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353 lines
11 KiB
353 lines
11 KiB
package agent |
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import ( |
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"encoding/base64" |
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"fmt" |
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"net/http" |
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"strings" |
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"time" |
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"github.com/hashicorp/consul/agent/structs" |
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"github.com/hashicorp/consul/api" |
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"github.com/hashicorp/consul/types" |
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) |
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const ( |
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// maxTxnOps is used to set an upper limit on the number of operations |
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// inside a transaction. If there are more operations than this, then the |
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// client is likely abusing transactions. |
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maxTxnOps = 64 |
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) |
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// decodeValue decodes the value member of the given operation. |
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func decodeValue(rawKV interface{}) error { |
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rawMap, ok := rawKV.(map[string]interface{}) |
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if !ok { |
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return fmt.Errorf("unexpected raw KV type: %T", rawKV) |
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} |
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for k, v := range rawMap { |
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switch strings.ToLower(k) { |
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case "value": |
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// Leave the byte slice nil if we have a nil |
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// value. |
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if v == nil { |
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return nil |
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} |
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|
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// Otherwise, base64 decode it. |
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s, ok := v.(string) |
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if !ok { |
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return fmt.Errorf("unexpected value type: %T", v) |
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} |
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decoded, err := base64.StdEncoding.DecodeString(s) |
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if err != nil { |
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return fmt.Errorf("failed to decode value: %v", err) |
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} |
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rawMap[k] = decoded |
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return nil |
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} |
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} |
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return nil |
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} |
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// isWrite returns true if the given operation alters the state store. |
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func isWrite(op api.KVOp) bool { |
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switch op { |
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case api.KVSet, api.KVDelete, api.KVDeleteCAS, api.KVDeleteTree, api.KVCAS, api.KVLock, api.KVUnlock: |
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return true |
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} |
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return false |
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} |
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// convertOps takes the incoming body in API format and converts it to the |
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// internal RPC format. This returns a count of the number of write ops, and |
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// a boolean, that if false means an error response has been generated and |
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// processing should stop. |
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func (s *HTTPHandlers) convertOps(resp http.ResponseWriter, req *http.Request) (structs.TxnOps, int, bool) { |
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// The TxnMaxReqLen limit and KVMaxValueSize limit both default to the |
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// suggested raft data size and can be configured independently. The |
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// TxnMaxReqLen is enforced on the cumulative size of the transaction, |
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// whereas the KVMaxValueSize limit is imposed on the values of individual KV |
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// operations -- this is to keep consistent with the behavior for KV values |
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// in the kvs endpoint. |
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// |
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// The defaults are set to the suggested raft size to keep the total |
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// transaction size reasonable to account for timely heartbeat signals. If |
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// the TxnMaxReqLen limit is above the raft's suggested threshold, large |
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// transactions are automatically set to attempt a chunking apply. |
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// Performance may degrade and warning messages may appear. |
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maxTxnLen := int64(s.agent.config.TxnMaxReqLen) |
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kvMaxValueSize := int64(s.agent.config.KVMaxValueSize) |
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// For backward compatibility, KVMaxValueSize is used as the max txn request |
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// length if it is configured greater than TxnMaxReqLen or its default |
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if maxTxnLen < kvMaxValueSize { |
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maxTxnLen = kvMaxValueSize |
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} |
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// Check Content-Length first before decoding to return early |
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if req.ContentLength > maxTxnLen { |
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resp.WriteHeader(http.StatusRequestEntityTooLarge) |
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fmt.Fprintf(resp, |
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"Request body(%d bytes) too large, max size: %d bytes. See %s.", |
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req.ContentLength, maxTxnLen, |
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"https://www.consul.io/docs/agent/options.html#txn_max_req_len", |
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) |
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return nil, 0, false |
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} |
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var ops api.TxnOps |
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req.Body = http.MaxBytesReader(resp, req.Body, maxTxnLen) |
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if err := decodeBody(req.Body, &ops); err != nil { |
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if err.Error() == "http: request body too large" { |
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// The request size is also verified during decoding to double check |
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// if the Content-Length header was not set by the client. |
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resp.WriteHeader(http.StatusRequestEntityTooLarge) |
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fmt.Fprintf(resp, |
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"Request body too large, max size: %d bytes. See %s.", |
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maxTxnLen, |
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"https://www.consul.io/docs/agent/options.html#txn_max_req_len", |
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) |
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} else { |
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// Note the body is in API format, and not the RPC format. If we can't |
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// decode it, we will return a 400 since we don't have enough context to |
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// associate the error with a given operation. |
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resp.WriteHeader(http.StatusBadRequest) |
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fmt.Fprintf(resp, "Failed to parse body: %v", err) |
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} |
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return nil, 0, false |
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} |
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// Enforce a reasonable upper limit on the number of operations in a |
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// transaction in order to curb abuse. |
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if size := len(ops); size > maxTxnOps { |
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resp.WriteHeader(http.StatusRequestEntityTooLarge) |
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fmt.Fprintf(resp, "Transaction contains too many operations (%d > %d)", |
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size, maxTxnOps) |
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return nil, 0, false |
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} |
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// Convert the KV API format into the RPC format. Note that fixupKVOps |
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// above will have already converted the base64 encoded strings into |
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// byte arrays so we can assign right over. |
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var opsRPC structs.TxnOps |
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var writes int |
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for _, in := range ops { |
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switch { |
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case in.KV != nil: |
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size := len(in.KV.Value) |
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if int64(size) > kvMaxValueSize { |
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resp.WriteHeader(http.StatusRequestEntityTooLarge) |
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fmt.Fprintf(resp, "Value for key %q is too large (%d > %d bytes)", in.KV.Key, size, s.agent.config.KVMaxValueSize) |
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return nil, 0, false |
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} |
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verb := in.KV.Verb |
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if isWrite(verb) { |
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writes++ |
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} |
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out := &structs.TxnOp{ |
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KV: &structs.TxnKVOp{ |
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Verb: verb, |
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DirEnt: structs.DirEntry{ |
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Key: in.KV.Key, |
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Value: in.KV.Value, |
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Flags: in.KV.Flags, |
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Session: in.KV.Session, |
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EnterpriseMeta: structs.NewEnterpriseMeta(in.KV.Namespace), |
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RaftIndex: structs.RaftIndex{ |
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ModifyIndex: in.KV.Index, |
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}, |
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}, |
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}, |
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} |
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opsRPC = append(opsRPC, out) |
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case in.Node != nil: |
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if in.Node.Verb != api.NodeGet { |
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writes++ |
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} |
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// Setup the default DC if not provided |
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if in.Node.Node.Datacenter == "" { |
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in.Node.Node.Datacenter = s.agent.config.Datacenter |
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} |
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node := in.Node.Node |
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out := &structs.TxnOp{ |
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Node: &structs.TxnNodeOp{ |
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Verb: in.Node.Verb, |
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Node: structs.Node{ |
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ID: types.NodeID(node.ID), |
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Node: node.Node, |
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Address: node.Address, |
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Datacenter: node.Datacenter, |
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TaggedAddresses: node.TaggedAddresses, |
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Meta: node.Meta, |
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RaftIndex: structs.RaftIndex{ |
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ModifyIndex: node.ModifyIndex, |
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}, |
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}, |
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}, |
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} |
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opsRPC = append(opsRPC, out) |
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case in.Service != nil: |
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if in.Service.Verb != api.ServiceGet { |
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writes++ |
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} |
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svc := in.Service.Service |
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out := &structs.TxnOp{ |
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Service: &structs.TxnServiceOp{ |
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Verb: in.Service.Verb, |
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Node: in.Service.Node, |
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Service: structs.NodeService{ |
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ID: svc.ID, |
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Service: svc.Service, |
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Tags: svc.Tags, |
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Address: svc.Address, |
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Meta: svc.Meta, |
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Port: svc.Port, |
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Weights: &structs.Weights{ |
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Passing: svc.Weights.Passing, |
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Warning: svc.Weights.Warning, |
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}, |
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EnableTagOverride: svc.EnableTagOverride, |
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EnterpriseMeta: structs.NewEnterpriseMeta(svc.Namespace), |
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RaftIndex: structs.RaftIndex{ |
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ModifyIndex: svc.ModifyIndex, |
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}, |
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}, |
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}, |
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} |
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opsRPC = append(opsRPC, out) |
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case in.Check != nil: |
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if in.Check.Verb != api.CheckGet { |
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writes++ |
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} |
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check := in.Check.Check |
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// Check if the internal duration fields are set as well as the normal ones. This is |
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// to be backwards compatible with a bug where the internal duration fields were being |
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// deserialized from instead of the correct fields. |
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// See https://github.com/hashicorp/consul/issues/5477 for more details. |
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interval := check.Definition.IntervalDuration |
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if dur := time.Duration(check.Definition.Interval); dur != 0 { |
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interval = dur |
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} |
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timeout := check.Definition.TimeoutDuration |
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if dur := time.Duration(check.Definition.Timeout); dur != 0 { |
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timeout = dur |
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} |
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deregisterCriticalServiceAfter := check.Definition.DeregisterCriticalServiceAfterDuration |
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if dur := time.Duration(check.Definition.DeregisterCriticalServiceAfter); dur != 0 { |
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deregisterCriticalServiceAfter = dur |
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} |
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out := &structs.TxnOp{ |
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Check: &structs.TxnCheckOp{ |
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Verb: in.Check.Verb, |
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Check: structs.HealthCheck{ |
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Node: check.Node, |
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CheckID: types.CheckID(check.CheckID), |
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Name: check.Name, |
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Status: check.Status, |
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Notes: check.Notes, |
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Output: check.Output, |
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ServiceID: check.ServiceID, |
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ServiceName: check.ServiceName, |
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ServiceTags: check.ServiceTags, |
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Definition: structs.HealthCheckDefinition{ |
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HTTP: check.Definition.HTTP, |
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TLSServerName: check.Definition.TLSServerName, |
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TLSSkipVerify: check.Definition.TLSSkipVerify, |
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Header: check.Definition.Header, |
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Method: check.Definition.Method, |
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Body: check.Definition.Body, |
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TCP: check.Definition.TCP, |
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Interval: interval, |
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Timeout: timeout, |
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DeregisterCriticalServiceAfter: deregisterCriticalServiceAfter, |
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}, |
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EnterpriseMeta: structs.NewEnterpriseMeta(check.Namespace), |
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RaftIndex: structs.RaftIndex{ |
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ModifyIndex: check.ModifyIndex, |
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}, |
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}, |
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}, |
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} |
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opsRPC = append(opsRPC, out) |
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} |
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} |
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return opsRPC, writes, true |
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} |
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// Txn handles requests to apply multiple operations in a single, atomic |
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// transaction. A transaction consisting of only read operations will be fast- |
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// pathed to an endpoint that supports consistency modes (but not blocking), |
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// and everything else will be routed through Raft like a normal write. |
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func (s *HTTPHandlers) Txn(resp http.ResponseWriter, req *http.Request) (interface{}, error) { |
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// Convert the ops from the API format to the internal format. |
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ops, writes, ok := s.convertOps(resp, req) |
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if !ok { |
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return nil, nil |
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} |
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// Fast-path a transaction with only writes to the read-only endpoint, |
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// which bypasses Raft, and allows for staleness. |
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conflict := false |
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var ret interface{} |
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if writes == 0 { |
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args := structs.TxnReadRequest{Ops: ops} |
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if done := s.parse(resp, req, &args.Datacenter, &args.QueryOptions); done { |
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return nil, nil |
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} |
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var reply structs.TxnReadResponse |
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if err := s.agent.RPC("Txn.Read", &args, &reply); err != nil { |
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return nil, err |
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} |
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// Since we don't do blocking, we only add the relevant headers |
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// for metadata. |
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setLastContact(resp, reply.LastContact) |
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setKnownLeader(resp, reply.KnownLeader) |
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ret, conflict = reply, len(reply.Errors) > 0 |
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} else { |
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args := structs.TxnRequest{Ops: ops} |
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s.parseDC(req, &args.Datacenter) |
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s.parseToken(req, &args.Token) |
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var reply structs.TxnResponse |
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if err := s.agent.RPC("Txn.Apply", &args, &reply); err != nil { |
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return nil, err |
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} |
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ret, conflict = reply, len(reply.Errors) > 0 |
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} |
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// If there was a conflict return the response object but set a special |
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// status code. |
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if conflict { |
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var buf []byte |
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var err error |
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buf, err = s.marshalJSON(req, ret) |
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if err != nil { |
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return nil, err |
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} |
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resp.Header().Set("Content-Type", "application/json") |
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resp.WriteHeader(http.StatusConflict) |
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resp.Write(buf) |
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return nil, nil |
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} |
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// Otherwise, return the results of the successful transaction. |
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return ret, nil |
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}
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