configuration reading.

Author: fractos

ConfigurationReader.go

@@ -0,0 +1,34 @@
+package warden
+
+import (
+    // "io"
+    // "fmt"
+    "encoding/json"
+    "io/ioutil"
+    "log"
+//    "time"
+//    "strconv"
+)
+
+type ConfigurationReader struct {
+    configFilename string
+}
+
+// New creates a new instance of the configuration reader for this passed filename
+func NewConfigurationReader(filename string) *ConfigurationReader {
+    return &ConfigurationReader{configFilename: filename}
+} // NewConfigurationReader
+
+func (configurationReader *ConfigurationReader) Read() *Configuration {
+    data, err := ioutil.ReadFile(configurationReader.configFilename)
+    if err != nil {
+        log.Fatal(err)
+    }
+    
+    var config *Configuration
+    if err:= json.Unmarshal(data, &config); err != nil {
+        return nil
+    }
+        
+    return config
+} // Read

FileServiceDescriptionReader.go

@@ -10,10 +10,12 @@ import (
 //    "strconv"
 )
 
+
 type FileServiceDescriptionReader struct {
     config string
 }
 
+// New creates a new instance of the service description reader for this passed filename
 func NewFileServiceDescriptionReader(config string) *FileServiceDescriptionReader {
     return &FileServiceDescriptionReader{config: config}
 } // NewFileServiceDescriptionReader

registrar.go

@@ -78,17 +78,4 @@ func (warden *Warden) getMatchingContainers(logger func(s string), containerName
         panic(err)
     }
     return []string { fmt.Sprintf("%s", out) }
-} // getMatchingContainers
-
-func (warden *Warden) availabilityZoneIsActive(logger func(s string), z string) bool {
-    // get list of active availability zones
-    activeZones := warden.getActiveAvailabilityZones(logger)
-    
-    for _, v := range activeZones {
-        if v == z {
-            return true
-        }
-    }
-    
-    return false
-} // availabilityZoneIsActive
+} // getMatchingContainers

types.go

@@ -20,4 +20,13 @@ type ServiceDescription struct {
 
 type ServiceDescriptionReader interface {
     Read() []*ServiceDescription
+}
+
+// Configuration holds the basic environment information for Warden including Redis details and the name of the service description file
+type Configuration struct {
+    ServiceManagementRedisAddress string `json:"serviceManagementRedisAddress"`
+    ServiceManagementRedisDatabaseNumber int64 `json:"serviceManagementRedisDatabaseNumber"`
+    NginxRedisAddress string `json:"nginxRedisAddress"`
+    NginxRedisDatabaseNumber int64 `json:"nginxRedisDatabaseNumber"`
+    ServiceDescriptionFilename string `json:"serviceDescriptionFilename"`
 }

warden.go

@@ -27,39 +27,39 @@ const ActivityPause = 300
 const ServiceManagerPause = 30
 const CandidateExpiry = 30
 
+func wardenLog(s string) {
+    fmt.Printf("warden: %s\n", s)
+} // WardenLog
+
 // Start will run both the registrar and manager co-routines.
 func (warden *Warden) Start() {
-    fmt.Println("Warden starting...")
+    wardenLog("starting...")
 
     // fetch some runtime constants:    
     //   get instance ID
     //   get current availability zone
-    warden.region, warden.availabilityZone, warden.instanceId = warden.getInstanceIdentity(func(s string) { fmt.Printf("warden: %s\n", s) })
-
-    panic(warden.instanceId)
-
-    serviceManagementRedisAddress := "localhost:6379"
-    var serviceManagementRedisDatabaseNumber int64 = 11
-    nginxRedisAddress := "localhost:6379"
-    var nginxRedisDatabaseNumber int64 = 15
+    warden.region, warden.availabilityZone, warden.instanceId = warden.getInstanceIdentity(wardenLog)
 
-    var serviceDescriptionReaderConfig = "services.json"
+    wardenLog(fmt.Sprintf("region is %s\navailability zone is %s\ninstance ID is %s", warden.region, warden.availabilityZone, warden.instanceId))
 
+    configReader := NewConfigurationReader("config.json")
+    configuration := configReader.Read()
+    
     var serviceDescriptionReader ServiceDescriptionReader
-    serviceDescriptionReader = NewFileServiceDescriptionReader(serviceDescriptionReaderConfig)
+    serviceDescriptionReader = NewFileServiceDescriptionReader(configuration.ServiceDescriptionFilename)
 
     warden.services = (serviceDescriptionReader).Read()
 
     warden.redisServiceManagement = redis.NewClient(&redis.Options{
-        Addr: serviceManagementRedisAddress,
+        Addr: configuration.ServiceManagementRedisAddress,
         Password: "",
-        DB: serviceManagementRedisDatabaseNumber,
+        DB: configuration.ServiceManagementRedisDatabaseNumber,
     })
 
     warden.redisLocal = redis.NewClient(&redis.Options{
-        Addr: nginxRedisAddress,
+        Addr: configuration.NginxRedisAddress,
         Password: "",
-        DB: nginxRedisDatabaseNumber,
+        DB: configuration.NginxRedisDatabaseNumber,
     })
 
     // start registrar coroutine
@@ -70,8 +70,6 @@ func (warden *Warden) Start() {
     fmt.Println("Warden finishing...")    
 } // main
 
-
-
 func (warden *Warden) ourAvailabilityZoneIsActive(logger func(s string)) bool {
     return warden.availabilityZoneIsActive(logger, warden.availabilityZone)
 } // ourAvailabilityZoneIsActive
@@ -103,28 +101,15 @@ func (warden *Warden) getInstanceIdentity(logger func(s string)) (string, string
     return doc.Region, doc.AvailabilityZone, doc.InstanceID
 } // getInstanceIdentity
 
-func (warden *Warden) getAvailabilityZone(logger func(s string)) string {
-    logger("getting availability zone")
-    m := ec2metadata.New(session.New())
-    doc, err := m.GetInstanceIdentityDocument()
-    if err != nil {
-        panic(err)
-    }
-    return doc.AvailabilityZone
-} // getAvailabilityZone
-
-func (warden *Warden) getInstanceId(logger func(s string)) string {
-    logger("getting instance Id")
+func (warden *Warden) availabilityZoneIsActive(logger func(s string), z string) bool {
+    // get list of active availability zones
+    activeZones := warden.getActiveAvailabilityZones(logger)
 
-    return "def1"
-} // getInstanceId
-
-func (warden *Warden) getRegion(logger func(s string)) string {
-    logger("getting region")
-    m := ec2metadata.New(session.New())
-    region, err := m.Region()
-    if err != nil {
-        panic(err)
+    for _, v := range activeZones {
+        if v == z {
+            return true
+        }
     }
-    return region 
-} // getRegion
+    
+    return false
+} // availabilityZoneIsActive