PLT-6408 Framework for job server (#6404)

* Added initial job server

* Added job server to be ran as part of platform

* Added test job to the enterprise repo

* Fixed job server not loading license

* Renamed job package to jobs

* Fixed TE not being buildable

* Added JobStatus table to database

* Changed fields used by JobStatus

* Added APIs to query job status

* Added config change listener to server

* Added option to run job server from Makefile

* Added ability to enable/disable jobs from config

* Commented out placeholder for search indexing job

* Fixed govet

* Removed debug messages and fixed job api init message

3 files changed, 136 insertions, 0 deletions

diff --git a/utils/config.go b/utils/config.go
index 234acae11..95cfc43aa 100644
--- a/utils/config.go
+++ b/utils/config.go
@@ -50,6 +50,22 @@ func SetSiteURL(url string) {
 	siteURL = strings.TrimRight(url, "/")
 }
 
+var cfgListeners = map[string]func(*model.Config, *model.Config){}
+
+// Registers a function with a given to be called when the config is reloaded and may have changed. The function
+// will be called with two arguments: the old config and the new config. AddConfigListener returns a unique ID
+// for the listener that can later be used to remove it.
+func AddConfigListener(listener func(*model.Config, *model.Config)) string {
+	id := model.NewId()
+	cfgListeners[id] = listener
+	return id
+}
+
+// Removes a listener function by the unique ID returned when AddConfigListener was called
+func RemoveConfigListener(id string) {
+	delete(cfgListeners, id)
+}
+
 func FindConfigFile(fileName string) string {
 	if _, err := os.Stat("./config/" + fileName); err == nil {
 		fileName, _ = filepath.Abs("./config/" + fileName)
@@ -242,6 +258,21 @@ func DisableConfigWatch() {
 	}
 }
 
+func InitAndLoadConfig(filename string) (err string) {
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Sprintf("%v", r)
+		}
+	}()
+	TranslationsPreInit()
+	EnableConfigFromEnviromentVars()
+	LoadConfig(filename)
+	InitializeConfigWatch()
+	EnableConfigWatch()
+
+	return ""
+}
+
 // LoadConfig will try to search around for the corresponding config file.
 // It will search /tmp/fileName then attempt ./config/fileName,
 // then ../config/fileName and last it will look at fileName
@@ -249,6 +280,9 @@ func LoadConfig(fileName string) {
 	cfgMutex.Lock()
 	defer cfgMutex.Unlock()
 
+	// Cfg should never be null
+	oldConfig := *Cfg
+
 	fileNameWithExtension := filepath.Base(fileName)
 	fileExtension := filepath.Ext(fileNameWithExtension)
 	fileDir := filepath.Dir(fileName)
@@ -339,6 +373,10 @@ func LoadConfig(fileName string) {
 
 	SetDefaultRolesBasedOnConfig()
 	SetSiteURL(*Cfg.ServiceSettings.SiteURL)
+
+	for _, listener := range cfgListeners {
+		listener(&oldConfig, &config)
+	}
 }
 
 func RegenerateClientConfig() {
diff --git a/utils/config_test.go b/utils/config_test.go
index 755cd9acd..bce85d2ae 100644
--- a/utils/config_test.go
+++ b/utils/config_test.go
@@ -6,6 +6,8 @@ package utils
 import (
 	"os"
 	"testing"
+
+	"github.com/mattermost/platform/model"
 )
 
 func TestConfig(t *testing.T) {
@@ -59,3 +61,80 @@ func TestConfigFromEnviroVars(t *testing.T) {
 	}
 
 }
+
+func TestAddRemoveConfigListener(t *testing.T) {
+	if len(cfgListeners) != 0 {
+		t.Fatal("should've started with 0 listeners")
+	}
+
+	id1 := AddConfigListener(func(*model.Config, *model.Config) {
+	})
+	if len(cfgListeners) != 1 {
+		t.Fatal("should now have 1 listener")
+	}
+
+	id2 := AddConfigListener(func(*model.Config, *model.Config) {
+	})
+	if len(cfgListeners) != 2 {
+		t.Fatal("should now have 2 listeners")
+	}
+
+	RemoveConfigListener(id1)
+	if len(cfgListeners) != 1 {
+		t.Fatal("should've removed first listener")
+	}
+
+	RemoveConfigListener(id2)
+	if len(cfgListeners) != 0 {
+		t.Fatal("should've removed both listeners")
+	}
+}
+
+func TestConfigListener(t *testing.T) {
+	TranslationsPreInit()
+	EnableConfigFromEnviromentVars()
+	LoadConfig("config.json")
+
+	SiteName := Cfg.TeamSettings.SiteName
+	defer func() {
+		Cfg.TeamSettings.SiteName = SiteName
+		SaveConfig(CfgFileName, Cfg)
+	}()
+	Cfg.TeamSettings.SiteName = "test123"
+
+	listenerCalled := false
+	listener := func(oldConfig *model.Config, newConfig *model.Config) {
+		if listenerCalled {
+			t.Fatal("listener called twice")
+		}
+
+		if oldConfig.TeamSettings.SiteName != "test123" {
+			t.Fatal("old config contains incorrect site name")
+		} else if newConfig.TeamSettings.SiteName != "Mattermost" {
+			t.Fatal("new config contains incorrect site name")
+		}
+
+		listenerCalled = true
+	}
+	listenerId := AddConfigListener(listener)
+	defer RemoveConfigListener(listenerId)
+
+	listener2Called := false
+	listener2 := func(oldConfig *model.Config, newConfig *model.Config) {
+		if listener2Called {
+			t.Fatal("listener2 called twice")
+		}
+
+		listener2Called = true
+	}
+	listener2Id := AddConfigListener(listener2)
+	defer RemoveConfigListener(listener2Id)
+
+	LoadConfig("config.json")
+
+	if !listenerCalled {
+		t.Fatal("listener should've been called")
+	} else if !listener2Called {
+		t.Fatal("listener 2 should've been called")
+	}
+}
diff --git a/utils/license.go b/utils/license.go
index d3e2c1362..c0a17bf79 100644
--- a/utils/license.go
+++ b/utils/license.go
@@ -114,6 +114,25 @@ func ValidateLicense(signed []byte) (bool, string) {
 	return true, string(plaintext)
 }
 
+func GetAndValidateLicenseFileFromDisk() (*model.License, []byte) {
+	fileName := GetLicenseFileLocation(*Cfg.ServiceSettings.LicenseFileLocation)
+
+	if _, err := os.Stat(fileName); err != nil {
+		l4g.Debug("We could not find the license key in the database or on disk at %v", fileName)
+		return nil, nil
+	}
+
+	l4g.Info("License key has not been uploaded.  Loading license key from disk at %v", fileName)
+	licenseBytes := GetLicenseFileFromDisk(fileName)
+
+	if success, licenseStr := ValidateLicense(licenseBytes); !success {
+		l4g.Error("Found license key at %v but it appears to be invalid.", fileName)
+		return nil, nil
+	} else {
+		return model.LicenseFromJson(strings.NewReader(licenseStr)), licenseBytes
+	}
+}
+
 func GetLicenseFileFromDisk(fileName string) []byte {
 	file, err := os.Open(fileName)
 	if err != nil {