diff options
author | Unknwon <u@gogs.io> | 2017-02-09 19:48:13 -0500 |
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committer | Unknwon <u@gogs.io> | 2017-02-09 19:48:13 -0500 |
commit | 2fd69f13d9599a6c58b47225565163fd7d87889f (patch) | |
tree | fd19e868e1c2e95a5fb83a268f6e393669d6ee79 /vendor/github.com/bradfitz/gomemcache/memcache/memcache.go | |
parent | eb66060cd7b9bce996b1d75ae80ce1ef31d5ce62 (diff) |
vendor: check in vendors
Bye bye glide...
Diffstat (limited to 'vendor/github.com/bradfitz/gomemcache/memcache/memcache.go')
-rw-r--r-- | vendor/github.com/bradfitz/gomemcache/memcache/memcache.go | 666 |
1 files changed, 666 insertions, 0 deletions
diff --git a/vendor/github.com/bradfitz/gomemcache/memcache/memcache.go b/vendor/github.com/bradfitz/gomemcache/memcache/memcache.go new file mode 100644 index 00000000..7b5442d7 --- /dev/null +++ b/vendor/github.com/bradfitz/gomemcache/memcache/memcache.go @@ -0,0 +1,666 @@ +/* +Copyright 2011 Google Inc. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +// Package memcache provides a client for the memcached cache server. +package memcache + +import ( + "bufio" + "bytes" + "errors" + "fmt" + "io" + "io/ioutil" + "net" + + "strconv" + "strings" + "sync" + "time" +) + +// Similar to: +// http://code.google.com/appengine/docs/go/memcache/reference.html + +var ( + // ErrCacheMiss means that a Get failed because the item wasn't present. + ErrCacheMiss = errors.New("memcache: cache miss") + + // ErrCASConflict means that a CompareAndSwap call failed due to the + // cached value being modified between the Get and the CompareAndSwap. + // If the cached value was simply evicted rather than replaced, + // ErrNotStored will be returned instead. + ErrCASConflict = errors.New("memcache: compare-and-swap conflict") + + // ErrNotStored means that a conditional write operation (i.e. Add or + // CompareAndSwap) failed because the condition was not satisfied. + ErrNotStored = errors.New("memcache: item not stored") + + // ErrServer means that a server error occurred. + ErrServerError = errors.New("memcache: server error") + + // ErrNoStats means that no statistics were available. + ErrNoStats = errors.New("memcache: no statistics available") + + // ErrMalformedKey is returned when an invalid key is used. + // Keys must be at maximum 250 bytes long, ASCII, and not + // contain whitespace or control characters. + ErrMalformedKey = errors.New("malformed: key is too long or contains invalid characters") + + // ErrNoServers is returned when no servers are configured or available. + ErrNoServers = errors.New("memcache: no servers configured or available") +) + +// DefaultTimeout is the default socket read/write timeout. +const DefaultTimeout = 100 * time.Millisecond + +const ( + buffered = 8 // arbitrary buffered channel size, for readability + maxIdleConnsPerAddr = 2 // TODO(bradfitz): make this configurable? +) + +// resumableError returns true if err is only a protocol-level cache error. +// This is used to determine whether or not a server connection should +// be re-used or not. If an error occurs, by default we don't reuse the +// connection, unless it was just a cache error. +func resumableError(err error) bool { + switch err { + case ErrCacheMiss, ErrCASConflict, ErrNotStored, ErrMalformedKey: + return true + } + return false +} + +func legalKey(key string) bool { + if len(key) > 250 { + return false + } + for i := 0; i < len(key); i++ { + if key[i] <= ' ' || key[i] > 0x7e { + return false + } + } + return true +} + +var ( + crlf = []byte("\r\n") + space = []byte(" ") + resultOK = []byte("OK\r\n") + resultStored = []byte("STORED\r\n") + resultNotStored = []byte("NOT_STORED\r\n") + resultExists = []byte("EXISTS\r\n") + resultNotFound = []byte("NOT_FOUND\r\n") + resultDeleted = []byte("DELETED\r\n") + resultEnd = []byte("END\r\n") + resultOk = []byte("OK\r\n") + resultTouched = []byte("TOUCHED\r\n") + + resultClientErrorPrefix = []byte("CLIENT_ERROR ") +) + +// New returns a memcache client using the provided server(s) +// with equal weight. If a server is listed multiple times, +// it gets a proportional amount of weight. +func New(server ...string) *Client { + ss := new(ServerList) + ss.SetServers(server...) + return NewFromSelector(ss) +} + +// NewFromSelector returns a new Client using the provided ServerSelector. +func NewFromSelector(ss ServerSelector) *Client { + return &Client{selector: ss} +} + +// Client is a memcache client. +// It is safe for unlocked use by multiple concurrent goroutines. +type Client struct { + // Timeout specifies the socket read/write timeout. + // If zero, DefaultTimeout is used. + Timeout time.Duration + + selector ServerSelector + + lk sync.Mutex + freeconn map[string][]*conn +} + +// Item is an item to be got or stored in a memcached server. +type Item struct { + // Key is the Item's key (250 bytes maximum). + Key string + + // Value is the Item's value. + Value []byte + + // Flags are server-opaque flags whose semantics are entirely + // up to the app. + Flags uint32 + + // Expiration is the cache expiration time, in seconds: either a relative + // time from now (up to 1 month), or an absolute Unix epoch time. + // Zero means the Item has no expiration time. + Expiration int32 + + // Compare and swap ID. + casid uint64 +} + +// conn is a connection to a server. +type conn struct { + nc net.Conn + rw *bufio.ReadWriter + addr net.Addr + c *Client +} + +// release returns this connection back to the client's free pool +func (cn *conn) release() { + cn.c.putFreeConn(cn.addr, cn) +} + +func (cn *conn) extendDeadline() { + cn.nc.SetDeadline(time.Now().Add(cn.c.netTimeout())) +} + +// condRelease releases this connection if the error pointed to by err +// is nil (not an error) or is only a protocol level error (e.g. a +// cache miss). The purpose is to not recycle TCP connections that +// are bad. +func (cn *conn) condRelease(err *error) { + if *err == nil || resumableError(*err) { + cn.release() + } else { + cn.nc.Close() + } +} + +func (c *Client) putFreeConn(addr net.Addr, cn *conn) { + c.lk.Lock() + defer c.lk.Unlock() + if c.freeconn == nil { + c.freeconn = make(map[string][]*conn) + } + freelist := c.freeconn[addr.String()] + if len(freelist) >= maxIdleConnsPerAddr { + cn.nc.Close() + return + } + c.freeconn[addr.String()] = append(freelist, cn) +} + +func (c *Client) getFreeConn(addr net.Addr) (cn *conn, ok bool) { + c.lk.Lock() + defer c.lk.Unlock() + if c.freeconn == nil { + return nil, false + } + freelist, ok := c.freeconn[addr.String()] + if !ok || len(freelist) == 0 { + return nil, false + } + cn = freelist[len(freelist)-1] + c.freeconn[addr.String()] = freelist[:len(freelist)-1] + return cn, true +} + +func (c *Client) netTimeout() time.Duration { + if c.Timeout != 0 { + return c.Timeout + } + return DefaultTimeout +} + +// ConnectTimeoutError is the error type used when it takes +// too long to connect to the desired host. This level of +// detail can generally be ignored. +type ConnectTimeoutError struct { + Addr net.Addr +} + +func (cte *ConnectTimeoutError) Error() string { + return "memcache: connect timeout to " + cte.Addr.String() +} + +func (c *Client) dial(addr net.Addr) (net.Conn, error) { + type connError struct { + cn net.Conn + err error + } + + nc, err := net.DialTimeout(addr.Network(), addr.String(), c.netTimeout()) + if err == nil { + return nc, nil + } + + if ne, ok := err.(net.Error); ok && ne.Timeout() { + return nil, &ConnectTimeoutError{addr} + } + + return nil, err +} + +func (c *Client) getConn(addr net.Addr) (*conn, error) { + cn, ok := c.getFreeConn(addr) + if ok { + cn.extendDeadline() + return cn, nil + } + nc, err := c.dial(addr) + if err != nil { + return nil, err + } + cn = &conn{ + nc: nc, + addr: addr, + rw: bufio.NewReadWriter(bufio.NewReader(nc), bufio.NewWriter(nc)), + c: c, + } + cn.extendDeadline() + return cn, nil +} + +func (c *Client) onItem(item *Item, fn func(*Client, *bufio.ReadWriter, *Item) error) error { + addr, err := c.selector.PickServer(item.Key) + if err != nil { + return err + } + cn, err := c.getConn(addr) + if err != nil { + return err + } + defer cn.condRelease(&err) + if err = fn(c, cn.rw, item); err != nil { + return err + } + return nil +} + +func (c *Client) FlushAll() error { + return c.selector.Each(c.flushAllFromAddr) +} + +// Get gets the item for the given key. ErrCacheMiss is returned for a +// memcache cache miss. The key must be at most 250 bytes in length. +func (c *Client) Get(key string) (item *Item, err error) { + err = c.withKeyAddr(key, func(addr net.Addr) error { + return c.getFromAddr(addr, []string{key}, func(it *Item) { item = it }) + }) + if err == nil && item == nil { + err = ErrCacheMiss + } + return +} + +// Touch updates the expiry for the given key. The seconds parameter is either +// a Unix timestamp or, if seconds is less than 1 month, the number of seconds +// into the future at which time the item will expire. ErrCacheMiss is returned if the +// key is not in the cache. The key must be at most 250 bytes in length. +func (c *Client) Touch(key string, seconds int32) (err error) { + return c.withKeyAddr(key, func(addr net.Addr) error { + return c.touchFromAddr(addr, []string{key}, seconds) + }) +} + +func (c *Client) withKeyAddr(key string, fn func(net.Addr) error) (err error) { + if !legalKey(key) { + return ErrMalformedKey + } + addr, err := c.selector.PickServer(key) + if err != nil { + return err + } + return fn(addr) +} + +func (c *Client) withAddrRw(addr net.Addr, fn func(*bufio.ReadWriter) error) (err error) { + cn, err := c.getConn(addr) + if err != nil { + return err + } + defer cn.condRelease(&err) + return fn(cn.rw) +} + +func (c *Client) withKeyRw(key string, fn func(*bufio.ReadWriter) error) error { + return c.withKeyAddr(key, func(addr net.Addr) error { + return c.withAddrRw(addr, fn) + }) +} + +func (c *Client) getFromAddr(addr net.Addr, keys []string, cb func(*Item)) error { + return c.withAddrRw(addr, func(rw *bufio.ReadWriter) error { + if _, err := fmt.Fprintf(rw, "gets %s\r\n", strings.Join(keys, " ")); err != nil { + return err + } + if err := rw.Flush(); err != nil { + return err + } + if err := parseGetResponse(rw.Reader, cb); err != nil { + return err + } + return nil + }) +} + +// flushAllFromAddr send the flush_all command to the given addr +func (c *Client) flushAllFromAddr(addr net.Addr) error { + return c.withAddrRw(addr, func(rw *bufio.ReadWriter) error { + if _, err := fmt.Fprintf(rw, "flush_all\r\n"); err != nil { + return err + } + if err := rw.Flush(); err != nil { + return err + } + line, err := rw.ReadSlice('\n') + if err != nil { + return err + } + switch { + case bytes.Equal(line, resultOk): + break + default: + return fmt.Errorf("memcache: unexpected response line from flush_all: %q", string(line)) + } + return nil + }) +} + +func (c *Client) touchFromAddr(addr net.Addr, keys []string, expiration int32) error { + return c.withAddrRw(addr, func(rw *bufio.ReadWriter) error { + for _, key := range keys { + if _, err := fmt.Fprintf(rw, "touch %s %d\r\n", key, expiration); err != nil { + return err + } + if err := rw.Flush(); err != nil { + return err + } + line, err := rw.ReadSlice('\n') + if err != nil { + return err + } + switch { + case bytes.Equal(line, resultTouched): + break + case bytes.Equal(line, resultNotFound): + return ErrCacheMiss + default: + return fmt.Errorf("memcache: unexpected response line from touch: %q", string(line)) + } + } + return nil + }) +} + +// GetMulti is a batch version of Get. The returned map from keys to +// items may have fewer elements than the input slice, due to memcache +// cache misses. Each key must be at most 250 bytes in length. +// If no error is returned, the returned map will also be non-nil. +func (c *Client) GetMulti(keys []string) (map[string]*Item, error) { + var lk sync.Mutex + m := make(map[string]*Item) + addItemToMap := func(it *Item) { + lk.Lock() + defer lk.Unlock() + m[it.Key] = it + } + + keyMap := make(map[net.Addr][]string) + for _, key := range keys { + if !legalKey(key) { + return nil, ErrMalformedKey + } + addr, err := c.selector.PickServer(key) + if err != nil { + return nil, err + } + keyMap[addr] = append(keyMap[addr], key) + } + + ch := make(chan error, buffered) + for addr, keys := range keyMap { + go func(addr net.Addr, keys []string) { + ch <- c.getFromAddr(addr, keys, addItemToMap) + }(addr, keys) + } + + var err error + for _ = range keyMap { + if ge := <-ch; ge != nil { + err = ge + } + } + return m, err +} + +// parseGetResponse reads a GET response from r and calls cb for each +// read and allocated Item +func parseGetResponse(r *bufio.Reader, cb func(*Item)) error { + for { + line, err := r.ReadSlice('\n') + if err != nil { + return err + } + if bytes.Equal(line, resultEnd) { + return nil + } + it := new(Item) + size, err := scanGetResponseLine(line, it) + if err != nil { + return err + } + it.Value, err = ioutil.ReadAll(io.LimitReader(r, int64(size)+2)) + if err != nil { + return err + } + if !bytes.HasSuffix(it.Value, crlf) { + return fmt.Errorf("memcache: corrupt get result read") + } + it.Value = it.Value[:size] + cb(it) + } +} + +// scanGetResponseLine populates it and returns the declared size of the item. +// It does not read the bytes of the item. +func scanGetResponseLine(line []byte, it *Item) (size int, err error) { + pattern := "VALUE %s %d %d %d\r\n" + dest := []interface{}{&it.Key, &it.Flags, &size, &it.casid} + if bytes.Count(line, space) == 3 { + pattern = "VALUE %s %d %d\r\n" + dest = dest[:3] + } + n, err := fmt.Sscanf(string(line), pattern, dest...) + if err != nil || n != len(dest) { + return -1, fmt.Errorf("memcache: unexpected line in get response: %q", line) + } + return size, nil +} + +// Set writes the given item, unconditionally. +func (c *Client) Set(item *Item) error { + return c.onItem(item, (*Client).set) +} + +func (c *Client) set(rw *bufio.ReadWriter, item *Item) error { + return c.populateOne(rw, "set", item) +} + +// Add writes the given item, if no value already exists for its +// key. ErrNotStored is returned if that condition is not met. +func (c *Client) Add(item *Item) error { + return c.onItem(item, (*Client).add) +} + +func (c *Client) add(rw *bufio.ReadWriter, item *Item) error { + return c.populateOne(rw, "add", item) +} + +// Replace writes the given item, but only if the server *does* +// already hold data for this key +func (c *Client) Replace(item *Item) error { + return c.onItem(item, (*Client).replace) +} + +func (c *Client) replace(rw *bufio.ReadWriter, item *Item) error { + return c.populateOne(rw, "replace", item) +} + +// CompareAndSwap writes the given item that was previously returned +// by Get, if the value was neither modified or evicted between the +// Get and the CompareAndSwap calls. The item's Key should not change +// between calls but all other item fields may differ. ErrCASConflict +// is returned if the value was modified in between the +// calls. ErrNotStored is returned if the value was evicted in between +// the calls. +func (c *Client) CompareAndSwap(item *Item) error { + return c.onItem(item, (*Client).cas) +} + +func (c *Client) cas(rw *bufio.ReadWriter, item *Item) error { + return c.populateOne(rw, "cas", item) +} + +func (c *Client) populateOne(rw *bufio.ReadWriter, verb string, item *Item) error { + if !legalKey(item.Key) { + return ErrMalformedKey + } + var err error + if verb == "cas" { + _, err = fmt.Fprintf(rw, "%s %s %d %d %d %d\r\n", + verb, item.Key, item.Flags, item.Expiration, len(item.Value), item.casid) + } else { + _, err = fmt.Fprintf(rw, "%s %s %d %d %d\r\n", + verb, item.Key, item.Flags, item.Expiration, len(item.Value)) + } + if err != nil { + return err + } + if _, err = rw.Write(item.Value); err != nil { + return err + } + if _, err := rw.Write(crlf); err != nil { + return err + } + if err := rw.Flush(); err != nil { + return err + } + line, err := rw.ReadSlice('\n') + if err != nil { + return err + } + switch { + case bytes.Equal(line, resultStored): + return nil + case bytes.Equal(line, resultNotStored): + return ErrNotStored + case bytes.Equal(line, resultExists): + return ErrCASConflict + case bytes.Equal(line, resultNotFound): + return ErrCacheMiss + } + return fmt.Errorf("memcache: unexpected response line from %q: %q", verb, string(line)) +} + +func writeReadLine(rw *bufio.ReadWriter, format string, args ...interface{}) ([]byte, error) { + _, err := fmt.Fprintf(rw, format, args...) + if err != nil { + return nil, err + } + if err := rw.Flush(); err != nil { + return nil, err + } + line, err := rw.ReadSlice('\n') + return line, err +} + +func writeExpectf(rw *bufio.ReadWriter, expect []byte, format string, args ...interface{}) error { + line, err := writeReadLine(rw, format, args...) + if err != nil { + return err + } + switch { + case bytes.Equal(line, resultOK): + return nil + case bytes.Equal(line, expect): + return nil + case bytes.Equal(line, resultNotStored): + return ErrNotStored + case bytes.Equal(line, resultExists): + return ErrCASConflict + case bytes.Equal(line, resultNotFound): + return ErrCacheMiss + } + return fmt.Errorf("memcache: unexpected response line: %q", string(line)) +} + +// Delete deletes the item with the provided key. The error ErrCacheMiss is +// returned if the item didn't already exist in the cache. +func (c *Client) Delete(key string) error { + return c.withKeyRw(key, func(rw *bufio.ReadWriter) error { + return writeExpectf(rw, resultDeleted, "delete %s\r\n", key) + }) +} + +// DeleteAll deletes all items in the cache. +func (c *Client) DeleteAll() error { + return c.withKeyRw("", func(rw *bufio.ReadWriter) error { + return writeExpectf(rw, resultDeleted, "flush_all\r\n") + }) +} + +// Increment atomically increments key by delta. The return value is +// the new value after being incremented or an error. If the value +// didn't exist in memcached the error is ErrCacheMiss. The value in +// memcached must be an decimal number, or an error will be returned. +// On 64-bit overflow, the new value wraps around. +func (c *Client) Increment(key string, delta uint64) (newValue uint64, err error) { + return c.incrDecr("incr", key, delta) +} + +// Decrement atomically decrements key by delta. The return value is +// the new value after being decremented or an error. If the value +// didn't exist in memcached the error is ErrCacheMiss. The value in +// memcached must be an decimal number, or an error will be returned. +// On underflow, the new value is capped at zero and does not wrap +// around. +func (c *Client) Decrement(key string, delta uint64) (newValue uint64, err error) { + return c.incrDecr("decr", key, delta) +} + +func (c *Client) incrDecr(verb, key string, delta uint64) (uint64, error) { + var val uint64 + err := c.withKeyRw(key, func(rw *bufio.ReadWriter) error { + line, err := writeReadLine(rw, "%s %s %d\r\n", verb, key, delta) + if err != nil { + return err + } + switch { + case bytes.Equal(line, resultNotFound): + return ErrCacheMiss + case bytes.HasPrefix(line, resultClientErrorPrefix): + errMsg := line[len(resultClientErrorPrefix) : len(line)-2] + return errors.New("memcache: client error: " + string(errMsg)) + } + val, err = strconv.ParseUint(string(line[:len(line)-2]), 10, 64) + if err != nil { + return err + } + return nil + }) + return val, err +} |