interface

#OpenTelemetry Baggage API

This package models the baggage values that move alongside trace context across process boundaries.

#Main types

BaggageMetadata: metadata text attached to one baggage item
KeyValueMetadata: one baggage key, value, and metadata triple
Baggage: immutable baggage container

#Limits and validation

The implementation enforces a few constraints when inserting entries:

at most 64 entries
at most 8192 bytes across the serialized key/value pairs
key length at most 256 characters
value length at most 256 characters

Invalid keys or values, entry-count overflow, and total-size overflow do not raise errors. The original baggage value is returned unchanged.

#Method behavior

#BaggageMetadata

BaggageMetadata::new(metadata): trims surrounding whitespace and stores the remaining text
BaggageMetadata::as_string(): returns the stored metadata text
Default::default(): returns empty metadata

#KeyValueMetadata

KeyValueMetadata::new(key, value, metadata?): packages one baggage entry description; validation happens when the entry is inserted into a Baggage

#Baggage

Baggage::new(): returns an empty baggage value
Baggage::insert(key, value): inserts or replaces one entry with empty metadata
Baggage::insert_with_metadata(key, value, metadata): inserts or replaces one entry with metadata; invalid input leaves the baggage unchanged
Baggage::remove(key): returns a new baggage value without key
Baggage::get(key): returns only the entry value
Baggage::get_with_metadata(key): returns both the value and metadata
Baggage::entries(): returns a detached array of entries
Baggage::len(): returns the number of entries
Baggage::is_empty(): reports whether there are no entries

#When to use this package

Use interface/baggage when you need the public OpenTelemetry baggage model. The SDK uses the same public baggage and context types, so application and library code can pass baggage through interface/context without conversion.

Baggage

source

pub struct Baggage {
  entries : Map[String, KeyValueMetadata]
  kv_content_len : Int
} derive(Eq, ToJson, @moonbitlang/core/debug.Debug
Debug)

Immutable baggage map used for cross-process propagation.

The implementation enforces OpenTelemetry-style limits on key count and serialized size. Updates that violate those limits leave the baggage unchanged. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#overview

impl Default for Baggage

Baggage::entries

source

fn Baggage::entries(self : Baggage) -> Array[KeyValueMetadata]

Returns all baggage entries as an array.

The returned array is detached from the internal map. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#get-all-values

Baggage::get

source

fn Baggage::get(self : Baggage, key : StringView) -> String?

Looks up the string value for key. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#get-value

Baggage::get_with_metadata

source

fn Baggage::get_with_metadata(self : Baggage, key : StringView) -> (String, BaggageMetadata)?

Looks up the value and metadata for key. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#get-all-values

Baggage::insert

source

fn Baggage::insert(self : Baggage, key : StringView, value : StringView) -> Baggage

Inserts one baggage item with empty metadata.

Invalid keys or values, entry-count overflow, and total-size overflow leave the baggage unchanged. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#set-value

Baggage::insert_with_metadata

source

fn Baggage::insert_with_metadata(self : Baggage, key : StringView, value : StringView, metadata : BaggageMetadata) -> Baggage

Inserts or replaces one baggage item together with explicit metadata.

Keys are trimmed before validation. Invalid data or limit violations return the original baggage unchanged. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#set-value

Baggage::is_empty

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fn Baggage::is_empty(self : Baggage) -> Bool

Returns whether the baggage contains no entries. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#get-all-values

Baggage::len

source

fn Baggage::len(self : Baggage) -> Int

Returns the current number of baggage entries. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#get-all-values

Baggage::new

source

fn Baggage::new() -> Baggage

Returns an empty baggage value. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#overview

Baggage::remove

source

fn Baggage::remove(self : Baggage, key : StringView) -> Baggage

Returns a new baggage value without key.

Removing a missing key still returns a fresh baggage value with the same contents. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#remove-value

BaggageMetadata

source

pub struct BaggageMetadata {
  metadata : String
} derive(Compare, Eq, Hash, ToJson, @moonbitlang/core/debug.Debug
Debug)

Metadata attached to one baggage entry.

The stored text is trimmed when constructed. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#overview

impl Default for BaggageMetadata

BaggageMetadata::as_string

source

fn BaggageMetadata::as_string(self : BaggageMetadata) -> String

Returns the stored metadata text. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#overview

BaggageMetadata::new

source

fn BaggageMetadata::new(metadata : StringView) -> BaggageMetadata

Creates metadata from one text fragment after trimming surrounding whitespace. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#set-value

KeyValueMetadata

source

pub struct KeyValueMetadata {
  key : @moonbit-community/opentelemetry/interface/common.Key
Key
  value : String
  metadata : BaggageMetadata
} derive(Compare, Eq, Hash, ToJson, @moonbitlang/core/debug.Debug
Debug)

One baggage entry together with its metadata payload. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#overview

KeyValueMetadata::new

source

fn KeyValueMetadata::new(key : StringView, value : StringView, metadata? : BaggageMetadata) -> KeyValueMetadata

Creates one baggage entry description.

This only packages the data. Validation happens when the entry is inserted into a Baggage. Spec: https://opentelemetry.io/docs/specs/otel/baggage/api/#set-value