mirror of https://github.com/hashicorp/consul
353 lines
11 KiB
Go
353 lines
11 KiB
Go
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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// 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 *HTTPServer) 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.EnterpriseMetaInitializer(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.EnterpriseMetaInitializer(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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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.EnterpriseMetaInitializer(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 *HTTPServer) 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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