admin: Implement load_interval to pull config on a timer (#4246)

* feat: implement a simple timer to pull config

mostly referenced to the issue

re #4106

* Update admin.go

use `caddy.Duration`

Co-authored-by: Matt Holt <[email protected]>

* Update caddy.go

Co-authored-by: Matt Holt <[email protected]>

* Update admin.go

Co-authored-by: Francis Lavoie <[email protected]>

* fix: sync load config when no pull interval provided

try not to make break change

* fix: change PullInterval to LoadInterval

* fix: change pull_interval to load_interval

* Update caddy.go

Co-authored-by: Matt Holt <[email protected]>

Co-authored-by: Matt Holt <[email protected]>
Co-authored-by: Francis Lavoie <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/admin.go b/admin.go
index 8eef91653..ff5bc713c 100644
--- a/admin.go
+++ b/admin.go
@@ -109,6 +109,12 @@ type ConfigSettings struct {
 	//
 	// EXPERIMENTAL: Subject to change.
 	LoadRaw json.RawMessage `json:"load,omitempty" caddy:"namespace=caddy.config_loaders inline_key=module"`
+
+	// The interval to pull config. With a non-zero value, will pull config
+	// from config loader (eg. a http loader) with given interval.
+	//
+	// EXPERIMENTAL: Subject to change.
+	LoadInterval Duration `json:"load_interval,omitempty"`
 }
 
 // IdentityConfig configures management of this server's identity. An identity