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