Struct Metadata 

pub struct Metadata {
    pub correlation_id: Option<CorrelationId>,
    pub causation_id: Option<CausationId>,
    pub trace_id: Option<TraceId>,
    pub auth_principal: Option<Principal>,
    pub format: Option<FormatTag>,
    pub extensions: BTreeMap<String, Value>,
}

Key-value bag carried on every Message. Holds correlation id, causation id, trace id, auth principal, format hint, and arbitrary extension keys.

Fields

correlation_id: Option<CorrelationId>

Correlation id — links responses to requests.

causation_id: Option<CausationId>

Causation id — links events to the command that caused them.

trace_id: Option<TraceId>

Trace id for distributed tracing.

auth_principal: Option<Principal>

Auth principal.

format: Option<FormatTag>

Optional explicit format hint.

extensions: BTreeMap<String, Value>

Extension keys. BTreeMap for deterministic iteration and hash.

Implementations

impl Metadata

pub fn new() -> Self

Construct a Metadata with no named fields set and no extensions.

pub fn with_correlation(self, id: CorrelationId) -> Self

Set the correlation id.

pub fn with_causation(self, id: CausationId) -> Self

Set the causation id.

pub fn with_trace(self, id: TraceId) -> Self

Set the trace id.

pub fn with_extension<K: Into<String>, V: Into<Value>>( self, key: K, value: V, ) -> Self

Add an extension key-value pair. Extensions must not duplicate the named fields.

Trait Implementations

impl Clone for Metadata

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Metadata

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Metadata

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Metadata

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Metadata

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for Metadata

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Metadata