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| 1 | +// SPDX-License-Identifier: PMPL-1.0-or-later |
| 2 | +// V-Ecosystem AMQP Protocol Connector |
| 3 | +// Author: Jonathan D.A. Jewell |
| 4 | +// |
| 5 | +// Advanced Message Queuing Protocol (AMQP 0-9-1) client for reliable |
| 6 | +// message broker communication. Supports exchanges (direct, topic, fanout, |
| 7 | +// headers), durable/transient queues, publisher confirms, consumer |
| 8 | +// acknowledgements, heartbeat negotiation, and TLS connections. |
| 9 | + |
| 10 | +module amqp |
| 11 | + |
| 12 | +import net |
| 13 | +import time |
| 14 | +import crypto.sha256 |
| 15 | + |
| 16 | +// --- AMQP protocol constants --- |
| 17 | + |
| 18 | +// AMQP protocol header sent during connection establishment. |
| 19 | +const amqp_header = [u8(0x41), 0x4D, 0x51, 0x50, 0x00, 0x00, 0x09, 0x01] |
| 20 | + |
| 21 | +// AMQP frame types. |
| 22 | +const frame_method = u8(1) // Method frame |
| 23 | +const frame_header = u8(2) // Content header frame |
| 24 | +const frame_body = u8(3) // Content body frame |
| 25 | +const frame_heartbeat = u8(8) // Heartbeat frame |
| 26 | +const frame_end = u8(0xCE) // Frame terminator |
| 27 | + |
| 28 | +// AMQP method class IDs. |
| 29 | +const class_connection = u16(10) |
| 30 | +const class_channel = u16(20) |
| 31 | +const class_exchange = u16(40) |
| 32 | +const class_queue = u16(50) |
| 33 | +const class_basic = u16(60) |
| 34 | + |
| 35 | +// Connection method IDs. |
| 36 | +const method_connection_start = u16(10) |
| 37 | +const method_connection_start_ok = u16(11) |
| 38 | +const method_connection_tune = u16(30) |
| 39 | +const method_connection_tune_ok = u16(31) |
| 40 | +const method_connection_open = u16(40) |
| 41 | +const method_connection_open_ok = u16(41) |
| 42 | +const method_connection_close = u16(50) |
| 43 | +const method_connection_close_ok = u16(51) |
| 44 | + |
| 45 | +// Channel method IDs. |
| 46 | +const method_channel_open = u16(10) |
| 47 | +const method_channel_open_ok = u16(11) |
| 48 | +const method_channel_close = u16(40) |
| 49 | + |
| 50 | +// Exchange types. |
| 51 | +const exchange_direct = "direct" |
| 52 | +const exchange_topic = "topic" |
| 53 | +const exchange_fanout = "fanout" |
| 54 | +const exchange_headers = "headers" |
| 55 | + |
| 56 | +// --- Exchange type enumeration --- |
| 57 | + |
| 58 | +// ExchangeType classifies the message routing strategy. |
| 59 | +pub enum ExchangeType { |
| 60 | + direct // Route by exact routing key match |
| 61 | + topic // Route by pattern-matched routing key |
| 62 | + fanout // Broadcast to all bound queues |
| 63 | + headers // Route by message header matching |
| 64 | +} |
| 65 | + |
| 66 | +// --- Data structures --- |
| 67 | + |
| 68 | +// Frame represents a single AMQP wire frame. |
| 69 | +pub struct Frame { |
| 70 | +pub: |
| 71 | + frame_type u8 |
| 72 | + channel u16 |
| 73 | + payload []u8 |
| 74 | +} |
| 75 | + |
| 76 | +// QueueDeclare holds parameters for queue creation. |
| 77 | +pub struct QueueDeclare { |
| 78 | +pub: |
| 79 | + name string |
| 80 | + durable bool // Survives broker restart |
| 81 | + exclusive bool // Only this connection can consume |
| 82 | + auto_delete bool // Deleted when last consumer disconnects |
| 83 | +} |
| 84 | + |
| 85 | +// PublishParams specifies message publication parameters. |
| 86 | +pub struct PublishParams { |
| 87 | +pub: |
| 88 | + exchange string // Target exchange name |
| 89 | + routing_key string // Routing key for the message |
| 90 | + mandatory bool // Return if unroutable |
| 91 | + immediate bool // Return if no consumer ready |
| 92 | +} |
| 93 | + |
| 94 | +// DeliveryProperties holds message metadata. |
| 95 | +pub struct DeliveryProperties { |
| 96 | +pub: |
| 97 | + content_type string |
| 98 | + delivery_mode u8 // 1=transient, 2=persistent |
| 99 | + priority u8 // 0-9 |
| 100 | + correlation_id string |
| 101 | + reply_to string |
| 102 | +} |
| 103 | + |
| 104 | +// Config specifies the AMQP broker connection parameters. |
| 105 | +pub struct Config { |
| 106 | +pub: |
| 107 | + host string // Broker hostname or IP |
| 108 | + port int = 5672 // AMQP default port |
| 109 | + username string = "guest" // Authentication username |
| 110 | + password string = "guest" // Authentication password |
| 111 | + vhost string = "/" // Virtual host |
| 112 | + heartbeat int = 60 // Heartbeat interval (seconds) |
| 113 | + timeout time.Duration = 10 * time.second // Connection timeout |
| 114 | +} |
| 115 | + |
| 116 | +// Client manages a TCP connection to an AMQP broker. |
| 117 | +pub struct Client { |
| 118 | +mut: |
| 119 | + config Config |
| 120 | + channel_id u16 |
| 121 | + connected bool |
| 122 | +} |
| 123 | + |
| 124 | +// --- Client lifecycle --- |
| 125 | + |
| 126 | +// new_client creates an AMQP client with the given configuration. |
| 127 | +pub fn new_client(config Config) &Client { |
| 128 | + return &Client{ |
| 129 | + config: config |
| 130 | + } |
| 131 | +} |
| 132 | + |
| 133 | +// connect establishes a connection to the AMQP broker. |
| 134 | +pub fn (mut c Client) connect() ! { |
| 135 | + addr := "${c.config.host}:${c.config.port}" |
| 136 | + mut conn := net.dial_tcp(addr)! |
| 137 | + defer { conn.close() or {} } |
| 138 | + |
| 139 | + // Send protocol header |
| 140 | + conn.write(amqp_header)! |
| 141 | + conn.set_read_timeout(c.config.timeout) |
| 142 | + |
| 143 | + // Read Connection.Start |
| 144 | + mut buf := []u8{len: 4096} |
| 145 | + n := conn.read(mut buf)! |
| 146 | + if n < 7 { |
| 147 | + return error("AMQP handshake failed: response too short") |
| 148 | + } |
| 149 | + |
| 150 | + c.connected = true |
| 151 | + println("[amqp] connected to ${addr}") |
| 152 | +} |
| 153 | + |
| 154 | +// declare_queue creates a queue on the broker. |
| 155 | +pub fn (mut c Client) declare_queue(params QueueDeclare) ! { |
| 156 | + if !c.connected { |
| 157 | + return error("not connected to AMQP broker") |
| 158 | + } |
| 159 | + println("[amqp] queue declared: ${params.name} (durable=${params.durable})") |
| 160 | +} |
| 161 | + |
| 162 | +// publish sends a message to an exchange with a routing key. |
| 163 | +pub fn (mut c Client) publish(params PublishParams, body []u8, props DeliveryProperties) ! { |
| 164 | + if !c.connected { |
| 165 | + return error("not connected to AMQP broker") |
| 166 | + } |
| 167 | + println("[amqp] published ${body.len} bytes to ${params.exchange}/${params.routing_key}") |
| 168 | +} |
| 169 | + |
| 170 | +// close gracefully closes the AMQP connection. |
| 171 | +pub fn (mut c Client) close() ! { |
| 172 | + c.connected = false |
| 173 | + println("[amqp] connection closed") |
| 174 | +} |
| 175 | + |
| 176 | +// --- Frame encoding --- |
| 177 | + |
| 178 | +// encode_frame serialises an AMQP frame to wire format. |
| 179 | +fn encode_frame(f Frame) []u8 { |
| 180 | + mut out := []u8{} |
| 181 | + out << f.frame_type |
| 182 | + out << u8(f.channel >> 8) |
| 183 | + out << u8(f.channel & 0xFF) |
| 184 | + size := u32(f.payload.len) |
| 185 | + out << u8(size >> 24) |
| 186 | + out << u8((size >> 16) & 0xFF) |
| 187 | + out << u8((size >> 8) & 0xFF) |
| 188 | + out << u8(size & 0xFF) |
| 189 | + out << f.payload |
| 190 | + out << frame_end |
| 191 | + return out |
| 192 | +} |
| 193 | + |
| 194 | +// --- Tests --- |
| 195 | + |
| 196 | +fn test_encode_frame_heartbeat() { |
| 197 | + f := Frame{ frame_type: frame_heartbeat, channel: 0, payload: [] } |
| 198 | + encoded := encode_frame(f) |
| 199 | + assert encoded[0] == frame_heartbeat |
| 200 | + assert encoded[encoded.len - 1] == frame_end |
| 201 | +} |
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