caddyfile: Refactor unmarshaling of module tokens

Eliminates a fair amount of repeated code

1 files changed, 26 insertions, 0 deletions

diff --git a/caddyconfig/caddyfile/adapter.go b/caddyconfig/caddyfile/adapter.go
index 8d624f1..185816b 100644
--- a/caddyconfig/caddyfile/adapter.go
+++ b/caddyconfig/caddyfile/adapter.go
@@ -94,5 +94,31 @@ type ServerType interface {
 	Setup([]ServerBlock, map[string]interface{}) (*caddy.Config, []caddyconfig.Warning, error)
 }
 
+// UnmarshalModule instantiates a module with the given ID and invokes
+// UnmarshalCaddyfile on the new value using the immediate next segment
+// of d as input. In other words, d's next token should be the first
+// token of the module's Caddyfile input.
+//
+// This function is used when the next segment of Caddyfile tokens
+// belongs to another Caddy module. The returned value is often
+// type-asserted to the module's associated type for practical use
+// when setting up a config.
+func UnmarshalModule(d *Dispenser, moduleID string) (Unmarshaler, error) {
+	mod, err := caddy.GetModule(moduleID)
+	if err != nil {
+		return nil, d.Errf("getting module named '%s': %v", moduleID, err)
+	}
+	inst := mod.New()
+	unm, ok := inst.(Unmarshaler)
+	if !ok {
+		return nil, d.Errf("module %s is not a Caddyfile unmarshaler; is %T", mod.ID, inst)
+	}
+	err = unm.UnmarshalCaddyfile(d.NewFromNextSegment())
+	if err != nil {
+		return nil, err
+	}
+	return unm, nil
+}
+
 // Interface guard
 var _ caddyconfig.Adapter = (*Adapter)(nil)