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Diffstat (limited to 'src/dma/vendor/github.com/streadway/amqp/types.go')
| -rw-r--r-- | src/dma/vendor/github.com/streadway/amqp/types.go | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/src/dma/vendor/github.com/streadway/amqp/types.go b/src/dma/vendor/github.com/streadway/amqp/types.go new file mode 100644 index 00000000..d3ece707 --- /dev/null +++ b/src/dma/vendor/github.com/streadway/amqp/types.go @@ -0,0 +1,428 @@ +// Copyright (c) 2012, Sean Treadway, SoundCloud Ltd. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. +// Source code and contact info at http://github.com/streadway/amqp + +package amqp + +import ( + "fmt" + "io" + "time" +) + +// Constants for standard AMQP 0-9-1 exchange types. +const ( + ExchangeDirect = "direct" + ExchangeFanout = "fanout" + ExchangeTopic = "topic" + ExchangeHeaders = "headers" +) + +var ( + // ErrClosed is returned when the channel or connection is not open + ErrClosed = &Error{Code: ChannelError, Reason: "channel/connection is not open"} + + // ErrChannelMax is returned when Connection.Channel has been called enough + // times that all channel IDs have been exhausted in the client or the + // server. + ErrChannelMax = &Error{Code: ChannelError, Reason: "channel id space exhausted"} + + // ErrSASL is returned from Dial when the authentication mechanism could not + // be negoated. + ErrSASL = &Error{Code: AccessRefused, Reason: "SASL could not negotiate a shared mechanism"} + + // ErrCredentials is returned when the authenticated client is not authorized + // to any vhost. + ErrCredentials = &Error{Code: AccessRefused, Reason: "username or password not allowed"} + + // ErrVhost is returned when the authenticated user is not permitted to + // access the requested Vhost. + ErrVhost = &Error{Code: AccessRefused, Reason: "no access to this vhost"} + + // ErrSyntax is hard protocol error, indicating an unsupported protocol, + // implementation or encoding. + ErrSyntax = &Error{Code: SyntaxError, Reason: "invalid field or value inside of a frame"} + + // ErrFrame is returned when the protocol frame cannot be read from the + // server, indicating an unsupported protocol or unsupported frame type. + ErrFrame = &Error{Code: FrameError, Reason: "frame could not be parsed"} + + // ErrCommandInvalid is returned when the server sends an unexpected response + // to this requested message type. This indicates a bug in this client. + ErrCommandInvalid = &Error{Code: CommandInvalid, Reason: "unexpected command received"} + + // ErrUnexpectedFrame is returned when something other than a method or + // heartbeat frame is delivered to the Connection, indicating a bug in the + // client. + ErrUnexpectedFrame = &Error{Code: UnexpectedFrame, Reason: "unexpected frame received"} + + // ErrFieldType is returned when writing a message containing a Go type unsupported by AMQP. + ErrFieldType = &Error{Code: SyntaxError, Reason: "unsupported table field type"} +) + +// Error captures the code and reason a channel or connection has been closed +// by the server. +type Error struct { + Code int // constant code from the specification + Reason string // description of the error + Server bool // true when initiated from the server, false when from this library + Recover bool // true when this error can be recovered by retrying later or with different parameters +} + +func newError(code uint16, text string) *Error { + return &Error{ + Code: int(code), + Reason: text, + Recover: isSoftExceptionCode(int(code)), + Server: true, + } +} + +func (e Error) Error() string { + return fmt.Sprintf("Exception (%d) Reason: %q", e.Code, e.Reason) +} + +// Used by header frames to capture routing and header information +type properties struct { + ContentType string // MIME content type + ContentEncoding string // MIME content encoding + Headers Table // Application or header exchange table + DeliveryMode uint8 // queue implementation use - Transient (1) or Persistent (2) + Priority uint8 // queue implementation use - 0 to 9 + CorrelationId string // application use - correlation identifier + ReplyTo string // application use - address to to reply to (ex: RPC) + Expiration string // implementation use - message expiration spec + MessageId string // application use - message identifier + Timestamp time.Time // application use - message timestamp + Type string // application use - message type name + UserId string // application use - creating user id + AppId string // application use - creating application + reserved1 string // was cluster-id - process for buffer consumption +} + +// DeliveryMode. Transient means higher throughput but messages will not be +// restored on broker restart. The delivery mode of publishings is unrelated +// to the durability of the queues they reside on. Transient messages will +// not be restored to durable queues, persistent messages will be restored to +// durable queues and lost on non-durable queues during server restart. +// +// This remains typed as uint8 to match Publishing.DeliveryMode. Other +// delivery modes specific to custom queue implementations are not enumerated +// here. +const ( + Transient uint8 = 1 + Persistent uint8 = 2 +) + +// The property flags are an array of bits that indicate the presence or +// absence of each property value in sequence. The bits are ordered from most +// high to low - bit 15 indicates the first property. +const ( + flagContentType = 0x8000 + flagContentEncoding = 0x4000 + flagHeaders = 0x2000 + flagDeliveryMode = 0x1000 + flagPriority = 0x0800 + flagCorrelationId = 0x0400 + flagReplyTo = 0x0200 + flagExpiration = 0x0100 + flagMessageId = 0x0080 + flagTimestamp = 0x0040 + flagType = 0x0020 + flagUserId = 0x0010 + flagAppId = 0x0008 + flagReserved1 = 0x0004 +) + +// Queue captures the current server state of the queue on the server returned +// from Channel.QueueDeclare or Channel.QueueInspect. +type Queue struct { + Name string // server confirmed or generated name + Messages int // count of messages not awaiting acknowledgment + Consumers int // number of consumers receiving deliveries +} + +// Publishing captures the client message sent to the server. The fields +// outside of the Headers table included in this struct mirror the underlying +// fields in the content frame. They use native types for convenience and +// efficiency. +type Publishing struct { + // Application or exchange specific fields, + // the headers exchange will inspect this field. + Headers Table + + // Properties + ContentType string // MIME content type + ContentEncoding string // MIME content encoding + DeliveryMode uint8 // Transient (0 or 1) or Persistent (2) + Priority uint8 // 0 to 9 + CorrelationId string // correlation identifier + ReplyTo string // address to to reply to (ex: RPC) + Expiration string // message expiration spec + MessageId string // message identifier + Timestamp time.Time // message timestamp + Type string // message type name + UserId string // creating user id - ex: "guest" + AppId string // creating application id + + // The application specific payload of the message + Body []byte +} + +// Blocking notifies the server's TCP flow control of the Connection. When a +// server hits a memory or disk alarm it will block all connections until the +// resources are reclaimed. Use NotifyBlock on the Connection to receive these +// events. +type Blocking struct { + Active bool // TCP pushback active/inactive on server + Reason string // Server reason for activation +} + +// Confirmation notifies the acknowledgment or negative acknowledgement of a +// publishing identified by its delivery tag. Use NotifyPublish on the Channel +// to consume these events. +type Confirmation struct { + DeliveryTag uint64 // A 1 based counter of publishings from when the channel was put in Confirm mode + Ack bool // True when the server successfully received the publishing +} + +// Decimal matches the AMQP decimal type. Scale is the number of decimal +// digits Scale == 2, Value == 12345, Decimal == 123.45 +type Decimal struct { + Scale uint8 + Value int32 +} + +// Table stores user supplied fields of the following types: +// +// bool +// byte +// float32 +// float64 +// int +// int16 +// int32 +// int64 +// nil +// string +// time.Time +// amqp.Decimal +// amqp.Table +// []byte +// []interface{} - containing above types +// +// Functions taking a table will immediately fail when the table contains a +// value of an unsupported type. +// +// The caller must be specific in which precision of integer it wishes to +// encode. +// +// Use a type assertion when reading values from a table for type conversion. +// +// RabbitMQ expects int32 for integer values. +// +type Table map[string]interface{} + +func validateField(f interface{}) error { + switch fv := f.(type) { + case nil, bool, byte, int, int16, int32, int64, float32, float64, string, []byte, Decimal, time.Time: + return nil + + case []interface{}: + for _, v := range fv { + if err := validateField(v); err != nil { + return fmt.Errorf("in array %s", err) + } + } + return nil + + case Table: + for k, v := range fv { + if err := validateField(v); err != nil { + return fmt.Errorf("table field %q %s", k, err) + } + } + return nil + } + + return fmt.Errorf("value %t not supported", f) +} + +// Validate returns and error if any Go types in the table are incompatible with AMQP types. +func (t Table) Validate() error { + return validateField(t) +} + +// Heap interface for maintaining delivery tags +type tagSet []uint64 + +func (set tagSet) Len() int { return len(set) } +func (set tagSet) Less(i, j int) bool { return (set)[i] < (set)[j] } +func (set tagSet) Swap(i, j int) { (set)[i], (set)[j] = (set)[j], (set)[i] } +func (set *tagSet) Push(tag interface{}) { *set = append(*set, tag.(uint64)) } +func (set *tagSet) Pop() interface{} { + val := (*set)[len(*set)-1] + *set = (*set)[:len(*set)-1] + return val +} + +type message interface { + id() (uint16, uint16) + wait() bool + read(io.Reader) error + write(io.Writer) error +} + +type messageWithContent interface { + message + getContent() (properties, []byte) + setContent(properties, []byte) +} + +/* +The base interface implemented as: + +2.3.5 frame Details + +All frames consist of a header (7 octets), a payload of arbitrary size, and a 'frame-end' octet that detects +malformed frames: + + 0 1 3 7 size+7 size+8 + +------+---------+-------------+ +------------+ +-----------+ + | type | channel | size | | payload | | frame-end | + +------+---------+-------------+ +------------+ +-----------+ + octet short long size octets octet + +To read a frame, we: + + 1. Read the header and check the frame type and channel. + 2. Depending on the frame type, we read the payload and process it. + 3. Read the frame end octet. + +In realistic implementations where performance is a concern, we would use +“read-ahead buffering” or “gathering reads” to avoid doing three separate +system calls to read a frame. + +*/ +type frame interface { + write(io.Writer) error + channel() uint16 +} + +type reader struct { + r io.Reader +} + +type writer struct { + w io.Writer +} + +// Implements the frame interface for Connection RPC +type protocolHeader struct{} + +func (protocolHeader) write(w io.Writer) error { + _, err := w.Write([]byte{'A', 'M', 'Q', 'P', 0, 0, 9, 1}) + return err +} + +func (protocolHeader) channel() uint16 { + panic("only valid as initial handshake") +} + +/* +Method frames carry the high-level protocol commands (which we call "methods"). +One method frame carries one command. The method frame payload has this format: + + 0 2 4 + +----------+-----------+-------------- - - + | class-id | method-id | arguments... + +----------+-----------+-------------- - - + short short ... + +To process a method frame, we: + 1. Read the method frame payload. + 2. Unpack it into a structure. A given method always has the same structure, + so we can unpack the method rapidly. 3. Check that the method is allowed in + the current context. + 4. Check that the method arguments are valid. + 5. Execute the method. + +Method frame bodies are constructed as a list of AMQP data fields (bits, +integers, strings and string tables). The marshalling code is trivially +generated directly from the protocol specifications, and can be very rapid. +*/ +type methodFrame struct { + ChannelId uint16 + ClassId uint16 + MethodId uint16 + Method message +} + +func (f *methodFrame) channel() uint16 { return f.ChannelId } + +/* +Heartbeating is a technique designed to undo one of TCP/IP's features, namely +its ability to recover from a broken physical connection by closing only after +a quite long time-out. In some scenarios we need to know very rapidly if a +peer is disconnected or not responding for other reasons (e.g. it is looping). +Since heartbeating can be done at a low level, we implement this as a special +type of frame that peers exchange at the transport level, rather than as a +class method. +*/ +type heartbeatFrame struct { + ChannelId uint16 +} + +func (f *heartbeatFrame) channel() uint16 { return f.ChannelId } + +/* +Certain methods (such as Basic.Publish, Basic.Deliver, etc.) are formally +defined as carrying content. When a peer sends such a method frame, it always +follows it with a content header and zero or more content body frames. + +A content header frame has this format: + + 0 2 4 12 14 + +----------+--------+-----------+----------------+------------- - - + | class-id | weight | body size | property flags | property list... + +----------+--------+-----------+----------------+------------- - - + short short long long short remainder... + +We place content body in distinct frames (rather than including it in the +method) so that AMQP may support "zero copy" techniques in which content is +never marshalled or encoded. We place the content properties in their own +frame so that recipients can selectively discard contents they do not want to +process +*/ +type headerFrame struct { + ChannelId uint16 + ClassId uint16 + weight uint16 + Size uint64 + Properties properties +} + +func (f *headerFrame) channel() uint16 { return f.ChannelId } + +/* +Content is the application data we carry from client-to-client via the AMQP +server. Content is, roughly speaking, a set of properties plus a binary data +part. The set of allowed properties are defined by the Basic class, and these +form the "content header frame". The data can be any size, and MAY be broken +into several (or many) chunks, each forming a "content body frame". + +Looking at the frames for a specific channel, as they pass on the wire, we +might see something like this: + + [method] + [method] [header] [body] [body] + [method] + ... +*/ +type bodyFrame struct { + ChannelId uint16 + Body []byte +} + +func (f *bodyFrame) channel() uint16 { return f.ChannelId } |