opentelemetry_sdk/propagation/
baggage.rs

1use opentelemetry::{
2    baggage::{BaggageExt, KeyValueMetadata},
3    otel_warn,
4    propagation::{text_map_propagator::FieldIter, Extractor, Injector, TextMapPropagator},
5    Context,
6};
7use percent_encoding::{percent_decode_str, utf8_percent_encode, AsciiSet, CONTROLS};
8use std::iter;
9use std::sync::OnceLock;
10
11static BAGGAGE_HEADER: &str = "baggage";
12const FRAGMENT: &AsciiSet = &CONTROLS.add(b' ').add(b'"').add(b';').add(b',').add(b'=');
13
14// TODO Replace this with LazyLock once it is stable.
15static BAGGAGE_FIELDS: OnceLock<[String; 1]> = OnceLock::new();
16#[inline]
17fn baggage_fields() -> &'static [String; 1] {
18    BAGGAGE_FIELDS.get_or_init(|| [BAGGAGE_HEADER.to_owned()])
19}
20
21/// Propagates name-value pairs in [W3C Baggage] format.
22///
23/// Baggage is used to annotate telemetry, adding context and
24/// information to metrics, traces, and logs. It is an abstract data type
25/// represented by a set of name-value pairs describing user-defined properties.
26/// Each name in a [`Baggage`] is associated with exactly one value.
27/// `Baggage`s are serialized according to the editor's draft of
28/// the [W3C Baggage] specification.
29///
30/// # Examples
31///
32/// ```
33/// use opentelemetry::{baggage::BaggageExt, KeyValue, propagation::TextMapPropagator};
34/// use opentelemetry_sdk::propagation::BaggagePropagator;
35/// use std::collections::HashMap;
36///
37/// // Example baggage value passed in externally via http headers
38/// let mut headers = HashMap::new();
39/// headers.insert("baggage".to_string(), "user_id=1".to_string());
40///
41/// let propagator = BaggagePropagator::new();
42/// // can extract from any type that impls `Extractor`, usually an HTTP header map
43/// let cx = propagator.extract(&headers);
44///
45/// // Iterate over extracted name-value pairs
46/// for (name, value) in cx.baggage() {
47///     // ...
48/// }
49///
50/// // Add new baggage
51/// let cx_with_additions = cx.with_baggage(vec![KeyValue::new("server_id", 42)]);
52///
53/// // Inject baggage into http request
54/// propagator.inject_context(&cx_with_additions, &mut headers);
55///
56/// let header_value = headers.get("baggage").expect("header is injected");
57/// assert!(header_value.contains("user_id=1"), "still contains previous name-value");
58/// assert!(header_value.contains("server_id=42"), "contains new name-value pair");
59/// ```
60///
61/// [W3C Baggage]: https://w3c.github.io/baggage
62/// [`Baggage`]: opentelemetry::baggage::Baggage
63#[derive(Debug, Default)]
64pub struct BaggagePropagator {
65    _private: (),
66}
67
68impl BaggagePropagator {
69    /// Construct a new baggage propagator.
70    pub fn new() -> Self {
71        BaggagePropagator { _private: () }
72    }
73}
74
75impl TextMapPropagator for BaggagePropagator {
76    /// Encodes the values of the `Context` and injects them into the provided `Injector`.
77    fn inject_context(&self, cx: &Context, injector: &mut dyn Injector) {
78        let baggage = cx.baggage();
79        if !baggage.is_empty() {
80            let header_value = baggage
81                .iter()
82                .map(|(name, (value, metadata))| {
83                    let metadata_str = metadata.as_str().trim();
84                    let metadata_prefix = if metadata_str.is_empty() { "" } else { ";" };
85                    utf8_percent_encode(name.as_str().trim(), FRAGMENT)
86                        .chain(iter::once("="))
87                        .chain(utf8_percent_encode(value.as_str().trim(), FRAGMENT))
88                        .chain(iter::once(metadata_prefix))
89                        .chain(iter::once(metadata_str))
90                        .collect()
91                })
92                .collect::<Vec<String>>()
93                .join(",");
94            injector.set(BAGGAGE_HEADER, header_value);
95        }
96    }
97
98    /// Extracts a `Context` with baggage values from a `Extractor`.
99    fn extract_with_context(&self, cx: &Context, extractor: &dyn Extractor) -> Context {
100        if let Some(header_value) = extractor.get(BAGGAGE_HEADER) {
101            let baggage = header_value.split(',').flat_map(|context_value| {
102                if let Some((name_and_value, props)) = context_value
103                    .split(';')
104                    .collect::<Vec<&str>>()
105                    .split_first()
106                {
107                    let mut iter = name_and_value.split('=');
108                    if let (Some(name), Some(value)) = (iter.next(), iter.next()) {
109                        let decode_name = percent_decode_str(name).decode_utf8();
110                        let decode_value = percent_decode_str(value).decode_utf8();
111
112                        if let (Ok(name), Ok(value)) = (decode_name, decode_value) {
113                            // Here we don't store the first ; into baggage since it should be treated
114                            // as separator rather part of metadata
115                            let decoded_props = props
116                                .iter()
117                                .flat_map(|prop| percent_decode_str(prop).decode_utf8())
118                                .map(|prop| prop.trim().to_string())
119                                .collect::<Vec<String>>()
120                                .join(";"); // join with ; because we deleted all ; when calling split above
121
122                            Some(KeyValueMetadata::new(
123                                name.trim().to_owned(),
124                                value.trim().to_string(),
125                                decoded_props.as_str(),
126                            ))
127                        } else {
128                            otel_warn!(
129                                name: "BaggagePropagator.Extract.InvalidUTF8",
130                                message = "Invalid UTF8 string in key values",
131                                baggage_header = header_value,
132                            );
133                            None
134                        }
135                    } else {
136                        otel_warn!(
137                            name: "BaggagePropagator.Extract.InvalidKeyValueFormat",
138                            message = "Invalid baggage key-value format",
139                            baggage_header = header_value,
140                        );
141                        None
142                    }
143                } else {
144                    otel_warn!(
145                        name: "BaggagePropagator.Extract.InvalidFormat",
146                        message = "Invalid baggage format",
147                        baggage_header = header_value);
148                    None
149                }
150            });
151            cx.with_baggage(baggage)
152        } else {
153            cx.clone()
154        }
155    }
156
157    fn fields(&self) -> FieldIter<'_> {
158        FieldIter::new(baggage_fields())
159    }
160}
161
162#[cfg(test)]
163mod tests {
164    use super::*;
165    use opentelemetry::{baggage::BaggageMetadata, Key, KeyValue, StringValue, Value};
166    use std::collections::HashMap;
167
168    #[rustfmt::skip]
169    fn valid_extract_data() -> Vec<(&'static str, HashMap<Key, Value>)> {
170        vec![
171            // "valid w3cHeader"
172            ("key1=val1,key2=val2", vec![(Key::new("key1"), Value::from("val1")), (Key::new("key2"), Value::from("val2"))].into_iter().collect()),
173            // "valid w3cHeader with spaces"
174            ("key1 =   val1,  key2 =val2   ", vec![(Key::new("key1"), Value::from("val1")), (Key::new("key2"), Value::from("val2"))].into_iter().collect()),
175            // "valid header with url-escaped comma"
176            ("key1=val1,key2=val2%2Cval3", vec![(Key::new("key1"), Value::from("val1")), (Key::new("key2"), Value::from("val2,val3"))].into_iter().collect()),
177            // "valid header with an invalid header"
178            ("key1=val1,key2=val2,a,val3", vec![(Key::new("key1"), Value::from("val1")), (Key::new("key2"), Value::from("val2"))].into_iter().collect()),
179            // "valid header with no value"
180            ("key1=,key2=val2", vec![(Key::new("key1"), Value::from("")), (Key::new("key2"), Value::from("val2"))].into_iter().collect()),
181        ]
182    }
183
184    #[rustfmt::skip]
185    #[allow(clippy::type_complexity)]
186    fn valid_extract_data_with_metadata() -> Vec<(&'static str, HashMap<Key, (Value, BaggageMetadata)>)> {
187        vec![
188            // "valid w3cHeader with properties"
189            ("key1=val1,key2=val2;prop=1", vec![(Key::new("key1"), (Value::from("val1"), BaggageMetadata::default())), (Key::new("key2"), (Value::from("val2"), BaggageMetadata::from("prop=1")))].into_iter().collect()),
190            // prop can don't need to be key value pair
191            ("key1=val1,key2=val2;prop1", vec![(Key::new("key1"), (Value::from("val1"), BaggageMetadata::default())), (Key::new("key2"), (Value::from("val2"), BaggageMetadata::from("prop1")))].into_iter().collect()),
192            ("key1=value1;property1;property2, key2 = value2, key3=value3; propertyKey=propertyValue",
193             vec![
194                 (Key::new("key1"), (Value::from("value1"), BaggageMetadata::from("property1;property2"))),
195                 (Key::new("key2"), (Value::from("value2"), BaggageMetadata::default())),
196                 (Key::new("key3"), (Value::from("value3"), BaggageMetadata::from("propertyKey=propertyValue"))),
197             ].into_iter().collect()),
198        ]
199    }
200
201    #[rustfmt::skip]
202    fn valid_inject_data() -> Vec<(Vec<KeyValue>, Vec<&'static str>)> {
203        vec![
204            // "two simple values"
205            (vec![KeyValue::new("key1", "val1"), KeyValue::new("key2", "val2")], vec!["key1=val1", "key2=val2"]),
206            // "two values with escaped chars"
207            (vec![KeyValue::new("key1", "val1,val2"), KeyValue::new("key2", "val3=4")], vec!["key1=val1%2Cval2", "key2=val3%3D4"]),
208            // "values of non-string non-array types"
209            (
210                vec![
211                    KeyValue::new("key1", true),
212                    KeyValue::new("key2", Value::I64(123)),
213                    KeyValue::new("key3", Value::F64(123.567)),
214                ],
215                vec![
216                    "key1=true",
217                    "key2=123",
218                    "key3=123.567",
219                ],
220            ),
221            // "values of array types"
222            (
223                vec![
224                    KeyValue::new("key1", Value::Array(vec![true, false].into())),
225                    KeyValue::new("key2", Value::Array(vec![123, 456].into())),
226                    KeyValue::new("key3", Value::Array(vec![StringValue::from("val1"), StringValue::from("val2")].into())),
227                ],
228                vec![
229                    "key1=[true%2Cfalse]",
230                    "key2=[123%2C456]",
231                    "key3=[%22val1%22%2C%22val2%22]",
232                ],
233            ),
234        ]
235    }
236
237    #[rustfmt::skip]
238    fn valid_inject_data_metadata() -> Vec<(Vec<KeyValueMetadata>, Vec<&'static str>)> {
239        vec![
240            (
241                vec![
242                    KeyValueMetadata::new("key1", "val1", "prop1"),
243                    KeyValue::new("key2", "val2").into(),
244                    KeyValueMetadata::new("key3", "val3", "anykey=anyvalue"),
245                ],
246                vec![
247                    "key1=val1;prop1",
248                    "key2=val2",
249                    "key3=val3;anykey=anyvalue",
250                ],
251            )
252        ]
253    }
254
255    #[test]
256    fn extract_baggage() {
257        let propagator = BaggagePropagator::new();
258
259        for (header_value, kvs) in valid_extract_data() {
260            let mut extractor: HashMap<String, String> = HashMap::new();
261            extractor.insert(BAGGAGE_HEADER.to_string(), header_value.to_string());
262            let context = propagator.extract(&extractor);
263            let baggage = context.baggage();
264
265            assert_eq!(kvs.len(), baggage.len());
266            for (key, (value, _metadata)) in baggage {
267                assert_eq!(Some(value), kvs.get(key))
268            }
269        }
270    }
271
272    #[test]
273    fn inject_baggage() {
274        let propagator = BaggagePropagator::new();
275
276        for (kvm, header_parts) in valid_inject_data() {
277            let mut injector = HashMap::new();
278            let cx = Context::current_with_baggage(kvm);
279            propagator.inject_context(&cx, &mut injector);
280            let header_value = injector.get(BAGGAGE_HEADER).unwrap();
281            assert_eq!(header_parts.join(",").len(), header_value.len(),);
282            for header_part in &header_parts {
283                assert!(header_value.contains(header_part),)
284            }
285        }
286    }
287
288    #[test]
289    fn extract_baggage_with_metadata() {
290        let propagator = BaggagePropagator::new();
291        for (header_value, kvm) in valid_extract_data_with_metadata() {
292            let mut extractor: HashMap<String, String> = HashMap::new();
293            extractor.insert(BAGGAGE_HEADER.to_string(), header_value.to_string());
294            let context = propagator.extract(&extractor);
295            let baggage = context.baggage();
296
297            assert_eq!(kvm.len(), baggage.len());
298            for (key, value_and_prop) in baggage {
299                assert_eq!(Some(value_and_prop), kvm.get(key))
300            }
301        }
302    }
303
304    #[test]
305    fn inject_baggage_with_metadata() {
306        let propagator = BaggagePropagator::new();
307
308        for (kvm, header_parts) in valid_inject_data_metadata() {
309            let mut injector = HashMap::new();
310            let cx = Context::current_with_baggage(kvm);
311            propagator.inject_context(&cx, &mut injector);
312            let header_value = injector.get(BAGGAGE_HEADER).unwrap();
313
314            assert_eq!(header_parts.join(",").len(), header_value.len());
315            for header_part in &header_parts {
316                assert!(header_value.contains(header_part),)
317            }
318        }
319    }
320}
opentelemetry_sdk/propagation/baggage.rs

opentelemetry_sdk/propagation/
baggage.rs
