3 releases

0.1.4 Mar 26, 2021
0.1.3 Mar 17, 2021
0.1.2 Mar 17, 2021

#220 in Parser implementations

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Very flexible Rust library for parsing syslog based on RFC 5424. Uses nom as the sole dependency.


  • This thing is fast. It is 50% faster than rust-syslog-rfc5424 if you are ok with an Option<&str> for TIMESTAMP. And they are on pair when having the chrono-timestamp feature on (parses TIMESTAMP as chrono DateTime<Offset> type). Compared to any Ruby/Python/Js implementation is obviously an order of magnitude faster. It's not super optimized for performance (especially around SD) and I suspect that rust-syslog-rfc5424 is not either. In any case, performance isn't the main goal of rsyslog. It's flexibility.
  • it allows you to inject your own TIMESTAMP, SD and MSG parsers in case of a need. All you need is to implement the necessary traits and inject the type when you specify the parser type. In my case I needed to parse a syslog that has invalid SD (basically it's not there at all, looking at you Heroku) and a msg parser that is capable of parsing raw messages as well as Heroku router message format. You can see an example in example/multitype.
  • It allows you to parse on the fly multiple messages, without having to traverse the initial string all the way to find the breakpoints (usually new line) and then breakit into substrings in a Vec. All you need is to inject a MSG parser that will make sure it stops when it should stop. Then you can use the iterator that will allow you to iterate and parse each substring.
  • Rsyslog provides some common implementations of some TIMESTAMP, STRUCTURED DATA and MSG parsers.

Cargo features

Optional features:

  • chrono-timestamp: Allows you to parse TIMESTAMP as Option<chrono::DateTime<chrono::FixedOffset>>.
  • serde-serialize: Allows you to serialize the Message struct using serde.

Example of usage

Simple message

let msg = r#"<29>1 2016-02-21T04:32:57+00:00 web1 someservice - - [origin x-service="someservice"][meta sequenceId="14125553"] - - 1456029177 "GET /v1/ok HTTP/1.1" 200 145 "-" "hacheck 0.9.0" 24306 575"#;
let message: Message = rsyslog::Message::parse(msg)?;

By default Message type is Message<'a, Option<&'a str>, Vec<StructuredData>, Raw<'a>> using default generic type params.

Multiline message

type OneLineMessage<'a> = Message<'a, Option<&'a str>, Vec<StructuredData<'a>>, LineRaw<'a>>;

let msg = r#"<29>1 2016-02-21T04:32:57+00:00 web1 someservice - - - - - 1456029177 "GET /v1/info HTTP/1.1" 200 145 "-" "hacheck 0.9.0" 24306 575
<29>1 2016-02-21T05:32:57+00:00 web2 someservice - - - - - 1456029177 "GET /v1/videos HTTP/1.1" 200 145 "-" "hacheck 0.9.0" 24306 575
<29>1 2016-02-21T06:32:57+00:00 web3 someservice - - - - - 1456029177 "GET /v1/users HTTP/1.1" 200 145 "-" "hacheck 0.9.0" 24306 575"#;

let hostnames = OneLineMessage::iter(msg)
    .map(|s| s.map(|s| s.hostname))

You can find more examples in the examples directory.


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