plugin-dns

Placement	compiled-in (in-process)
Source	github.com/opencharly/charly/candy/plugin-dns
Version	2026.176.1900
Candy	plugin-dns

This plugin is listed in charly/charly.yml’s compiled_plugins:, so its providers are compiled into the charly binary and register in-process.

Providers

The reserved words this plugin serves:

• dns — verb class

What it does

The dns check verb relocated into a candy: a name-resolution probe (in-container getent hosts under charly check box, host-side net.LookupIP under charly check live, with optional required-address matching). A HOST-COUPLED verb — its RunVerb runs against the live check engine (sdk/kit.CheckContext), so it is COMPILED-IN-ONLY. A pure check verb; a port/process-template relocation on the kit contract.

Parameter schema

The CUE schema below is the authoritative grammar for this plugin’s input. It is the same single source that generates the plugin’s Go parameter types and answers the runtime Describe RPC, so this page cannot disagree with either.

schema/dns.cue

// The BUILT-IN `dns` plugin's OWN CUE schema — the typed plugin_input for the `dns`
// verb (host-side `net.LookupIP` under live mode, in-container `getent hosts` under
// box mode). It is the SINGLE SOURCE for this plugin's params, used two ways (the same
// contract the reference examplerunverb and core `spec` use):
//
//  1. GENERATE the Go param struct — `cue exp gengotypes` (driven by task cue:gen,
//     which wraps this with `package params` + `@go(params)`) emits
//     ../params/cue_types_gen.go, so the provider decodes plugin_input into a TYPED
//     struct, never a hand-parsed map.
//  2. VALIDATE authored input AT RUNTIME — the builtin serves this source over the
//     Describe channel (InProcTransport) exactly like an external serves it over
//     gRPC; the host splices it onto the base (base ++ plugin) and validates every
//     authored `dns` step's plugin_input against #DnsInput.
//
// SELF-CONTAINED: it references NO base def, so it compiles standalone (gengotypes +
// the load-gate compile) AND splices onto the base — the base ++ plugin splice exists
// to detect a def-name collision with the base, not to resolve base refs.
//
// `addrs` is a SHARED base #Op field (the `interface` verb also reads it), so it STAYS
// in #Op; this plugin reproduces its `[...string]` shape standalone here (a bare
// primitive list, NO def reference, so there is no collision when base ++ plugin
// compiles). `server` is the dns verb's own (currently advisory) authoring field,
// preserved here verbatim so an authored `dns:`+`server:` step still validates. The
// (distinct) box/deploy `dns:` HOSTNAME field is a SEPARATE schema element
// (BoxMetadata.DNS) and is unaffected. The provider is a CheckVerbProvider — it
// dispatches IN-PROCESS via RunVerb (mirrors examplerunverb).
#DnsInput: {
  // dns — the hostname to resolve (the verb discriminator).
  dns: string @go(DNS)
  // resolvable — whether the hostname is expected to resolve (default true). A
  // tri-state pointer so an absent key means "expected resolvable".
  resolvable?: bool @go(Resolvable,type=*bool)
  // addrs — optional required resolved addresses; a resolved IP must match one.
  addrs?: [...string] @go(Addrs)
  // server — optional advisory resolver hint (preserved for authoring compatibility).
  server?: string @go(Server)
}

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See also the candy reference for this candy’s install surface.