Struct MessageBuilder 

pub struct MessageBuilder { /* private fields */ }

Builder for Message. Collapses the historical new / with_id / from_value / without_change_capture four-way constructor split into a single fluent shape.

use dataflow_rs::Message;
use serde_json::json;

// Minimal: serde_json payload, default UUID id, capture on.
let m = Message::builder()
    .payload_json(&json!({"order": {"total": 1500}}))
    .build();
assert!(m.id().len() > 0);
assert!(m.capture_changes());

Implementations

impl MessageBuilder

pub fn new() -> Self

Create an empty builder. Equivalent to MessageBuilder::default.

pub fn id(self, id: impl Into<String>) -> Self

Caller-supplied id (typically a correlation id from upstream). Defaults to a freshly-generated UUID v7.

pub fn payload(self, payload: Arc<OwnedDataValue>) -> Self

Already-owned payload Arc — zero serde_json walk, refcount-only share. Mutually exclusive with Self::payload_json; whichever is called last wins.

pub fn payload_json(self, payload: &JsonValue) -> Self

Construct the payload from a serde_json::Value. Goes through the OwnedDataValue::from(&Value) bridge (one deep walk).

pub fn data(self, data: OwnedDataValue) -> Self

Seed context.data.

Replaces the empty Object that Self::build would otherwise install; the other two root fields are unaffected. Seeding records no audit-trail entry and no Change — it is initial state, not a mutation.

Keys are taken literally: unlike crate::engine::utils::set_nested_value, a key containing . stays a single key and a leading # is not stripped.

A non-Object value is ignored, preserving the crate-wide invariant that the three root fields are always objects. Calling this twice keeps the last value.

use dataflow_rs::Message;
use serde_json::json;

let m = Message::builder().data_json(&json!({"order": {"total": 1500}})).build();
assert_eq!(m.data()["order"]["total"], json!(1500).into());

pub fn data_json(self, data: &JsonValue) -> Self

Self::data from a serde_json::Value (one OwnedDataValue::from deep walk).

pub fn metadata(self, metadata: OwnedDataValue) -> Self

Seed context.metadata — request headers, correlation ids, routing hints.

Engine::process_message adds processed_at and engine_version on top of whatever is seeded here; a seeded channel key is overwritten by process_message_for_channel. Same literal-key and non-object rules as Self::data.

use dataflow_rs::Message;
use serde_json::json;

let m = Message::builder().metadata_json(&json!({"source": "api"})).build();
assert_eq!(m.metadata()["source"], json!("api").into());

pub fn metadata_json(self, metadata: &JsonValue) -> Self

Self::metadata from a serde_json::Value.

pub fn temp_data(self, temp_data: OwnedDataValue) -> Self

Seed context.temp_data — scratch space for intermediate task output.

Same literal-key and non-object rules as Self::data.

use dataflow_rs::Message;
use serde_json::json;

let m = Message::builder().temp_data_json(&json!({"scratch": 1})).build();
assert_eq!(m.temp_data()["scratch"], json!(1).into());

pub fn temp_data_json(self, temp_data: &JsonValue) -> Self

Self::temp_data from a serde_json::Value.

pub fn routing_bucket(self, bucket: u8) -> Self

Routing bucket 0..=99 for crate::Workflow::rollout matching.

Values >= 100 are clamped to 99, keeping the builder infallible like the rest of its methods. A message with no bucket is admitted by every workflow, split or not.

use dataflow_rs::Message;

assert_eq!(Message::builder().routing_bucket(7).build().routing_bucket(), Some(7));
assert_eq!(Message::builder().routing_bucket(200).build().routing_bucket(), Some(99));
assert_eq!(Message::builder().build().routing_bucket(), None);

pub fn capture_changes(self, on: bool) -> Self

When false, built-in functions skip per-write Change capture — audit-trail entries are still recorded but their changes list is empty. Defaults to true.

pub fn build(self) -> Message

Finalize. Defaults: id = UUID v7, payload = OwnedDataValue::Null, capture_changes = true.

Trait Implementations

impl Default for MessageBuilder

fn default() -> MessageBuilder

Returns the “default value” for a type.