|
| 1 | +use crate::headers; |
| 2 | +use cloudevents::event::SpecVersion; |
| 3 | +use cloudevents::message::{ |
| 4 | + BinaryDeserializer, BinarySerializer, Encoding, MessageAttributeValue, MessageDeserializer, |
| 5 | + Result, StructuredDeserializer, StructuredSerializer, |
| 6 | +}; |
| 7 | +use cloudevents::{message, Event}; |
| 8 | +use rdkafka::message::{BorrowedMessage, Headers, Message, OwnedMessage}; |
| 9 | +use std::collections::HashMap; |
| 10 | +use std::convert::TryFrom; |
| 11 | +use std::str; |
| 12 | + |
| 13 | +/// Wrapper for [`Message`] that implements [`MessageDeserializer`] trait. |
| 14 | +pub struct ConsumerRecordDeserializer { |
| 15 | + pub(crate) headers: HashMap<String, Vec<u8>>, |
| 16 | + pub(crate) payload: Option<Vec<u8>>, |
| 17 | +} |
| 18 | + |
| 19 | +impl ConsumerRecordDeserializer { |
| 20 | + fn get_kafka_headers(message: &impl Message) -> Result<HashMap<String, Vec<u8>>> { |
| 21 | + let mut hm = HashMap::new(); |
| 22 | + let headers = message |
| 23 | + .headers() |
| 24 | + // TODO create an error variant for invalid headers |
| 25 | + .ok_or(cloudevents::message::Error::WrongEncoding {})?; |
| 26 | + for i in 0..headers.count() { |
| 27 | + let header = headers.get(i).unwrap(); |
| 28 | + hm.insert(header.0.to_string(), Vec::from(header.1)); |
| 29 | + } |
| 30 | + Ok(hm) |
| 31 | + } |
| 32 | + |
| 33 | + pub fn new(message: &impl Message) -> Result<ConsumerRecordDeserializer> { |
| 34 | + Ok(ConsumerRecordDeserializer { |
| 35 | + headers: Self::get_kafka_headers(message)?, |
| 36 | + payload: message.payload().map(|s| Vec::from(s)), |
| 37 | + }) |
| 38 | + } |
| 39 | +} |
| 40 | + |
| 41 | +impl BinaryDeserializer for ConsumerRecordDeserializer { |
| 42 | + fn deserialize_binary<R: Sized, V: BinarySerializer<R>>(mut self, mut visitor: V) -> Result<R> { |
| 43 | + if self.encoding() != Encoding::BINARY { |
| 44 | + return Err(message::Error::WrongEncoding {}); |
| 45 | + } |
| 46 | + |
| 47 | + let spec_version = SpecVersion::try_from( |
| 48 | + str::from_utf8(&self.headers.remove(headers::SPEC_VERSION_HEADER).unwrap()[..]) |
| 49 | + .map_err(|e| cloudevents::message::Error::Other { |
| 50 | + source: Box::new(e), |
| 51 | + })?, |
| 52 | + )?; |
| 53 | + |
| 54 | + visitor = visitor.set_spec_version(spec_version.clone())?; |
| 55 | + |
| 56 | + let attributes = spec_version.attribute_names(); |
| 57 | + |
| 58 | + if let Some(hv) = self.headers.remove(headers::CONTENT_TYPE) { |
| 59 | + visitor = visitor.set_attribute( |
| 60 | + "datacontenttype", |
| 61 | + MessageAttributeValue::String(String::from_utf8(hv).map_err(|e| { |
| 62 | + cloudevents::message::Error::Other { |
| 63 | + source: Box::new(e), |
| 64 | + } |
| 65 | + })?), |
| 66 | + )? |
| 67 | + } |
| 68 | + |
| 69 | + for (hn, hv) in self |
| 70 | + .headers |
| 71 | + .into_iter() |
| 72 | + .filter(|(hn, _)| headers::SPEC_VERSION_HEADER != *hn && hn.starts_with("ce_")) |
| 73 | + { |
| 74 | + let name = &hn["ce_".len()..]; |
| 75 | + |
| 76 | + if attributes.contains(&name) { |
| 77 | + visitor = visitor.set_attribute( |
| 78 | + name, |
| 79 | + MessageAttributeValue::String(String::from_utf8(hv).map_err(|e| { |
| 80 | + cloudevents::message::Error::Other { |
| 81 | + source: Box::new(e), |
| 82 | + } |
| 83 | + })?), |
| 84 | + )? |
| 85 | + } else { |
| 86 | + visitor = visitor.set_extension( |
| 87 | + name, |
| 88 | + MessageAttributeValue::String(String::from_utf8(hv).map_err(|e| { |
| 89 | + cloudevents::message::Error::Other { |
| 90 | + source: Box::new(e), |
| 91 | + } |
| 92 | + })?), |
| 93 | + )? |
| 94 | + } |
| 95 | + } |
| 96 | + |
| 97 | + if self.payload != None { |
| 98 | + visitor.end_with_data(self.payload.unwrap()) |
| 99 | + } else { |
| 100 | + visitor.end() |
| 101 | + } |
| 102 | + } |
| 103 | +} |
| 104 | + |
| 105 | +impl StructuredDeserializer for ConsumerRecordDeserializer { |
| 106 | + fn deserialize_structured<R: Sized, V: StructuredSerializer<R>>(self, visitor: V) -> Result<R> { |
| 107 | + if self.encoding() != Encoding::STRUCTURED { |
| 108 | + return Err(message::Error::WrongEncoding {}); |
| 109 | + } |
| 110 | + visitor.set_structured_event(self.payload.unwrap()) |
| 111 | + } |
| 112 | +} |
| 113 | + |
| 114 | +impl MessageDeserializer for ConsumerRecordDeserializer { |
| 115 | + fn encoding(&self) -> Encoding { |
| 116 | + match ( |
| 117 | + self.headers |
| 118 | + .get("content-type") |
| 119 | + .map(|s| String::from_utf8(s.to_vec()).ok()) |
| 120 | + .flatten() |
| 121 | + .map(|s| s.starts_with(headers::CLOUDEVENTS_JSON_HEADER)) |
| 122 | + .unwrap_or(false), |
| 123 | + self.headers.get(headers::SPEC_VERSION_HEADER), |
| 124 | + ) { |
| 125 | + (true, _) => Encoding::STRUCTURED, |
| 126 | + (_, Some(_)) => Encoding::BINARY, |
| 127 | + _ => Encoding::UNKNOWN, |
| 128 | + } |
| 129 | + } |
| 130 | +} |
| 131 | + |
| 132 | +/// Method to transform a [`Message`] to [`Event`]. |
| 133 | +pub fn record_to_event(msg: &impl Message) -> Result<Event> { |
| 134 | + MessageDeserializer::into_event(ConsumerRecordDeserializer::new(msg)?) |
| 135 | +} |
| 136 | + |
| 137 | +/// Extension Trait for [`Message`] which acts as a wrapper for the function [`record_to_event()`] |
| 138 | +pub trait MessageExt { |
| 139 | + /// Generates [`Event`] from [`BorrowedMessage`]. |
| 140 | + fn to_event(&self) -> Result<Event>; |
| 141 | +} |
| 142 | + |
| 143 | +impl MessageExt for BorrowedMessage<'_> { |
| 144 | + fn to_event(&self) -> Result<Event> { |
| 145 | + record_to_event(self) |
| 146 | + } |
| 147 | +} |
| 148 | + |
| 149 | +impl MessageExt for OwnedMessage { |
| 150 | + fn to_event(&self) -> Result<Event> { |
| 151 | + record_to_event(self) |
| 152 | + } |
| 153 | +} |
| 154 | + |
| 155 | +#[cfg(test)] |
| 156 | +mod tests { |
| 157 | + use super::*; |
| 158 | + use crate::kafka_producer_record::MessageRecord; |
| 159 | + |
| 160 | + use chrono::Utc; |
| 161 | + use cloudevents::{EventBuilder, EventBuilderV10}; |
| 162 | + use serde_json::json; |
| 163 | + |
| 164 | + #[test] |
| 165 | + fn test_binary_record() { |
| 166 | + let time = Utc::now(); |
| 167 | + |
| 168 | + let expected = EventBuilderV10::new() |
| 169 | + .id("0001") |
| 170 | + .ty("example.test") |
| 171 | + .time(time) |
| 172 | + .source("http://localhost") |
| 173 | + .extension("someint", "10") |
| 174 | + .build() |
| 175 | + .unwrap(); |
| 176 | + |
| 177 | + // Since there is neither a way provided by rust-rdkafka to convert FutureProducer back into |
| 178 | + // OwnedMessage or BorrowedMessage, nor is there a way to create a BorrowedMessage struct, |
| 179 | + // the test uses OwnedMessage instead, which consumes the message instead of borrowing it like |
| 180 | + // in the case of BorrowedMessage |
| 181 | + |
| 182 | + let message_record = MessageRecord::from_event( |
| 183 | + EventBuilderV10::new() |
| 184 | + .id("0001") |
| 185 | + .ty("example.test") |
| 186 | + .time(time) |
| 187 | + .source("http://localhost") |
| 188 | + .extension("someint", "10") |
| 189 | + .build() |
| 190 | + .unwrap(), |
| 191 | + ) |
| 192 | + .unwrap(); |
| 193 | + |
| 194 | + let owned_message = OwnedMessage::new( |
| 195 | + message_record.payload, |
| 196 | + Some(String::from("test key").into_bytes()), |
| 197 | + String::from("test topic"), |
| 198 | + rdkafka::message::Timestamp::NotAvailable, |
| 199 | + 10, |
| 200 | + 10, |
| 201 | + Some(message_record.headers), |
| 202 | + ); |
| 203 | + |
| 204 | + assert_eq!(owned_message.to_event().unwrap(), expected) |
| 205 | + } |
| 206 | + |
| 207 | + #[test] |
| 208 | + fn test_structured_record() { |
| 209 | + let j = json!({"hello": "world"}); |
| 210 | + |
| 211 | + let expected = EventBuilderV10::new() |
| 212 | + .id("0001") |
| 213 | + .ty("example.test") |
| 214 | + .source("http://localhost") |
| 215 | + .data("application/json", j.clone()) |
| 216 | + .extension("someint", "10") |
| 217 | + .build() |
| 218 | + .unwrap(); |
| 219 | + |
| 220 | + // Since there is neither a way provided by rust-rdkafka to convert FutureProducer back into |
| 221 | + // OwnedMessage or BorrowedMessage, nor is there a way to create a BorrowedMessage struct, |
| 222 | + // the test uses OwnedMessage instead, which consumes the message instead of borrowing it like |
| 223 | + // in the case of BorrowedMessage |
| 224 | + |
| 225 | + let input = EventBuilderV10::new() |
| 226 | + .id("0001") |
| 227 | + .ty("example.test") |
| 228 | + .source("http://localhost") |
| 229 | + .data("application/json", j.clone()) |
| 230 | + .extension("someint", "10") |
| 231 | + .build() |
| 232 | + .unwrap(); |
| 233 | + |
| 234 | + let serialized_event = |
| 235 | + StructuredDeserializer::deserialize_structured(input, MessageRecord::new()).unwrap(); |
| 236 | + |
| 237 | + let owned_message = OwnedMessage::new( |
| 238 | + serialized_event.payload, |
| 239 | + Some(String::from("test key").into_bytes()), |
| 240 | + String::from("test topic"), |
| 241 | + rdkafka::message::Timestamp::NotAvailable, |
| 242 | + 10, |
| 243 | + 10, |
| 244 | + Some(serialized_event.headers), |
| 245 | + ); |
| 246 | + |
| 247 | + assert_eq!(owned_message.to_event().unwrap(), expected) |
| 248 | + } |
| 249 | +} |
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