package consul import ( "fmt" "time" "github.com/armon/go-metrics" "github.com/hashicorp/consul/acl" "github.com/hashicorp/consul/api" "github.com/hashicorp/consul/consul/state" "github.com/hashicorp/consul/consul/structs" "github.com/hashicorp/go-memdb" ) // KVS endpoint is used to manipulate the Key-Value store type KVS struct { srv *Server } // preApply does all the verification of a KVS update that is performed BEFORE // we submit as a Raft log entry. This includes enforcing the lock delay which // must only be done on the leader. func kvsPreApply(srv *Server, acl acl.ACL, op api.KVOp, dirEnt *structs.DirEntry) (bool, error) { // Verify the entry. if dirEnt.Key == "" && op != api.KVDeleteTree { return false, fmt.Errorf("Must provide key") } // Apply the ACL policy if any. if acl != nil { switch op { case api.KVDeleteTree: if !acl.KeyWritePrefix(dirEnt.Key) { return false, errPermissionDenied } case api.KVGet, api.KVGetTree: // Filtering for GETs is done on the output side. case api.KVCheckSession, api.KVCheckIndex: // These could reveal information based on the outcome // of the transaction, and they operate on individual // keys so we check them here. if !acl.KeyRead(dirEnt.Key) { return false, errPermissionDenied } default: if !acl.KeyWrite(dirEnt.Key) { return false, errPermissionDenied } } } // If this is a lock, we must check for a lock-delay. Since lock-delay // is based on wall-time, each peer would expire the lock-delay at a slightly // different time. This means the enforcement of lock-delay cannot be done // after the raft log is committed as it would lead to inconsistent FSMs. // Instead, the lock-delay must be enforced before commit. This means that // only the wall-time of the leader node is used, preventing any inconsistencies. if op == api.KVLock { state := srv.fsm.State() expires := state.KVSLockDelay(dirEnt.Key) if expires.After(time.Now()) { srv.logger.Printf("[WARN] consul.kvs: Rejecting lock of %s due to lock-delay until %v", dirEnt.Key, expires) return false, nil } } return true, nil } // Apply is used to apply a KVS update request to the data store. func (k *KVS) Apply(args *structs.KVSRequest, reply *bool) error { if done, err := k.srv.forward("KVS.Apply", args, args, reply); done { return err } defer metrics.MeasureSince([]string{"consul", "kvs", "apply"}, time.Now()) // Perform the pre-apply checks. acl, err := k.srv.resolveToken(args.Token) if err != nil { return err } ok, err := kvsPreApply(k.srv, acl, args.Op, &args.DirEnt) if err != nil { return err } if !ok { *reply = false return nil } // Apply the update. resp, err := k.srv.raftApply(structs.KVSRequestType, args) if err != nil { k.srv.logger.Printf("[ERR] consul.kvs: Apply failed: %v", err) return err } if respErr, ok := resp.(error); ok { return respErr } // Check if the return type is a bool. if respBool, ok := resp.(bool); ok { *reply = respBool } return nil } // Get is used to lookup a single key. func (k *KVS) Get(args *structs.KeyRequest, reply *structs.IndexedDirEntries) error { if done, err := k.srv.forward("KVS.Get", args, args, reply); done { return err } acl, err := k.srv.resolveToken(args.Token) if err != nil { return err } return k.srv.blockingQuery( &args.QueryOptions, &reply.QueryMeta, func(ws memdb.WatchSet, state *state.Store) error { index, ent, err := state.KVSGet(ws, args.Key) if err != nil { return err } if acl != nil && !acl.KeyRead(args.Key) { ent = nil } if ent == nil { // Must provide non-zero index to prevent blocking // Index 1 is impossible anyways (due to Raft internals) if index == 0 { reply.Index = 1 } else { reply.Index = index } reply.Entries = nil } else { reply.Index = ent.ModifyIndex reply.Entries = structs.DirEntries{ent} } return nil }) } // List is used to list all keys with a given prefix. func (k *KVS) List(args *structs.KeyRequest, reply *structs.IndexedDirEntries) error { if done, err := k.srv.forward("KVS.List", args, args, reply); done { return err } acl, err := k.srv.resolveToken(args.Token) if err != nil { return err } return k.srv.blockingQuery( &args.QueryOptions, &reply.QueryMeta, func(ws memdb.WatchSet, state *state.Store) error { index, ent, err := state.KVSList(ws, args.Key) if err != nil { return err } if acl != nil { ent = FilterDirEnt(acl, ent) } if len(ent) == 0 { // Must provide non-zero index to prevent blocking // Index 1 is impossible anyways (due to Raft internals) if index == 0 { reply.Index = 1 } else { reply.Index = index } reply.Entries = nil } else { reply.Index = index reply.Entries = ent } return nil }) } // ListKeys is used to list all keys with a given prefix to a separator. func (k *KVS) ListKeys(args *structs.KeyListRequest, reply *structs.IndexedKeyList) error { if done, err := k.srv.forward("KVS.ListKeys", args, args, reply); done { return err } acl, err := k.srv.resolveToken(args.Token) if err != nil { return err } return k.srv.blockingQuery( &args.QueryOptions, &reply.QueryMeta, func(ws memdb.WatchSet, state *state.Store) error { index, keys, err := state.KVSListKeys(ws, args.Prefix, args.Seperator) if err != nil { return err } // Must provide non-zero index to prevent blocking // Index 1 is impossible anyways (due to Raft internals) if index == 0 { reply.Index = 1 } else { reply.Index = index } if acl != nil { keys = FilterKeys(acl, keys) } reply.Keys = keys return nil }) }