caddyconfig: register adapters as Caddy modules (#3132)

* admin: Refactor /load endpoint out of caddy package

This eliminates the caddy package's dependency on the caddyconfig
package, which helps prevent import cycles.

* v2: adapter: register config adapters as Caddy modules

* v2: adapter: simplify adapter registration as adapters and modules

* v2: adapter: let RegisterAdapter be in charge of registering adapters as modules

* v2: adapter: remove underscrores placeholders

* v2: adapter: explicitly ignore the error of writing response of writing warnings back to client

* Implicitly wrap config adapters as modules

Co-authored-by: Matthew Holt <mholt@users.noreply.github.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/caddyconfig/configadapters.go b/caddyconfig/configadapters.go
index 071221f..96d7e10 100644
--- a/caddyconfig/configadapters.go
+++ b/caddyconfig/configadapters.go
@@ -17,6 +17,8 @@ package caddyconfig
 import (
 	"encoding/json"
 	"fmt"
+
+	"github.com/caddyserver/caddy/v2"
 )
 
 // Adapter is a type which can adapt a configuration to Caddy JSON.
@@ -105,7 +107,7 @@ func RegisterAdapter(name string, adapter Adapter) error {
 		return fmt.Errorf("%s: already registered", name)
 	}
 	configAdapters[name] = adapter
-	return nil
+	return caddy.RegisterModule(adapterModule{name, adapter})
 }
 
 // GetAdapter returns the adapter with the given name,
@@ -114,4 +116,21 @@ func GetAdapter(name string) Adapter {
 	return configAdapters[name]
 }
 
+// adapterModule is a wrapper type that can turn any config
+// adapter into a Caddy module, which has the benefit of being
+// counted with other modules, even though they do not
+// technically extend the Caddy configuration structure.
+// See caddyserver/caddy#3132.
+type adapterModule struct {
+	name string
+	Adapter
+}
+
+func (am adapterModule) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		ID:  caddy.ModuleID("caddy.adapters." + am.name),
+		New: func() caddy.Module { return am },
+	}
+}
+
 var configAdapters = make(map[string]Adapter)