add health manager component for all health-related things (#363)

sdk/config/config_test.go

@@ -20,11 +20,10 @@ import (
 	"os"
 	"testing"
 
-	"github.com/vapor-ware/synse-sdk/sdk/errors"
-	"github.com/vapor-ware/synse-sdk/sdk/policy"
-
 	"github.com/stretchr/testify/assert"
 	"github.com/vapor-ware/synse-sdk/internal/test"
+	"github.com/vapor-ware/synse-sdk/sdk/errors"
+	"github.com/vapor-ware/synse-sdk/sdk/policy"
 )
 
 func TestNewYamlLoader(t *testing.T) {

sdk/config/plugin.go

@@ -92,7 +92,8 @@ func (conf *Plugin) Log() {
 	log.Infof("  DynamicRegistration:")
 	log.Infof("    Config: %v", conf.DynamicRegistration.Config)
 	log.Infof("  Health:")
-	log.Infof("    HealthFile: %s", conf.Health.HealthFile)
+	log.Infof("    HealthFile:     %s", conf.Health.HealthFile)
+	log.Infof("    UpdateInterval: %s", conf.Health.UpdateInterval)
 	log.Infof("    Checks:")
 	log.Infof("      DisableDefaults: %v", conf.Health.Checks.DisableDefaults)
 }
@@ -295,6 +296,10 @@ type HealthSettings struct {
 	// "/etc/synse/plugin/healthy".
 	HealthFile string `default:"/etc/synse/plugin/healthy" yaml:"healthFile,omitempty"`
 
+	// UpdateInterval is the frequency with which the health file will be updated
+	// to designate the health status of the plugin.
+	UpdateInterval time.Duration `default:"30s" yaml:"updateInterval,omitempty"`
+
 	// Checks are the settings for plugin health checks.
 	Checks *HealthCheckSettings `default:"{}" yaml:"checks,omitempty"`
 }

sdk/health/checks.go

@@ -0,0 +1,29 @@
+// Synse SDK
+// Copyright (c) 2019 Vapor IO
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+package health
+
+// CheckType defines the type of a health Check.
+type CheckType string
+
+// Check is an interface which all health checks should implement.
+type Check interface {
+	GetName() string
+	GetType() CheckType
+	Status() *Status
+	Update()
+	Run()
+}

sdk/health/checks_test.go

@@ -0,0 +1,17 @@
+// Synse SDK
+// Copyright (c) 2019 Vapor IO
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+package health