- 🔥 Support Readiness checks (via `/ready`) status plugin endpoint.

Signed-off-by: Valery Piashchynski <[email protected]>

3 files changed, 93 insertions, 26 deletions

diff --git a/plugins/status/interface.go b/plugins/status/interface.go
index 0a92bc52..9d5a13af 100644
--- a/plugins/status/interface.go
+++ b/plugins/status/interface.go
@@ -9,3 +9,10 @@ type Status struct {
 type Checker interface {
 	Status() Status
 }
+
+// Readiness interface used to get readiness status from the plugin
+// that means, that worker poll inside the plugin has 1+ plugins which are ready to work
+// at the particular moment
+type Readiness interface {
+	Ready() Status
+}
diff --git a/plugins/status/plugin.go b/plugins/status/plugin.go
index 6fbe67cf..693440bf 100644
--- a/plugins/status/plugin.go
+++ b/plugins/status/plugin.go
@@ -18,10 +18,13 @@ const (
 )
 
 type Plugin struct {
-	registry map[string]Checker
-	server   *fiber.App
-	log      logger.Logger
-	cfg      *Config
+	// plugins which needs to be checked just as Status
+	statusRegistry map[string]Checker
+	// plugins which needs to send Readiness status
+	readyRegistry map[string]Readiness
+	server        *fiber.App
+	log           logger.Logger
+	cfg           *Config
 }
 
 func (c *Plugin) Init(log logger.Logger, cfg config.Configurer) error {
@@ -34,7 +37,9 @@ func (c *Plugin) Init(log logger.Logger, cfg config.Configurer) error {
 		return errors.E(op, errors.Disabled, err)
 	}
 
-	c.registry = make(map[string]Checker)
+	c.readyRegistry = make(map[string]Readiness)
+	c.statusRegistry = make(map[string]Checker)
+
 	c.log = log
 	return nil
 }
@@ -49,6 +54,7 @@ func (c *Plugin) Serve() chan error {
 	})
 
 	c.server.Use("/health", c.healthHandler)
+	c.server.Use("/ready", c.readinessHandler)
 
 	go func() {
 		err := c.server.Listen(c.cfg.Address)
@@ -69,10 +75,11 @@ func (c *Plugin) Stop() error {
 	return nil
 }
 
-// Reset named service.
-func (c *Plugin) Status(name string) (Status, error) {
+// status returns a Checker interface implementation
+// Reset named service. This is not an Status interface implementation
+func (c *Plugin) status(name string) (Status, error) {
 	const op = errors.Op("checker_plugin_status")
-	svc, ok := c.registry[name]
+	svc, ok := c.statusRegistry[name]
 	if !ok {
 		return Status{}, errors.E(op, errors.Errorf("no such service: %s", name))
 	}
@@ -80,16 +87,34 @@ func (c *Plugin) Status(name string) (Status, error) {
 	return svc.Status(), nil
 }
 
-// CollectTarget collecting services which can provide Status.
-func (c *Plugin) CollectTarget(name endure.Named, r Checker) error {
-	c.registry[name.Name()] = r
+// ready used to provide a readiness check for the plugin
+func (c *Plugin) ready(name string) (Status, error) {
+	const op = errors.Op("checker_plugin_ready")
+	svc, ok := c.readyRegistry[name]
+	if !ok {
+		return Status{}, errors.E(op, errors.Errorf("no such service: %s", name))
+	}
+
+	return svc.Ready(), nil
+}
+
+// CollectCheckerImpls collects services which can provide Status.
+func (c *Plugin) CollectCheckerImpls(name endure.Named, r Checker) error {
+	c.statusRegistry[name.Name()] = r
+	return nil
+}
+
+// CollectReadinessImpls collects services which can provide Readiness check.
+func (c *Plugin) CollectReadinessImpls(name endure.Named, r Readiness) error {
+	c.readyRegistry[name.Name()] = r
 	return nil
 }
 
 // Collects declares services to be collected.
 func (c *Plugin) Collects() []interface{} {
 	return []interface{}{
-		c.CollectTarget,
+		c.CollectReadinessImpls,
+		c.CollectCheckerImpls,
 	}
 }
 
@@ -109,6 +134,35 @@ type Plugins struct {
 
 const template string = "Service: %s: Status: %d\n"
 
+func (c *Plugin) readinessHandler(ctx *fiber.Ctx) error {
+	const op = errors.Op("checker_plugin_readiness_handler")
+	plugins := &Plugins{}
+	err := ctx.QueryParser(plugins)
+	if err != nil {
+		return errors.E(op, err)
+	}
+
+	if len(plugins.Plugins) == 0 {
+		ctx.Status(http.StatusOK)
+		_, _ = ctx.WriteString("No plugins provided in query. Query should be in form of: ready?plugin=plugin1&plugin=plugin2 \n")
+		return nil
+	}
+
+	// iterate over all provided plugins
+	for i := 0; i < len(plugins.Plugins); i++ {
+		// check if the plugin exists
+		if plugin, ok := c.readyRegistry[plugins.Plugins[i]]; ok {
+			st := plugin.Ready()
+			_, _ = ctx.WriteString(fmt.Sprintf(template, plugins.Plugins[i], st.Code))
+		} else {
+			_, _ = ctx.WriteString(fmt.Sprintf("Service: %s not found", plugins.Plugins[i]))
+		}
+	}
+
+	ctx.Status(http.StatusOK)
+	return nil
+}
+
 func (c *Plugin) healthHandler(ctx *fiber.Ctx) error {
 	const op = errors.Op("checker_plugin_health_handler")
 	plugins := &Plugins{}
@@ -123,26 +177,16 @@ func (c *Plugin) healthHandler(ctx *fiber.Ctx) error {
 		return nil
 	}
 
-	failed := false
 	// iterate over all provided plugins
 	for i := 0; i < len(plugins.Plugins); i++ {
 		// check if the plugin exists
-		if plugin, ok := c.registry[plugins.Plugins[i]]; ok {
+		if plugin, ok := c.statusRegistry[plugins.Plugins[i]]; ok {
 			st := plugin.Status()
-			if st.Code >= 500 {
-				failed = true
-				continue
-			} else if st.Code >= 100 && st.Code <= 400 {
-				_, _ = ctx.WriteString(fmt.Sprintf(template, plugins.Plugins[i], st.Code))
-			}
+			_, _ = ctx.WriteString(fmt.Sprintf(template, plugins.Plugins[i], st.Code))
 		} else {
 			_, _ = ctx.WriteString(fmt.Sprintf("Service: %s not found", plugins.Plugins[i]))
 		}
 	}
-	if failed {
-		ctx.Status(http.StatusInternalServerError)
-		return nil
-	}
 
 	ctx.Status(http.StatusOK)
 	return nil
diff --git a/plugins/status/rpc.go b/plugins/status/rpc.go
index 396ff451..755a06fa 100644
--- a/plugins/status/rpc.go
+++ b/plugins/status/rpc.go
@@ -14,7 +14,7 @@ type rpc struct {
 func (rpc *rpc) Status(service string, status *Status) error {
 	const op = errors.Op("checker_rpc_status")
 	rpc.log.Debug("started Status method", "service", service)
-	st, err := rpc.srv.Status(service)
+	st, err := rpc.srv.status(service)
 	if err != nil {
 		return errors.E(op, err)
 	}
@@ -22,6 +22,22 @@ func (rpc *rpc) Status(service string, status *Status) error {
 	*status = st
 
 	rpc.log.Debug("status code", "code", st.Code)
-	rpc.log.Debug("successfully finished Status method")
+	rpc.log.Debug("successfully finished the Status method")
+	return nil
+}
+
+// Status return current status of the provided plugin
+func (rpc *rpc) Ready(service string, status *Status) error {
+	const op = errors.Op("checker_rpc_ready")
+	rpc.log.Debug("started Ready method", "service", service)
+	st, err := rpc.srv.ready(service)
+	if err != nil {
+		return errors.E(op, err)
+	}
+
+	*status = st
+
+	rpc.log.Debug("status code", "code", st.Code)
+	rpc.log.Debug("successfully finished the Ready method")
 	return nil
 }