Caddyfile directives

Every directive of the switchboard handler block, with defaults.

The switchboard handler (module ID http.handlers.switchboard) accepts these directives inside its block. Every directive is optional except registry and channel in practice; see Caddy integration for working configs.

switchboard {
	registry s3 s3://rules/prod
	namespace customer-a
	channel prod
	poll_interval 2s
	fail_mode last_good
	fallback_fail_mode open
	invoke_timeout 50ms
	memory_limit 32mb
	max_action_bytes 64kb
	max_header_ops 32
	max_response_body 8kb
	cache_dir /var/lib/switchboard
	bootstrap_from_cache on
	pool_autoscale on
	pool_size 16
	min_pool_size 16
	max_pool_size 64
}

Registry and channel

Directive	Default	Description
`registry <kind> [url]`	—	Registry backend. `<kind>` is `s3`, `file`, or `https`; the optional URL (`s3://bucket/prefix`, `file:///path`, `https://host/base`) pins the location. With `s3` and no URL, the `SWITCHBOARD_S3_*` environment variables supply the endpoint and bucket.
`namespace`	—	Tenant namespace.
`channel`	`prod`	Channel to reconcile toward.
`poll_interval`	`2s`	How often the reconciler checks the channel pointer.

Failure policy

Directive	Default	Description
`fail_mode`	`open`	What happens when the rule is unavailable: `open`, `closed`, or `last_good`. See fail modes.
`fallback_fail_mode`	`open`	For `fail_mode last_good` only: `open` or `closed` after the last-good retry also fails.

Execution limits

All five are hard bounds enforced per invocation; violating actions are rejected, not clamped.

Directive	Default	Description
`invoke_timeout`	`50ms`	Preemptive deadline on guest execution.
`memory_limit`	`32mb`	Cap on guest linear memory.
`max_action_bytes`	`64kb`	Quota over all guest-produced strings.
`max_header_ops`	`32`	Request + response header operations combined.
`max_response_body`	`8kb`	Maximum `Respond` body size.

Cache

Directive	Default	Description
`cache_dir`	—	Directory for the durable last-known-good cache and wazero’s compilation cache.
`bootstrap_from_cache`	`on` when `cache_dir` is set	Activate the cached bundle at startup before touching the registry (`on`/`off`). Requires `cache_dir`.

Instance pool

Directive	Default	Description
`pool_autoscale`	`on`	Autoscale warm instances with load (`on`/`off`).
`pool_size`	`16`	Fixed pool size when autoscaling is off.
`min_pool_size`	`16`	Autoscale floor.
`max_pool_size`	`128`	Autoscale ceiling (must be ≥ `min_pool_size`).

JSON config

Every directive has a snake_case JSON counterpart under the handler object for native Caddy JSON configs, e.g. {"handler": "switchboard", "registry": "s3", "registry_url": "s3://rules/prod", "channel": "prod"}. The Go field names in engine.Config match one-to-one for embedded use.