Struct MessageMetadata

Source

pub struct MessageMetadata {
    pub timestamp: Option<Duration>,
    pub source: Option<Arc<str>>,
    pub partition: Option<u32>,
    pub offset: Option<u64>,
    pub key: Option<Arc<str>>,
    pub headers: Vec<(Arc<str>, Arc<str>)>,
}

Expand description

Metadata associated with a message.

Uses Arc<str> for string fields to enable zero-copy string sharing in fan-out scenarios and reduce memory usage for repeated strings.

Fields§

§timestamp: Option<Duration>

When the message was created (as Duration since UNIX_EPOCH).

§source: Option<Arc<str>>

The source of the message (e.g., topic, file, etc.). Uses Arc<str> for zero-copy string sharing.

§partition: Option<u32>

Partition or shard information.

§offset: Option<u64>

Offset within the partition/source.

§key: Option<Arc<str>>

User-defined key for routing/grouping. Uses Arc<str> for zero-copy string sharing.

§headers: Vec<(Arc<str>, Arc<str>)>

Additional headers/attributes. Uses Arc<str> for both keys and values to enable zero-copy sharing.

Implementations§

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impl MessageMetadata

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pub fn new() -> Self

Create new empty metadata.

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pub fn with_timestamp_now() -> Self

Create metadata with the current timestamp.

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pub fn timestamp(self, ts: Duration) -> Self

Set the timestamp.

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pub fn source(self, source: impl Into<Arc<str>>) -> Self

Set the source.

Accepts any type that can be converted to Arc<str>, including String, &str, and Arc<str>.

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pub fn partition(self, partition: u32) -> Self

Set the partition.

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pub fn offset(self, offset: u64) -> Self

Set the offset.

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pub fn key(self, key: impl Into<Arc<str>>) -> Self

Set the key.

Accepts any type that can be converted to Arc<str>, including String, &str, and Arc<str>.

Add a header.

Accepts any types that can be converted to Arc<str>, including String, &str, and Arc<str>.

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pub fn get_header(&self, name: &str) -> Option<&str>

Get a header by name.

Returns a &str reference to the header value if found.

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pub fn get_source(&self) -> Option<&str>

Get the source as a string reference.

Returns None if no source is set, or Some(&str) with the source value.

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pub fn get_key(&self) -> Option<&str>

Get the key as a string reference.

Returns None if no key is set, or Some(&str) with the key value.

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pub fn with_shared_source(self, source: Arc<str>) -> Self

Create metadata with shared source (for zero-copy scenarios).

This method accepts an Arc<str> for the source, enabling zero-copy sharing of source strings across multiple messages.

This is now equivalent to source() since MessageMetadata uses Arc<str> directly.

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pub fn with_shared_key(self, key: Arc<str>) -> Self

Create metadata with shared key (for zero-copy scenarios).

This method accepts an Arc<str> for the key, enabling zero-copy sharing of key strings across multiple messages.

This is now equivalent to key() since MessageMetadata uses Arc<str> directly.

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pub fn with_shared_header(self, name: Arc<str>, value: Arc<str>) -> Self

Add a header with shared strings (for zero-copy scenarios).

This method accepts Arc<str> for header name and value, enabling zero-copy sharing of header strings across multiple messages.

This is now equivalent to header() since MessageMetadata uses Arc<str> directly.

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pub fn with_source_borrowed(self, source: &str) -> Self

Create metadata with source from a borrowed string.

This is a convenience method that accepts &str and converts it to Arc<str>.

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pub fn with_source_interned<I: StringInternerTrait>( self, source: &str, interner: &I, ) -> Self

Create metadata with interned source string.

This method accepts a &str and a string interner, interns the string, and stores the interned Arc<str> as the source. This enables automatic string deduplication for repeated source values.

§Arguments

source - The source string to intern
interner - The string interner to use (must implement StringInternerTrait)

§Returns

Self for method chaining

§Note

This method accepts any type that implements StringInternerTrait, which is provided by streamweave-graph::StringInterner. For use with the graph package, pass a &StringInterner from streamweave-graph.

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pub fn with_key_interned<I: StringInternerTrait>( self, key: &str, interner: &I, ) -> Self

Create metadata with interned key string.

This method accepts a &str and a string interner, interns the string, and stores the interned Arc<str> as the key. This enables automatic string deduplication for repeated key values.

§Arguments

key - The key string to intern
interner - The string interner to use (must implement StringInternerTrait)

§Returns

Self for method chaining

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pub fn add_header_interned<I: StringInternerTrait>( self, name: &str, value: &str, interner: &I, ) -> Self

Add a header with interned strings.

This method accepts header name and value as &str, interns both strings, and adds the interned Arc<str> pair to headers. This enables automatic string deduplication for repeated header keys and values.