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Add a "status" endpoint for health checks #3

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Jul 22, 2016
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Add a "status" endpoint for health checks #3

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53 changes: 47 additions & 6 deletions ld-relay.go
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package main

import (
"encoding/json"
"errors"
"flag"
"fmt"
Expand All @@ -15,7 +16,6 @@ import (
"os"
"regexp"
"strings"
"sync"
"time"
)

Expand Down Expand Up @@ -45,10 +45,13 @@ type Config struct {
Environment map[string]*EnvConfig
}

type StatusEntry struct {
Status string `json:"status"`
}

var configFile string

func main() {
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I got rid of the wait group, which allows the server to start before all of the environments have been initialized. This makes the whole system a little more resilient-- it can begin serving requests if (e.g.) one environment can't connect.

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What will happen if a connection comes in for an environment that is not yet initialized?

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The corresponding client won't yet be in the handler map, so you'll get a 404.

var wg sync.WaitGroup

flag.StringVar(&configFile, "config", "/etc/ld-relay.conf", "configuration file location")

Expand All @@ -74,17 +77,23 @@ func main() {

handlers := cmap.New()

wg.Add(len(c.Environment))
clients := cmap.New()

for envName, _ := range c.Environment {
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This pre-seeds the map with all the configured environments.

clients.Set(envName, nil)
}

for envName, envConfig := range c.Environment {
go func(envName string, envConfig EnvConfig) {
defer wg.Done()
clientConfig := ld.DefaultConfig
clientConfig.Stream = true
clientConfig.FeatureStore = NewSSERelayFeatureStore(envConfig.ApiKey, publisher, c.Main.HeartbeatIntervalSecs)
clientConfig.StreamUri = c.Main.StreamUri
clientConfig.BaseUri = c.Main.BaseUri

_, err := ld.MakeCustomClient(envConfig.ApiKey, clientConfig, time.Second*10)
client, err := ld.MakeCustomClient(envConfig.ApiKey, clientConfig, time.Second*10)

clients.Set(envName, client)

if err != nil {
Error.Printf("Error initializing LaunchDarkly client for %s: %+v\n", envName, err)
Expand All @@ -101,7 +110,39 @@ func main() {
}(envName, *envConfig)
}

wg.Wait()
http.Handle("/status", http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
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Do we want to make the port configurable? i assume it will be listening on port 80 by default..

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It is-- this isn't where that's handled though. See where the configuration port is usdd

w.Header().Set("Content-Type", "application/json")
envs := make(map[string]StatusEntry)

healthy := true
for item := range clients.IterBuffered() {
if item.Val == nil {
envs[item.Key] = StatusEntry{Status: "disconnected"}
healthy = false
} else {
client := item.Val.(*ld.LDClient)
if client.Initialized() {
envs[item.Key] = StatusEntry{Status: "connected"}
} else {
envs[item.Key] = StatusEntry{Status: "disconnected"}
healthy = false
}
}
}

resp := make(map[string]interface{})

resp["environments"] = envs
if healthy {
resp["status"] = "healthy"
} else {
resp["status"] = "degraded"
}

data, _ := json.Marshal(resp)

w.Write(data)
}))

// Now make a single handler that dispatches to the appropriate handler based on the Authorization header
http.Handle("/features", http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
Expand Down