khenaidoo | ac63710 | 2019-01-14 15:44:34 -0500 | [diff] [blame] | 1 | package api |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "fmt" |
| 6 | "io" |
| 7 | "net/http" |
| 8 | "strconv" |
| 9 | "strings" |
| 10 | ) |
| 11 | |
| 12 | // KVPair is used to represent a single K/V entry |
| 13 | type KVPair struct { |
| 14 | // Key is the name of the key. It is also part of the URL path when accessed |
| 15 | // via the API. |
| 16 | Key string |
| 17 | |
| 18 | // CreateIndex holds the index corresponding the creation of this KVPair. This |
| 19 | // is a read-only field. |
| 20 | CreateIndex uint64 |
| 21 | |
| 22 | // ModifyIndex is used for the Check-And-Set operations and can also be fed |
| 23 | // back into the WaitIndex of the QueryOptions in order to perform blocking |
| 24 | // queries. |
| 25 | ModifyIndex uint64 |
| 26 | |
| 27 | // LockIndex holds the index corresponding to a lock on this key, if any. This |
| 28 | // is a read-only field. |
| 29 | LockIndex uint64 |
| 30 | |
| 31 | // Flags are any user-defined flags on the key. It is up to the implementer |
| 32 | // to check these values, since Consul does not treat them specially. |
| 33 | Flags uint64 |
| 34 | |
| 35 | // Value is the value for the key. This can be any value, but it will be |
| 36 | // base64 encoded upon transport. |
| 37 | Value []byte |
| 38 | |
| 39 | // Session is a string representing the ID of the session. Any other |
| 40 | // interactions with this key over the same session must specify the same |
| 41 | // session ID. |
| 42 | Session string |
| 43 | } |
| 44 | |
| 45 | // KVPairs is a list of KVPair objects |
| 46 | type KVPairs []*KVPair |
| 47 | |
| 48 | // KVOp constants give possible operations available in a KVTxn. |
| 49 | type KVOp string |
| 50 | |
| 51 | const ( |
| 52 | KVSet KVOp = "set" |
| 53 | KVDelete KVOp = "delete" |
| 54 | KVDeleteCAS KVOp = "delete-cas" |
| 55 | KVDeleteTree KVOp = "delete-tree" |
| 56 | KVCAS KVOp = "cas" |
| 57 | KVLock KVOp = "lock" |
| 58 | KVUnlock KVOp = "unlock" |
| 59 | KVGet KVOp = "get" |
| 60 | KVGetTree KVOp = "get-tree" |
| 61 | KVCheckSession KVOp = "check-session" |
| 62 | KVCheckIndex KVOp = "check-index" |
| 63 | KVCheckNotExists KVOp = "check-not-exists" |
| 64 | ) |
| 65 | |
| 66 | // KVTxnOp defines a single operation inside a transaction. |
| 67 | type KVTxnOp struct { |
| 68 | Verb KVOp |
| 69 | Key string |
| 70 | Value []byte |
| 71 | Flags uint64 |
| 72 | Index uint64 |
| 73 | Session string |
| 74 | } |
| 75 | |
| 76 | // KVTxnOps defines a set of operations to be performed inside a single |
| 77 | // transaction. |
| 78 | type KVTxnOps []*KVTxnOp |
| 79 | |
| 80 | // KVTxnResponse has the outcome of a transaction. |
| 81 | type KVTxnResponse struct { |
| 82 | Results []*KVPair |
| 83 | Errors TxnErrors |
| 84 | } |
| 85 | |
| 86 | // KV is used to manipulate the K/V API |
| 87 | type KV struct { |
| 88 | c *Client |
| 89 | } |
| 90 | |
| 91 | // KV is used to return a handle to the K/V apis |
| 92 | func (c *Client) KV() *KV { |
| 93 | return &KV{c} |
| 94 | } |
| 95 | |
| 96 | // Get is used to lookup a single key. The returned pointer |
| 97 | // to the KVPair will be nil if the key does not exist. |
| 98 | func (k *KV) Get(key string, q *QueryOptions) (*KVPair, *QueryMeta, error) { |
| 99 | resp, qm, err := k.getInternal(key, nil, q) |
| 100 | if err != nil { |
| 101 | return nil, nil, err |
| 102 | } |
| 103 | if resp == nil { |
| 104 | return nil, qm, nil |
| 105 | } |
| 106 | defer resp.Body.Close() |
| 107 | |
| 108 | var entries []*KVPair |
| 109 | if err := decodeBody(resp, &entries); err != nil { |
| 110 | return nil, nil, err |
| 111 | } |
| 112 | if len(entries) > 0 { |
| 113 | return entries[0], qm, nil |
| 114 | } |
| 115 | return nil, qm, nil |
| 116 | } |
| 117 | |
| 118 | // List is used to lookup all keys under a prefix |
| 119 | func (k *KV) List(prefix string, q *QueryOptions) (KVPairs, *QueryMeta, error) { |
| 120 | resp, qm, err := k.getInternal(prefix, map[string]string{"recurse": ""}, q) |
| 121 | if err != nil { |
| 122 | return nil, nil, err |
| 123 | } |
| 124 | if resp == nil { |
| 125 | return nil, qm, nil |
| 126 | } |
| 127 | defer resp.Body.Close() |
| 128 | |
| 129 | var entries []*KVPair |
| 130 | if err := decodeBody(resp, &entries); err != nil { |
| 131 | return nil, nil, err |
| 132 | } |
| 133 | return entries, qm, nil |
| 134 | } |
| 135 | |
| 136 | // Keys is used to list all the keys under a prefix. Optionally, |
| 137 | // a separator can be used to limit the responses. |
| 138 | func (k *KV) Keys(prefix, separator string, q *QueryOptions) ([]string, *QueryMeta, error) { |
| 139 | params := map[string]string{"keys": ""} |
| 140 | if separator != "" { |
| 141 | params["separator"] = separator |
| 142 | } |
| 143 | resp, qm, err := k.getInternal(prefix, params, q) |
| 144 | if err != nil { |
| 145 | return nil, nil, err |
| 146 | } |
| 147 | if resp == nil { |
| 148 | return nil, qm, nil |
| 149 | } |
| 150 | defer resp.Body.Close() |
| 151 | |
| 152 | var entries []string |
| 153 | if err := decodeBody(resp, &entries); err != nil { |
| 154 | return nil, nil, err |
| 155 | } |
| 156 | return entries, qm, nil |
| 157 | } |
| 158 | |
| 159 | func (k *KV) getInternal(key string, params map[string]string, q *QueryOptions) (*http.Response, *QueryMeta, error) { |
| 160 | r := k.c.newRequest("GET", "/v1/kv/"+strings.TrimPrefix(key, "/")) |
| 161 | r.setQueryOptions(q) |
| 162 | for param, val := range params { |
| 163 | r.params.Set(param, val) |
| 164 | } |
| 165 | rtt, resp, err := k.c.doRequest(r) |
| 166 | if err != nil { |
| 167 | return nil, nil, err |
| 168 | } |
| 169 | |
| 170 | qm := &QueryMeta{} |
| 171 | parseQueryMeta(resp, qm) |
| 172 | qm.RequestTime = rtt |
| 173 | |
| 174 | if resp.StatusCode == 404 { |
| 175 | resp.Body.Close() |
| 176 | return nil, qm, nil |
| 177 | } else if resp.StatusCode != 200 { |
| 178 | resp.Body.Close() |
| 179 | return nil, nil, fmt.Errorf("Unexpected response code: %d", resp.StatusCode) |
| 180 | } |
| 181 | return resp, qm, nil |
| 182 | } |
| 183 | |
| 184 | // Put is used to write a new value. Only the |
| 185 | // Key, Flags and Value is respected. |
| 186 | func (k *KV) Put(p *KVPair, q *WriteOptions) (*WriteMeta, error) { |
| 187 | params := make(map[string]string, 1) |
| 188 | if p.Flags != 0 { |
| 189 | params["flags"] = strconv.FormatUint(p.Flags, 10) |
| 190 | } |
| 191 | _, wm, err := k.put(p.Key, params, p.Value, q) |
| 192 | return wm, err |
| 193 | } |
| 194 | |
| 195 | // CAS is used for a Check-And-Set operation. The Key, |
| 196 | // ModifyIndex, Flags and Value are respected. Returns true |
| 197 | // on success or false on failures. |
| 198 | func (k *KV) CAS(p *KVPair, q *WriteOptions) (bool, *WriteMeta, error) { |
| 199 | params := make(map[string]string, 2) |
| 200 | if p.Flags != 0 { |
| 201 | params["flags"] = strconv.FormatUint(p.Flags, 10) |
| 202 | } |
| 203 | params["cas"] = strconv.FormatUint(p.ModifyIndex, 10) |
| 204 | return k.put(p.Key, params, p.Value, q) |
| 205 | } |
| 206 | |
| 207 | // Acquire is used for a lock acquisition operation. The Key, |
| 208 | // Flags, Value and Session are respected. Returns true |
| 209 | // on success or false on failures. |
| 210 | func (k *KV) Acquire(p *KVPair, q *WriteOptions) (bool, *WriteMeta, error) { |
| 211 | params := make(map[string]string, 2) |
| 212 | if p.Flags != 0 { |
| 213 | params["flags"] = strconv.FormatUint(p.Flags, 10) |
| 214 | } |
| 215 | params["acquire"] = p.Session |
| 216 | return k.put(p.Key, params, p.Value, q) |
| 217 | } |
| 218 | |
| 219 | // Release is used for a lock release operation. The Key, |
| 220 | // Flags, Value and Session are respected. Returns true |
| 221 | // on success or false on failures. |
| 222 | func (k *KV) Release(p *KVPair, q *WriteOptions) (bool, *WriteMeta, error) { |
| 223 | params := make(map[string]string, 2) |
| 224 | if p.Flags != 0 { |
| 225 | params["flags"] = strconv.FormatUint(p.Flags, 10) |
| 226 | } |
| 227 | params["release"] = p.Session |
| 228 | return k.put(p.Key, params, p.Value, q) |
| 229 | } |
| 230 | |
| 231 | func (k *KV) put(key string, params map[string]string, body []byte, q *WriteOptions) (bool, *WriteMeta, error) { |
| 232 | if len(key) > 0 && key[0] == '/' { |
| 233 | return false, nil, fmt.Errorf("Invalid key. Key must not begin with a '/': %s", key) |
| 234 | } |
| 235 | |
| 236 | r := k.c.newRequest("PUT", "/v1/kv/"+key) |
| 237 | r.setWriteOptions(q) |
| 238 | for param, val := range params { |
| 239 | r.params.Set(param, val) |
| 240 | } |
| 241 | r.body = bytes.NewReader(body) |
| 242 | rtt, resp, err := requireOK(k.c.doRequest(r)) |
| 243 | if err != nil { |
| 244 | return false, nil, err |
| 245 | } |
| 246 | defer resp.Body.Close() |
| 247 | |
| 248 | qm := &WriteMeta{} |
| 249 | qm.RequestTime = rtt |
| 250 | |
| 251 | var buf bytes.Buffer |
| 252 | if _, err := io.Copy(&buf, resp.Body); err != nil { |
| 253 | return false, nil, fmt.Errorf("Failed to read response: %v", err) |
| 254 | } |
| 255 | res := strings.Contains(buf.String(), "true") |
| 256 | return res, qm, nil |
| 257 | } |
| 258 | |
| 259 | // Delete is used to delete a single key |
| 260 | func (k *KV) Delete(key string, w *WriteOptions) (*WriteMeta, error) { |
| 261 | _, qm, err := k.deleteInternal(key, nil, w) |
| 262 | return qm, err |
| 263 | } |
| 264 | |
| 265 | // DeleteCAS is used for a Delete Check-And-Set operation. The Key |
| 266 | // and ModifyIndex are respected. Returns true on success or false on failures. |
| 267 | func (k *KV) DeleteCAS(p *KVPair, q *WriteOptions) (bool, *WriteMeta, error) { |
| 268 | params := map[string]string{ |
| 269 | "cas": strconv.FormatUint(p.ModifyIndex, 10), |
| 270 | } |
| 271 | return k.deleteInternal(p.Key, params, q) |
| 272 | } |
| 273 | |
| 274 | // DeleteTree is used to delete all keys under a prefix |
| 275 | func (k *KV) DeleteTree(prefix string, w *WriteOptions) (*WriteMeta, error) { |
| 276 | _, qm, err := k.deleteInternal(prefix, map[string]string{"recurse": ""}, w) |
| 277 | return qm, err |
| 278 | } |
| 279 | |
| 280 | func (k *KV) deleteInternal(key string, params map[string]string, q *WriteOptions) (bool, *WriteMeta, error) { |
| 281 | r := k.c.newRequest("DELETE", "/v1/kv/"+strings.TrimPrefix(key, "/")) |
| 282 | r.setWriteOptions(q) |
| 283 | for param, val := range params { |
| 284 | r.params.Set(param, val) |
| 285 | } |
| 286 | rtt, resp, err := requireOK(k.c.doRequest(r)) |
| 287 | if err != nil { |
| 288 | return false, nil, err |
| 289 | } |
| 290 | defer resp.Body.Close() |
| 291 | |
| 292 | qm := &WriteMeta{} |
| 293 | qm.RequestTime = rtt |
| 294 | |
| 295 | var buf bytes.Buffer |
| 296 | if _, err := io.Copy(&buf, resp.Body); err != nil { |
| 297 | return false, nil, fmt.Errorf("Failed to read response: %v", err) |
| 298 | } |
| 299 | res := strings.Contains(buf.String(), "true") |
| 300 | return res, qm, nil |
| 301 | } |
| 302 | |
| 303 | // TxnOp is the internal format we send to Consul. It's not specific to KV, |
| 304 | // though currently only KV operations are supported. |
| 305 | type TxnOp struct { |
| 306 | KV *KVTxnOp |
| 307 | } |
| 308 | |
| 309 | // TxnOps is a list of transaction operations. |
| 310 | type TxnOps []*TxnOp |
| 311 | |
| 312 | // TxnResult is the internal format we receive from Consul. |
| 313 | type TxnResult struct { |
| 314 | KV *KVPair |
| 315 | } |
| 316 | |
| 317 | // TxnResults is a list of TxnResult objects. |
| 318 | type TxnResults []*TxnResult |
| 319 | |
| 320 | // TxnError is used to return information about an operation in a transaction. |
| 321 | type TxnError struct { |
| 322 | OpIndex int |
| 323 | What string |
| 324 | } |
| 325 | |
| 326 | // TxnErrors is a list of TxnError objects. |
| 327 | type TxnErrors []*TxnError |
| 328 | |
| 329 | // TxnResponse is the internal format we receive from Consul. |
| 330 | type TxnResponse struct { |
| 331 | Results TxnResults |
| 332 | Errors TxnErrors |
| 333 | } |
| 334 | |
| 335 | // Txn is used to apply multiple KV operations in a single, atomic transaction. |
| 336 | // |
| 337 | // Note that Go will perform the required base64 encoding on the values |
| 338 | // automatically because the type is a byte slice. Transactions are defined as a |
| 339 | // list of operations to perform, using the KVOp constants and KVTxnOp structure |
| 340 | // to define operations. If any operation fails, none of the changes are applied |
| 341 | // to the state store. Note that this hides the internal raw transaction interface |
| 342 | // and munges the input and output types into KV-specific ones for ease of use. |
| 343 | // If there are more non-KV operations in the future we may break out a new |
| 344 | // transaction API client, but it will be easy to keep this KV-specific variant |
| 345 | // supported. |
| 346 | // |
| 347 | // Even though this is generally a write operation, we take a QueryOptions input |
| 348 | // and return a QueryMeta output. If the transaction contains only read ops, then |
| 349 | // Consul will fast-path it to a different endpoint internally which supports |
| 350 | // consistency controls, but not blocking. If there are write operations then |
| 351 | // the request will always be routed through raft and any consistency settings |
| 352 | // will be ignored. |
| 353 | // |
| 354 | // Here's an example: |
| 355 | // |
| 356 | // ops := KVTxnOps{ |
| 357 | // &KVTxnOp{ |
| 358 | // Verb: KVLock, |
| 359 | // Key: "test/lock", |
| 360 | // Session: "adf4238a-882b-9ddc-4a9d-5b6758e4159e", |
| 361 | // Value: []byte("hello"), |
| 362 | // }, |
| 363 | // &KVTxnOp{ |
| 364 | // Verb: KVGet, |
| 365 | // Key: "another/key", |
| 366 | // }, |
| 367 | // } |
| 368 | // ok, response, _, err := kv.Txn(&ops, nil) |
| 369 | // |
| 370 | // If there is a problem making the transaction request then an error will be |
| 371 | // returned. Otherwise, the ok value will be true if the transaction succeeded |
| 372 | // or false if it was rolled back. The response is a structured return value which |
| 373 | // will have the outcome of the transaction. Its Results member will have entries |
| 374 | // for each operation. Deleted keys will have a nil entry in the, and to save |
| 375 | // space, the Value of each key in the Results will be nil unless the operation |
| 376 | // is a KVGet. If the transaction was rolled back, the Errors member will have |
| 377 | // entries referencing the index of the operation that failed along with an error |
| 378 | // message. |
| 379 | func (k *KV) Txn(txn KVTxnOps, q *QueryOptions) (bool, *KVTxnResponse, *QueryMeta, error) { |
| 380 | r := k.c.newRequest("PUT", "/v1/txn") |
| 381 | r.setQueryOptions(q) |
| 382 | |
| 383 | // Convert into the internal format since this is an all-KV txn. |
| 384 | ops := make(TxnOps, 0, len(txn)) |
| 385 | for _, kvOp := range txn { |
| 386 | ops = append(ops, &TxnOp{KV: kvOp}) |
| 387 | } |
| 388 | r.obj = ops |
| 389 | rtt, resp, err := k.c.doRequest(r) |
| 390 | if err != nil { |
| 391 | return false, nil, nil, err |
| 392 | } |
| 393 | defer resp.Body.Close() |
| 394 | |
| 395 | qm := &QueryMeta{} |
| 396 | parseQueryMeta(resp, qm) |
| 397 | qm.RequestTime = rtt |
| 398 | |
| 399 | if resp.StatusCode == http.StatusOK || resp.StatusCode == http.StatusConflict { |
| 400 | var txnResp TxnResponse |
| 401 | if err := decodeBody(resp, &txnResp); err != nil { |
| 402 | return false, nil, nil, err |
| 403 | } |
| 404 | |
| 405 | // Convert from the internal format. |
| 406 | kvResp := KVTxnResponse{ |
| 407 | Errors: txnResp.Errors, |
| 408 | } |
| 409 | for _, result := range txnResp.Results { |
| 410 | kvResp.Results = append(kvResp.Results, result.KV) |
| 411 | } |
| 412 | return resp.StatusCode == http.StatusOK, &kvResp, qm, nil |
| 413 | } |
| 414 | |
| 415 | var buf bytes.Buffer |
| 416 | if _, err := io.Copy(&buf, resp.Body); err != nil { |
| 417 | return false, nil, nil, fmt.Errorf("Failed to read response: %v", err) |
| 418 | } |
| 419 | return false, nil, nil, fmt.Errorf("Failed request: %s", buf.String()) |
| 420 | } |