init-tracing-opentelemetry 0.17.0

A set of helpers to initialize (and more) tracing + opentelemetry (compose your own or use opinionated preset)
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133

//#![warn(missing_docs)]
#![forbid(unsafe_code)]
#![warn(clippy::perf)]
#![warn(clippy::pedantic)]
#![allow(clippy::module_name_repetitions)]
#![allow(clippy::missing_errors_doc)]
#![doc = include_str!("../README.md")]

mod error;
pub use error::Error;

use opentelemetry::propagation::TextMapPropagator;
use opentelemetry::trace::TraceError;
use opentelemetry_sdk::propagation::{
    BaggagePropagator, TextMapCompositePropagator, TraceContextPropagator,
};

#[cfg(feature = "jaeger")]
pub mod jaeger;
#[cfg(feature = "otlp")]
pub mod otlp;
#[cfg(feature = "tracer")]
pub mod resource;
#[cfg(feature = "stdout")]
pub mod stdio;
#[cfg(feature = "tracing_subscriber_ext")]
pub mod tracing_subscriber_ext;

/// Configure the global propagator based on content of the env variable [OTEL_PROPAGATORS](https://opentelemetry.io/docs/concepts/sdk-configuration/general-sdk-configuration/#otel_propagators)
/// Specifies Propagators to be used in a comma-separated list.
/// Default value: `"tracecontext,baggage"`
/// Example: `export OTEL_PROPAGATORS="b3"`
/// Accepted values for `OTEL_PROPAGATORS` are:
///
/// - "tracecontext": W3C Trace Context
/// - "baggage": W3C Baggage
/// - "b3": B3 Single (require feature "zipkin")
/// - "b3multi": B3 Multi (require feature "zipkin")
/// - "jaeger": Jaeger (require feature "jaeger")
/// - "xray": AWS X-Ray (require feature "xray")
/// - "ottrace": OT Trace (third party) (not supported)
/// - "none": No automatically configured propagator.
///
/// # Errors
///
/// Will return `TraceError` if issue in reading or instanciate propagator.
pub fn init_propagator() -> Result<(), TraceError> {
    let value_from_env =
        std::env::var("OTEL_PROPAGATORS").unwrap_or_else(|_| "tracecontext,baggage".to_string());
    let propagators: Vec<(Box<dyn TextMapPropagator + Send + Sync>, String)> = value_from_env
        .split(',')
        .map(|s| {
            let name = s.trim().to_lowercase();
            propagator_from_string(&name).map(|o| o.map(|b| (b, name)))
        })
        .collect::<Result<Vec<_>, _>>()?
        .into_iter()
        .flatten()
        .collect();
    if !propagators.is_empty() {
        let (propagators_impl, propagators_name): (Vec<_>, Vec<_>) =
            propagators.into_iter().unzip();
        tracing::debug!(target: "otel::setup", OTEL_PROPAGATORS = propagators_name.join(","));
        let composite_propagator = TextMapCompositePropagator::new(propagators_impl);
        opentelemetry::global::set_text_map_propagator(composite_propagator);
    }
    Ok(())
}

#[allow(clippy::box_default)]
fn propagator_from_string(
    v: &str,
) -> Result<Option<Box<dyn TextMapPropagator + Send + Sync>>, TraceError> {
    match v {
        "tracecontext" => Ok(Some(Box::new(TraceContextPropagator::new()))),
        "baggage" => Ok(Some(Box::new(BaggagePropagator::new()))),
        #[cfg(feature = "zipkin")]
        "b3" => Ok(Some(Box::new(
            opentelemetry_zipkin::Propagator::with_encoding(
                opentelemetry_zipkin::B3Encoding::SingleHeader,
            ),
        ))),
        #[cfg(not(feature = "zipkin"))]
        "b3" => Err(TraceError::from(
            "unsupported propagators form env OTEL_PROPAGATORS: 'b3', try to enable compile feature 'zipkin'"
        )),
        #[cfg(feature = "zipkin")]
        "b3multi" => Ok(Some(Box::new(
            opentelemetry_zipkin::Propagator::with_encoding(
                opentelemetry_zipkin::B3Encoding::MultipleHeader,
            ),
        ))),
        #[cfg(not(feature = "zipkin"))]
        "b3multi" => Err(TraceError::from(
            "unsupported propagators form env OTEL_PROPAGATORS: 'b3multi', try to enable compile feature 'zipkin'"
        )),
        #[cfg(feature = "jaeger")]
        "jaeger" => Ok(Some(Box::new(
            opentelemetry_jaeger::Propagator::default()
        ))),
        #[cfg(not(feature = "jaeger"))]
        "jaeger" => Err(TraceError::from(
            "unsupported propagators form env OTEL_PROPAGATORS: 'jaeger', try to enable compile feature 'jaeger'"
        )),
        #[cfg(feature = "xray")]
        "xray" => Ok(Some(Box::new(
            opentelemetry_aws::trace::XrayPropagator::default(),
        ))),
        #[cfg(not(feature = "xray"))]
        "xray" => Err(TraceError::from(
            "unsupported propagators form env OTEL_PROPAGATORS: 'xray', try to enable compile feature 'xray'"
        )),
        "none" => Ok(None),
        unknown => Err(TraceError::from(format!(
            "unsupported propagators form env OTEL_PROPAGATORS: '{unknown}'"
        ))),
    }
}

#[cfg(test)]
#[cfg(feature = "tracer")]
mod tests {
    use assert2::let_assert;

    #[test]
    fn init_tracing_failed_on_invalid_propagator() {
        let_assert!(Err(_) = super::propagator_from_string("xxxxxx"));

        // std::env::set_var("OTEL_PROPAGATORS", "xxxxxx");
        // dbg!(std::env::var("OTEL_PROPAGATORS"));
        // let_assert!(Err(_) = init_tracing());
    }
}