Graceful exit, and slight restructuring

README.md

@@ -12,32 +12,8 @@ and placed in whatever directory you will run CFHA from.
 
 Example configuration file:
 
-```js
-{
-  "hosts": [ //an array of hosts to check
-    {
-      "host": "192.168.1.1", //the IP address of the host
-      "type": "http", //the type of check to run, can be either http or https
-      "options": {} //optional additional parameters to the check module
-    },
-    {
-      "host": "192.168.1.2",
-      "type": "https",
-      "options": {
-        "hostname": "lb-check-hostname" //this is the only currently supported parameter, and will be sent as the "host" header of an http(s) request
-      }
-    }
-  ],
-  "cloudflare": { //cloudflare configuration
-    "email": "cfemail@example.com",
-    "apiKey": "CF_API_KEY", //get this from your cloudflare profile
-    "domain": "example.com", //the domain in cloudflare you will be operating on
-    "name": "lb.example.com", //the full dns record you wish to edit
-    "ttl": "1" //1 is automatic, otherwise see the cloudflare documentation on TTL
-  },
-  "interval": 1 //how often (in seconds) to ping the server, note that this is a number, not a string
-}
-```
+(the configuration format is currently in flux, the example will be updated when it is stable. for now just look at `core/config` and build a json object to match `Config`)
+
 
 Limitations
 ===========

checks/http.go

@@ -8,14 +8,12 @@ import (
   "fmt"
 )
 
-func NewHttpChecker(config core.CheckCreateConfig) *HttpChecker {
-  checker := HttpChecker{
+func NewHttpChecker(config core.CheckCreateConfig) *core.GenericCheck {
+  return core.NewGenericCheck(&HttpChecker{
     &http.Client{},
     config,
     config.Host.Type + "://" + config.Host.Host + "/",
-  }
-  go checker.run()
-  return &checker
+  })
 }
 
 type HttpChecker struct {
@@ -24,16 +22,16 @@ type HttpChecker struct {
   endpoint string
 }
 
-func (this *HttpChecker) run() {
-  interval := time.Duration(this.config.Interval) * time.Second
-  log.Print(fmt.Sprintf("Starting: %v\n", this.config.Host))
-  for true {
-    this.config.Engine.Input<- core.Result{
-      this.config.Host.Host,
-      this.check(),
-    }
-    time.Sleep(interval)
+func (this *HttpChecker) Check() time.Duration {
+  this.config.Engine.Input<- core.Result{
+    this.config.Host.Host,
+    this.check(),
   }
+  return this.config.Interval
+}
+
+func (this *HttpChecker) Stop() bool {
+  return true
 }
 
 func (this *HttpChecker) check() core.Status {

core/check.go

@@ -9,3 +9,42 @@ type CheckCreateConfig struct {
   Interval time.Duration
   Host TargetConfig
 }
+
+type Check interface{
+  Check() time.Duration
+  Stop() bool
+}
+
+func NewGenericCheck(proxy Check) *GenericCheck {
+  check := &GenericCheck{
+    make(chan bool, 0),
+    make(chan bool, 0),
+    proxy,
+  }
+  go check.run()
+  return check
+}
+
+type GenericCheck struct {
+  killswitch chan bool
+  killresponse chan bool
+  proxy Check
+}
+
+func (this *GenericCheck) Stop() bool {
+  this.killswitch<- true
+  return <-this.killresponse
+}
+
+func (this *GenericCheck) run() {
+  timeout := time.NewTimer(0)
+  for true {
+    select {
+      case <-this.killswitch:
+        this.killresponse<- this.proxy.Stop()
+        return
+      case <-timeout.C:
+        timeout = time.NewTimer(this.proxy.Check())
+    }
+  }
+}

core/config.go

@@ -5,12 +5,12 @@ type Config struct {
 }
 
 type CheckConfig struct {
-  Interval uint16
-  Target TargetConfig
+  Targets []TargetConfig
   Reactions []ReactionConfig
 }
 
 type TargetConfig struct {
+  Interval uint16
   Type string
   Host string
   Options map[string]string

core/engine.go

@@ -8,15 +8,32 @@ import (
 type Engine struct {
   Input chan Result
   handlers []*GenericHandler
+  checks []*GenericCheck
   killswitch chan bool
+  killresponse chan bool
 }
 
 func NewEngine() *Engine {
-  return &Engine{
+  engine := &Engine{
     make(chan Result),
     make([]*GenericHandler, 0),
-    make(chan bool, 1),
+    make([]*GenericCheck, 0),
+    make(chan bool, 0),
+    make(chan bool, 0),
   }
+
+  go engine.startProcessor()
+
+  return engine
+}
+
+func (this *Engine) AddCheck(check *GenericCheck) {
+  if check == nil {
+    return
+  }
+
+  this.checks = append(this.checks, check)
+  log.Print(fmt.Sprintf("%v", this.checks))
 }
 
 func (this *Engine) AddHandler(handler *GenericHandler) {
@@ -28,33 +45,50 @@ func (this *Engine) AddHandler(handler *GenericHandler) {
   log.Print(fmt.Sprintf("%v", this.handlers))
 }
 
-func (this *Engine) Run() {
-  go this.startProcessor()
+func (this *Engine) Stop() bool {
+  this.killswitch<- true
+  return <-this.killresponse
 }
 
 func (this *Engine) startProcessor() {
   statuses := make(map[string]Status)
   for true {
-    result := <-this.Input
+    select {
+      case result := <-this.Input:
+        //No transition if we don't exist
+        if result.Status == statuses[result.RecordValue] {
+          continue
+        }
 
-    //No transition if we don't exist
-    if result.Status == statuses[result.RecordValue] {
-      continue
+        //Create a record with to, from
+        change := Transition{
+          result.Status,
+          statuses[result.RecordValue],
+          result.RecordValue,
+        }
+
+        //Send the record to everyone who cares
+        for _, relay := range this.handlers {
+          relay.Channel<- change
+        }
+
+        //And set our new status
+        statuses[result.RecordValue] = result.Status
+      case <-this.killswitch:
+        this.killresponse<- this.stop()
+        return
     }
-
-    //Create a record with to, from
-    change := Transition{
-      result.Status,
-      statuses[result.RecordValue],
-      result.RecordValue,
-    }
-
-    //Send the record to everyone who cares
-    for _, relay := range this.handlers {
-      relay.Channel<- change
-    }
-
-    //And set our new status
-    statuses[result.RecordValue] = result.Status
   }
 }
+
+func (this *Engine) stop() bool {
+  exitStatus := true
+  for _, handler := range this.handlers {
+    exitStatus = exitStatus && handler.Stop()
+  }
+  for _, check := range this.checks {
+    exitStatus = exitStatus && check.Stop()
+  }
+  return exitStatus
+}
+

core/handler.go

@@ -5,35 +5,42 @@ import (
 
 type Handler interface{
   Handle(transition Transition)
-}
-
-type GenericHandler struct {
-  Channel chan Transition
-  killswitch chan bool
-}
-
-func (this *GenericHandler) Stop() {
-  this.killswitch <- true
-}
-
-func (this *GenericHandler) run(proxy Handler) {
-  for true {
-    var transition Transition
-    select {
-      case <-this.killswitch:
-        return
-      case transition = <-this.Channel:
-        proxy.Handle(transition)
-    }
-
-  }
+  Stop() bool
 }
 
 func NewGenericHandler(input chan Transition, proxy Handler) *GenericHandler {
   handler := &GenericHandler{
     input,
-    make(chan bool, 1),
+    make(chan bool, 0),
+    make(chan bool, 0),
+    proxy,
   }
-  go handler.run(proxy)
+  go handler.run()
   return handler
 }
+
+type GenericHandler struct {
+  Channel chan Transition
+  killswitch chan bool
+  killresponse chan bool
+  proxy Handler
+}
+
+func (this *GenericHandler) Stop() bool {
+  this.killswitch<- true
+  return <-this.killresponse
+}
+
+func (this *GenericHandler) run() {
+  for true {
+    var transition Transition
+    select {
+      case <-this.killswitch:
+        this.killresponse<- this.proxy.Stop()
+        return
+      case transition = <-this.Channel:
+        this.proxy.Handle(transition)
+    }
+
+  }
+}

engine/check.go

@@ -1,19 +1,24 @@
 package engine
 
 import (
+  "log"
+  "fmt"
   "time"
   "../core"
   "../checks"
 )
 
-func createCheck(interval uint16, engine *core.Engine, host core.TargetConfig) {
+func createCheck(engine *core.Engine, host core.TargetConfig) *core.GenericCheck {
+  log.Print("createCheck called")
+  log.Print(fmt.Sprintf("creating a `%s`", host.Type))
   config := core.CheckCreateConfig{
     engine,
-    time.Duration(int64(interval)) * time.Second,
+    time.Duration(int64(host.Interval)) * time.Second,
     host,
   }
   switch host.Type {
     case "http", "https":
-      checks.NewHttpChecker(config)
+      return checks.NewHttpChecker(config)
   }
+  return nil
 }

engine/engine.go

@@ -11,7 +11,9 @@ func EngineFromConfig(config core.CheckConfig) *core.Engine {
     engine.AddHandler(createHandler(reaction))
   }
 
-  createCheck(config.Interval, engine, config.Target)
+  for _, target := range config.Targets {
+    engine.AddCheck(createCheck(engine, target))
+  }
 
   return engine
 }

handlers/cloudflare.go

@@ -43,6 +43,10 @@ func (this *cloudflareHandler) Handle(transition core.Transition) {
   }
 }
 
+func (this *cloudflareHandler) Stop() bool {
+  return true
+}
+
 func (this *cloudflareHandler) removeCloudflareRecord(recordValue string) bool {
   records, err := this.client.RetrieveRecordsByName(this.config.Options["Domain"], this.config.Options["Name"])
 

handlers/log.go

@@ -18,3 +18,7 @@ func (this *logHandler) Handle(transition core.Transition) {
     transition.RecordValue, transition.To,
     transition.To.String()))
 }
+
+func (this *logHandler) Stop() bool {
+  return true
+}

main.go

@@ -3,7 +3,10 @@ package main
 import (
   "log"
   "fmt"
+  "os"
+  "syscall"
   "io/ioutil"
+  "os/signal"
   "encoding/json"
   "./core"
   "./engine"
@@ -24,9 +27,13 @@ func main() {
     engines = append(engines, engine.EngineFromConfig(check))
   }
 
-  for _, engine := range engines {
-    engine.Run()
-  }
+  sigs := make(chan os.Signal, 1)
+  signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+  <-sigs
 
-  select{}
+  log.Print(fmt.Sprintf("Stopping."))
+  for _, engine := range engines {
+    engine.Stop()
+  }
+  log.Print("Exiting.")
 }