DISTMYSQL-228: Orchestrator GUI messages should optionally

contain the name of the orchestratorapp generating the message

https://jira.percona.com/browse/DISTMYSQL-228

Problem:
When Orchestrator is used in HA setup it is not possible to know which
Orchestrator instance provided the response to the client. In general
it is OK however, for debugging purposes, it seems to be useful to be
able to easily identify the Orchestrator instance which serviced
the request.

Solution:
Two new configuration parameters were added
(if not present or empty strings, the old behavior applies)

PrependMessagesWithOrcIdentity:
FQDN - Fully qualified domain name of orchestrator's host will be added
with the fallback to 'hostname'
hostname - hostname of the orchestrator's host will be added with the
fallback to 'custom' if CustomOrcIdentity is not empty
custom - custom prefix as configured in CustomOrcIdentity will be added

CustomOrcIdentity:
Any string identifying Orchestrator instance. Works together with
PrependMessagesWithOrcIdentity=custom or as a fallback for
FQDN/hostname

Author: kamil-holubicki

go.mod

@@ -3,6 +3,7 @@ module github.com/openark/orchestrator
 go 1.16
 
 require (
+	github.com/Showmax/go-fqdn v1.0.0 // indirect
 	github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6
 	github.com/codegangsta/inject v0.0.0-20150114235600-33e0aa1cb7c0 // indirect
 	github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432
@@ -47,7 +48,7 @@ require (
 
 replace (
 	github.com/hashicorp/raft => github.com/openark/raft v0.0.0-20170918052300-fba9f909f7fe
+	github.com/openark/golib => ./go/golib
 	golang.org/x/text v0.3.0 => golang.org/x/text v0.3.8
 	golang.org/x/text v0.3.7 => golang.org/x/text v0.3.8
-	github.com/openark/golib => ./go/golib
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/Showmax/go-fqdn v1.0.0 h1:0rG5IbmVliNT5O19Mfuvna9LL7zlHyRfsSvBPZmF9tM=
+github.com/Showmax/go-fqdn v1.0.0/go.mod h1:SfrFBzmDCtCGrnHhoDjuvFnKsWjEQX/Q9ARZvOrJAko=
 github.com/armon/circbuf v0.0.0-20150827004946-bbbad097214e/go.mod h1:3U/XgcO3hCbHZ8TKRvWD2dDTCfh9M9ya+I9JpbB7O8o=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6 h1:G1bPvciwNyF7IUmKXNt9Ak3m6u9DE1rF+RmtIkBpVdA=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=

go/config/config.go

@@ -278,6 +278,8 @@ type Configuration struct {
 	EnforceExactSemiSyncReplicas               bool              // If true, semi-sync replicas will be enabled/disabled to match the wait count in the desired priority order; this applies to LockedSemiSyncMaster and MasterWithTooManySemiSyncReplicas
 	RecoverLockedSemiSyncMaster                bool              // If true, orchestrator will recover from a LockedSemiSync state by enabling semi-sync on replicas to match the wait count; this behavior can be overridden by EnforceExactSemiSyncReplicas
 	ReasonableLockedSemiSyncMasterSeconds      uint              // Time to evaluate the LockedSemiSyncHypothesis before triggering the LockedSemiSync analysis; falls back to ReasonableReplicationLagSeconds if not set
+	PrependMessagesWithOrcIdentity             string            // use FQDN/hostname/custom to prefix error message returned to the client. Empty string (default)/none skips prefixing.
+	CustomOrcIdentity                          string            // use if PrependMessagesWithOrcIdentity is 'custom'
 }
 
 // ToJSONString will marshal this configuration as JSON
@@ -452,6 +454,8 @@ func newConfiguration() *Configuration {
 		EnforceExactSemiSyncReplicas:               false,
 		RecoverLockedSemiSyncMaster:                false,
 		ReasonableLockedSemiSyncMasterSeconds:      0,
+		PrependMessagesWithOrcIdentity:             "",
+		CustomOrcIdentity:                          "",
 	}
 }
 

go/http/api.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -32,6 +33,7 @@ import (
 	"github.com/openark/golib/log"
 	"github.com/openark/golib/util"
 
+	fqdn "github.com/Showmax/go-fqdn"
 	"github.com/openark/orchestrator/go/agent"
 	"github.com/openark/orchestrator/go/collection"
 	"github.com/openark/orchestrator/go/config"
@@ -114,10 +116,52 @@ type APIResponse struct {
 	Details interface{}
 }
 
+var messagePrefix string
+
 func Respond(r render.Render, apiResponse *APIResponse) {
+	apiResponse.Message = fmt.Sprintf("%+v%+v", messagePrefix, apiResponse.Message)
 	r.JSON(apiResponse.Code.HttpStatus(), apiResponse)
 }
 
+func setupMessagePrefix() {
+	act := config.Config.PrependMessagesWithOrcIdentity
+	if act == "" || act == "none" {
+		return
+	}
+	if act != "FQDN" && act != "hostname" && act != "custom" {
+		log.Warning("PrependMessagesWithOrcIdentity option has unsupported value '%+v'")
+		return
+	}
+
+	var hostname string
+	var err error
+	fallbackActive := false
+
+	if act == "FQDN" {
+		if hostname, err = fqdn.FqdnHostname(); err != nil {
+			log.Warning("Failed to get Orchestrator's FQDN. Falling back to hostname.")
+			hostname = ""
+			fallbackActive = true
+		}
+	}
+	if fallbackActive || act == "hostname" {
+		fallbackActive = false
+		if hostname, err = os.Hostname(); err != nil {
+			log.Warning("Failed to get Orchestrator's FQDN. Falling back to custom prefix (if provided).")
+			hostname = ""
+			fallbackActive = true
+		}
+	}
+	if (fallbackActive || act == "custom") && config.Config.CustomOrcIdentity != "" {
+		hostname = config.Config.CustomOrcIdentity
+	}
+	if hostname != "" {
+		messagePrefix = fmt.Sprintf("Orchestrator %+v says: ", hostname)
+	} else {
+		log.Warning("Prepending messages with Orchestrator identity was requested, but identity cannot be determined. Skipping prefix.")
+	}
+}
+
 type HttpAPI struct {
 	URLPrefix string
 }
@@ -3963,4 +4007,6 @@ func (this *HttpAPI) RegisterRequests(m *martini.ClassicMartini) {
 	} else {
 		m.Get(config.Config.StatusEndpoint, this.StatusCheck)
 	}
+
+	setupMessagePrefix()
 }

vendor/modules.txt

@@ -1,3 +1,6 @@
+# github.com/Showmax/go-fqdn v1.0.0
+## explicit
+github.com/Showmax/go-fqdn
 # github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6
 ## explicit
 github.com/armon/consul-api
@@ -135,6 +138,6 @@ gopkg.in/gcfg.v1/types
 ## explicit
 gopkg.in/warnings.v0
 # github.com/hashicorp/raft => github.com/openark/raft v0.0.0-20170918052300-fba9f909f7fe
+# github.com/openark/golib => ./go/golib
 # golang.org/x/text v0.3.0 => golang.org/x/text v0.3.8
 # golang.org/x/text v0.3.7 => golang.org/x/text v0.3.8
-# github.com/openark/golib => ./go/golib