Struct StreamLayout 

pub struct StreamLayout { /* private fields */ }

Manages the on-disk directory layout for aggregate event streams.

The layout follows this structure:

<base_dir>/
    streams/
        <aggregate_type>/
            <instance_id>/      -- standard eventfold log directory
                app.jsonl
                views/
    projections/
        <projection_name>/
    meta/
        streams.jsonl           -- stream registry

StreamLayout is cheap to clone (it wraps a single PathBuf) and provides path helpers plus stream lifecycle management (creation and listing).

Implementations

impl StreamLayout

pub fn new(base_dir: impl Into<PathBuf>) -> Self

Create a new StreamLayout rooted at the given base directory.

Arguments

• base_dir - Root directory for all event store data. The directory does not need to exist yet; it will be created lazily when ensure_stream is called.

pub fn base_dir(&self) -> &Path

Returns the root directory of this layout.

pub fn stream_dir(&self, aggregate_type: &str, instance_id: &str) -> PathBuf

Returns the path to a specific aggregate instance’s stream directory.

Arguments

• aggregate_type - The aggregate type name (e.g. "order").
• instance_id - The unique instance identifier within that type.

Returns

<base_dir>/streams/<aggregate_type>/<instance_id>

pub fn views_dir(&self, aggregate_type: &str, instance_id: &str) -> PathBuf

Returns the path to a specific aggregate instance’s views directory.

Arguments

• aggregate_type - The aggregate type name (e.g. "order").
• instance_id - The unique instance identifier within that type.

Returns

<base_dir>/streams/<aggregate_type>/<instance_id>/views

pub fn projections_dir(&self) -> PathBuf

Returns the path to the projections directory.

Returns

<base_dir>/projections

pub fn process_managers_dir(&self) -> PathBuf

Returns the path to the process managers directory.

Returns

<base_dir>/process_managers

pub fn meta_dir(&self) -> PathBuf

Returns the path to the metadata directory.

Returns

<base_dir>/meta

pub fn ensure_stream( &self, aggregate_type: &str, instance_id: &str, ) -> Result<PathBuf>

Ensures that the stream directory and registry entry exist for the given aggregate type and instance ID.

This method is idempotent: calling it multiple times with the same arguments will not create duplicate directory trees or registry entries.

Arguments

• aggregate_type - The aggregate type name (e.g. "order").
• instance_id - The unique instance identifier within that type.

Returns

The stream directory path on success.

Errors

Returns std::io::Error if directory creation or file I/O fails.

pub fn list_streams(&self, aggregate_type: &str) -> Result<Vec<String>>

Lists all instance IDs for the given aggregate type.

Arguments

• aggregate_type - The aggregate type name to list instances for.

Returns

A sorted Vec<String> of instance IDs. Returns an empty vector if the aggregate type directory does not exist.

Errors

Returns std::io::Error if reading the directory fails for a reason other than the directory not existing.

Trait Implementations

impl Clone for StreamLayout

fn clone(&self) -> StreamLayout

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StreamLayout

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

Formats the value using the given formatter.