Module dev 

bynk dev — build a project and serve it locally in one step.

Collapses the manual recipe (compile → cd into the generated worker dir → wrangler dev) into a single command (proposal v0.57). The orchestration is pre-flight → compile → select → serve, and almost every piece is reused: compiler::resolve for bynkc, the doctor Deploy capability for the Node + wrangler gate, and probe for locating wrangler with the same provenance ordering doctor reports.

The serve step runs wrangler dev in local mode (Miniflare), which simulates KV / Durable Objects / queues keyed by binding name — so no namespace provisioning is needed and the generated wrangler.toml is served untouched (proposal §1, D4). Everything wrangler-specific is encapsulated here so the serve step can later be swapped for a first-party workerd server without touching the rest (proposal §4).

Since #552 the step is one wrangler dev per context, not one per project: the processes discover each other through wrangler’s dev registry and wire the emitted [[services]] bindings between themselves, so a cross-context call resolves locally. That makes the driver a supervisor of N children rather than a hand-off to one — hence the port allocation (allocate), the joint teardown (terminate, private), and the plural selection rule (select_contexts) that replaced ADR 0096 D3’s ambiguity error.

Re-exports

pub use crate::workers::SelectError;

pub use crate::workers::compile_once;

pub use crate::workers::discover_workers;

pub use crate::workers::prepare_build_dir;

pub use crate::workers::select_contexts;

pub use crate::workers::wrangler_command;

Structs

DevOptions

Parsed bynk dev flags (the project PATH is resolved into project_root before we get here).

ServedContext

One served context in a DevEvent::Serving event.

Serving

One worker to serve: its dasherised context dir, its HTTP port (None = let wrangler choose, the lone-worker default), its inspector port, and whether the inspector was asked for (--inspect) rather than only allocated so the contexts’ default inspectors do not collide (#1954).

StandIn

Interop I5 (#1972): one stand-in bynk dev runs for a foreign Worker that a served context binds: the Worker’s name, and the context’s bindings to it. It runs inside that context’s own wrangler dev, as a second -c config, under a name of its own (stand_in_name).

Enums

DevEvent

One lifecycle event of a bynk dev --format json session (#2094): a stable, line-delimited interface for the editor and CI scripts, so neither has to parse the human report, whose wording is UX and changes. Serialised with an event tag in snake_case. A consumer should ignore fields and events it does not know: new ones may be added, existing ones keep their meaning.

DevFormat

bynk dev --format (#2094).

Constants

STAND_IN_CONFIG

The config a context with stand-ins is served from: its generated wrangler.toml with each binding to a foreign Worker pointed at the stand-in, beside the original so main resolves the same.

Functions

allocate

Allocate a port per worker (#552): wrangler dev binds one port per process, so serving N contexts means N distinct ports, assigned base + i over the deterministic worker order.

event_line

One event as its JSON line (no trailing newline).

foreign_services

Interop I5 (#1972): the Service Bindings in a generated wrangler.toml whose target is none of project_workers, as (binding, worker) in binding order: the bindings to foreign Workers, by the rule bynk deploy uses. An unreadable config has none; the serve step reports it.

needs_wrangler_warmup

#1957: whether to install wrangler once before spawning the contexts. Only an npx resolution installs on first use, and only several spawns at once race each other in npm’s _npx cache; a lone context installs alone.

preflight_failure_message

The text bynk dev prints when the deploy pre-flight fails: a lead line plus doctor’s own human report, so the remedy lines are identical to bynk doctor. Pure (no I/O) so this deterministic surface is pinned by a golden (§5), unlike the non-deterministic wrangler dev stream.

run

Orchestrate a local dev session: pre-flight, compile, select the worker, and hand off to wrangler dev. Returns wrangler’s own exit code on a clean hand-off, or a pre-flight/build failure code before serving.

serving_event

The DevEvent::Serving event for an allocation. A lone worker left on wrangler’s default (port: None) reports the port it actually gets: a -- --port N passthrough, else wrangler’s 8787.

serving_report

The start-up report: which context answers on which URL, plus the inspector notice under --inspect. Pure and deterministic, so it is golden-pinned in the style of ADR 0096 §Exit — unlike the wrangler dev streams it precedes.

stand_in_files

The stand-in’s wrangler.toml and index.js. It answers every request with bynk_emit::emitter::wrangler::FOREIGN_SERVICE_DOUBLE_STATUS and a body saying what it is and how to reach the real Worker, as the integration test harness’s stand-in does.

stand_in_name

The Worker name context‘s stand-in for worker runs under. Not the foreign Worker’s own: a -c config’s Worker also registers in wrangler’s dev registry, which every local wrangler dev shares (verified on 4.149.0), so under the real name it would answer other sessions’ bindings to that Worker and, once stopped, could leave a stale entry for --local-worker to connect to. The context’s binding is pointed at this name instead (point_at_stand_ins).

stand_in_report

The start-up lines naming each stand-in, so a 503 from one is never a mystery. Empty when there are none.

stand_ins

Interop I5 (#1972, track §11 Q8): the stand-ins one context’s wrangler dev runs, one per foreign Worker it binds, in Worker order, less those local names. Verified on wrangler 4.149.0: a second -c config’s Worker answers its primary’s binding to it, and without one a binding to a Worker that is not running answers 503 (“Worker … not found”).

wrangler_age_notice

#1732: the warning bynk dev prints before serving with a wrangler older than bynk_emit::WRANGLER_MIN. Its workerd refuses the pinned compatibility date outright, and wrangler’s own error says nothing about Bynk, so this names the cause and the fix first. A warning, not a refusal: the version is doctor’s judgement, and the wrangler itself has the last word. None when the wrangler is new enough, or can’t be versioned (npx).