khenaidoo | d948f77 | 2021-08-11 17:49:24 -0400 | [diff] [blame] | 1 | // Copyright 2015 The etcd Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package rafthttp |
| 16 | |
| 17 | import ( |
| 18 | "fmt" |
| 19 | "io" |
| 20 | "net" |
| 21 | "net/http" |
| 22 | "net/url" |
| 23 | "strings" |
| 24 | "time" |
| 25 | |
| 26 | "github.com/coreos/etcd/pkg/transport" |
| 27 | "github.com/coreos/etcd/pkg/types" |
| 28 | "github.com/coreos/etcd/version" |
| 29 | "github.com/coreos/go-semver/semver" |
| 30 | ) |
| 31 | |
| 32 | var ( |
| 33 | errMemberRemoved = fmt.Errorf("the member has been permanently removed from the cluster") |
| 34 | errMemberNotFound = fmt.Errorf("member not found") |
| 35 | ) |
| 36 | |
| 37 | // NewListener returns a listener for raft message transfer between peers. |
| 38 | // It uses timeout listener to identify broken streams promptly. |
| 39 | func NewListener(u url.URL, tlsinfo *transport.TLSInfo) (net.Listener, error) { |
| 40 | return transport.NewTimeoutListener(u.Host, u.Scheme, tlsinfo, ConnReadTimeout, ConnWriteTimeout) |
| 41 | } |
| 42 | |
| 43 | // NewRoundTripper returns a roundTripper used to send requests |
| 44 | // to rafthttp listener of remote peers. |
| 45 | func NewRoundTripper(tlsInfo transport.TLSInfo, dialTimeout time.Duration) (http.RoundTripper, error) { |
| 46 | // It uses timeout transport to pair with remote timeout listeners. |
| 47 | // It sets no read/write timeout, because message in requests may |
| 48 | // take long time to write out before reading out the response. |
| 49 | return transport.NewTimeoutTransport(tlsInfo, dialTimeout, 0, 0) |
| 50 | } |
| 51 | |
| 52 | // newStreamRoundTripper returns a roundTripper used to send stream requests |
| 53 | // to rafthttp listener of remote peers. |
| 54 | // Read/write timeout is set for stream roundTripper to promptly |
| 55 | // find out broken status, which minimizes the number of messages |
| 56 | // sent on broken connection. |
| 57 | func newStreamRoundTripper(tlsInfo transport.TLSInfo, dialTimeout time.Duration) (http.RoundTripper, error) { |
| 58 | return transport.NewTimeoutTransport(tlsInfo, dialTimeout, ConnReadTimeout, ConnWriteTimeout) |
| 59 | } |
| 60 | |
| 61 | // createPostRequest creates a HTTP POST request that sends raft message. |
| 62 | func createPostRequest(u url.URL, path string, body io.Reader, ct string, urls types.URLs, from, cid types.ID) *http.Request { |
| 63 | uu := u |
| 64 | uu.Path = path |
| 65 | req, err := http.NewRequest("POST", uu.String(), body) |
| 66 | if err != nil { |
| 67 | plog.Panicf("unexpected new request error (%v)", err) |
| 68 | } |
| 69 | req.Header.Set("Content-Type", ct) |
| 70 | req.Header.Set("X-Server-From", from.String()) |
| 71 | req.Header.Set("X-Server-Version", version.Version) |
| 72 | req.Header.Set("X-Min-Cluster-Version", version.MinClusterVersion) |
| 73 | req.Header.Set("X-Etcd-Cluster-ID", cid.String()) |
| 74 | setPeerURLsHeader(req, urls) |
| 75 | |
| 76 | return req |
| 77 | } |
| 78 | |
| 79 | // checkPostResponse checks the response of the HTTP POST request that sends |
| 80 | // raft message. |
| 81 | func checkPostResponse(resp *http.Response, body []byte, req *http.Request, to types.ID) error { |
| 82 | switch resp.StatusCode { |
| 83 | case http.StatusPreconditionFailed: |
| 84 | switch strings.TrimSuffix(string(body), "\n") { |
| 85 | case errIncompatibleVersion.Error(): |
| 86 | plog.Errorf("request sent was ignored by peer %s (server version incompatible)", to) |
| 87 | return errIncompatibleVersion |
| 88 | case errClusterIDMismatch.Error(): |
| 89 | plog.Errorf("request sent was ignored (cluster ID mismatch: remote[%s]=%s, local=%s)", |
| 90 | to, resp.Header.Get("X-Etcd-Cluster-ID"), req.Header.Get("X-Etcd-Cluster-ID")) |
| 91 | return errClusterIDMismatch |
| 92 | default: |
| 93 | return fmt.Errorf("unhandled error %q when precondition failed", string(body)) |
| 94 | } |
| 95 | case http.StatusForbidden: |
| 96 | return errMemberRemoved |
| 97 | case http.StatusNoContent: |
| 98 | return nil |
| 99 | default: |
| 100 | return fmt.Errorf("unexpected http status %s while posting to %q", http.StatusText(resp.StatusCode), req.URL.String()) |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | // reportCriticalError reports the given error through sending it into |
| 105 | // the given error channel. |
| 106 | // If the error channel is filled up when sending error, it drops the error |
| 107 | // because the fact that error has happened is reported, which is |
| 108 | // good enough. |
| 109 | func reportCriticalError(err error, errc chan<- error) { |
| 110 | select { |
| 111 | case errc <- err: |
| 112 | default: |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | // compareMajorMinorVersion returns an integer comparing two versions based on |
| 117 | // their major and minor version. The result will be 0 if a==b, -1 if a < b, |
| 118 | // and 1 if a > b. |
| 119 | func compareMajorMinorVersion(a, b *semver.Version) int { |
| 120 | na := &semver.Version{Major: a.Major, Minor: a.Minor} |
| 121 | nb := &semver.Version{Major: b.Major, Minor: b.Minor} |
| 122 | switch { |
| 123 | case na.LessThan(*nb): |
| 124 | return -1 |
| 125 | case nb.LessThan(*na): |
| 126 | return 1 |
| 127 | default: |
| 128 | return 0 |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | // serverVersion returns the server version from the given header. |
| 133 | func serverVersion(h http.Header) *semver.Version { |
| 134 | verStr := h.Get("X-Server-Version") |
| 135 | // backward compatibility with etcd 2.0 |
| 136 | if verStr == "" { |
| 137 | verStr = "2.0.0" |
| 138 | } |
| 139 | return semver.Must(semver.NewVersion(verStr)) |
| 140 | } |
| 141 | |
| 142 | // serverVersion returns the min cluster version from the given header. |
| 143 | func minClusterVersion(h http.Header) *semver.Version { |
| 144 | verStr := h.Get("X-Min-Cluster-Version") |
| 145 | // backward compatibility with etcd 2.0 |
| 146 | if verStr == "" { |
| 147 | verStr = "2.0.0" |
| 148 | } |
| 149 | return semver.Must(semver.NewVersion(verStr)) |
| 150 | } |
| 151 | |
| 152 | // checkVersionCompability checks whether the given version is compatible |
| 153 | // with the local version. |
| 154 | func checkVersionCompability(name string, server, minCluster *semver.Version) error { |
| 155 | localServer := semver.Must(semver.NewVersion(version.Version)) |
| 156 | localMinCluster := semver.Must(semver.NewVersion(version.MinClusterVersion)) |
| 157 | if compareMajorMinorVersion(server, localMinCluster) == -1 { |
| 158 | return fmt.Errorf("remote version is too low: remote[%s]=%s, local=%s", name, server, localServer) |
| 159 | } |
| 160 | if compareMajorMinorVersion(minCluster, localServer) == 1 { |
| 161 | return fmt.Errorf("local version is too low: remote[%s]=%s, local=%s", name, server, localServer) |
| 162 | } |
| 163 | return nil |
| 164 | } |
| 165 | |
| 166 | // setPeerURLsHeader reports local urls for peer discovery |
| 167 | func setPeerURLsHeader(req *http.Request, urls types.URLs) { |
| 168 | if urls == nil { |
| 169 | // often not set in unit tests |
| 170 | return |
| 171 | } |
| 172 | peerURLs := make([]string, urls.Len()) |
| 173 | for i := range urls { |
| 174 | peerURLs[i] = urls[i].String() |
| 175 | } |
| 176 | req.Header.Set("X-PeerURLs", strings.Join(peerURLs, ",")) |
| 177 | } |
| 178 | |
| 179 | // addRemoteFromRequest adds a remote peer according to an http request header |
| 180 | func addRemoteFromRequest(tr Transporter, r *http.Request) { |
| 181 | if from, err := types.IDFromString(r.Header.Get("X-Server-From")); err == nil { |
| 182 | if urls := r.Header.Get("X-PeerURLs"); urls != "" { |
| 183 | tr.AddRemote(from, strings.Split(urls, ",")) |
| 184 | } |
| 185 | } |
| 186 | } |