Struct SessionWriter 

pub struct SessionWriter { /* private fields */ }

Append-only writer for a single zig session log file.

Mirrors zag’s SessionLogWriter (zag-agent/src/session_log.rs:344). Every emit increments seq, stamps ts, serializes one JSON line, and flushes — so a tailer reading the file sees the event within one poll cycle.

Implementations

impl SessionWriter

pub fn create( workflow_name: &str, workflow_path: &str, prompt: Option<&str>, tier_count: usize, ) -> Result<Self, ZigError>

Create a new session: generate a UUID, ensure the project sessions dir, open the log file for append, emit ZigSessionStarted, and upsert both indexes.

pub fn session_id(&self) -> &str

The session id (UUID) for this writer.

pub fn log_path(&self) -> &Path

The on-disk log path.

pub fn tier_started( &self, tier_index: usize, step_names: Vec<String>, ) -> Result<(), ZigError>

pub fn step_started( &self, step_name: &str, tier_index: usize, zag_session_id: &str, zag_command: &str, model: Option<&str>, prompt_preview: &str, ) -> Result<(), ZigError>

pub fn step_output( &self, step_name: &str, stream: OutputStream, line: &str, ) -> Result<(), ZigError>

pub fn step_completed( &self, step_name: &str, exit_code: i32, duration_ms: u64, saved_vars: Vec<String>, ) -> Result<(), ZigError>

pub fn step_failed( &self, step_name: &str, exit_code: Option<i32>, attempt: u32, error: &str, ) -> Result<(), ZigError>

pub fn step_skipped( &self, step_name: &str, reason: &str, ) -> Result<(), ZigError>

pub fn heartbeat(&self) -> Result<(), ZigError>

pub fn ended( &self, status: SessionStatus, duration_ms: u64, ) -> Result<(), ZigError>

Emit ZigSessionEnded and stamp the indexes with ended_at/status.