}
if args.Name == "" {
return fmt.Errorf("Must provide service name")
}
evalDC := args.EvaluateInDatacenter
if evalDC == "" {
evalDC = c.srv.config.Datacenter
}
var (
priorHash uint64
ranOnce bool
)
return c.srv.blockingQuery(
&args.QueryOptions,
&reply.QueryMeta,
func(ws memdb.WatchSet, state *state.Store) error {
req := discoverychain.CompileRequest{
ServiceName: args.Name,
EvaluateInNamespace: entMeta.NamespaceOrDefault(),
EvaluateInPartition: entMeta.PartitionOrDefault(),
EvaluateInDatacenter: evalDC,
OverrideMeshGateway: args.OverrideMeshGateway,
OverrideProtocol: args.OverrideProtocol,
OverrideConnectTimeout: args.OverrideConnectTimeout,
}
index, chain, entries, err := state.ServiceDiscoveryChain(ws, args.Name, entMeta, req)
if err != nil {
return err
}
// Generate a hash of the config entry content driving this
// response. Use it to determine if the response is identical to a
// prior wakeup.
newHash, err := hashstructure_v2.Hash(chain, hashstructure_v2.FormatV2, nil)
if err != nil {
return fmt.Errorf("error hashing reply for spurious wakeup suppression: %w", err)
}
if ranOnce && priorHash == newHash {
priorHash = newHash
reply.Index = index
// NOTE: the prior response is still alive inside of *reply, which
// is desirable
return errNotChanged
} else {
priorHash = newHash
ranOnce = true
}
reply.Index = index
reply.Chain = chain
if entries.IsEmpty() {
return errNotFound
}
return nil
})
}