DO_NOT_RESOLVE_ADDR

Author: vfarcic

Dockerfile

@@ -20,6 +20,7 @@ ENV CERTS="" \
     CONNECTION_MODE="http-keep-alive" \
     DEBUG="false" \
     DEFAULT_PORTS="80,443:ssl" \
+    DO_NOT_RESOLVE_ADDR="true" \
     EXTRA_FRONTEND="" \
     LISTENER_ADDRESS="" \
     MODE="default" \

docs/blocking.md

@@ -30,7 +30,7 @@ chmod +x swarm-cluster.sh
 eval $(docker-machine env node-1)
 ```
 
-# Deploying Services
+## Deploying Services
 
 Now we're ready to deploy the services that form the proxy stack and the demo services.
 

docs/config.md

@@ -25,6 +25,7 @@ The following environment variables can be used to configure the *Docker Flow Pr
 |DEBUG_HTTP_FORMAT  |Logging format that will be used with HTTP requests. Please consult [Custom log format](https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#8.2.4) for more info about the available options.|
 |DEBUG_TCP_FORMAT   |Logging format that will be used with TCP requests. Please consult [Custom log format](https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#8.2.4) for more info about the available options.|
 |DEFAULT_PORTS      |The default ports used by the proxy. Multiple values can be separated with comma (`,`). If a port should be for SSL connections, append it with `:ssl`. Additional binding options can be added after a port. For example, `80 accept-proxy,443 accept-proxy:ssl` adds `accept-proxy` to the defalt binding options.<br>**Default value:** `80,443:ssl`|
+|DO_NOT_RESOLVE_ADDR|Whether not to resolve addresses. If set to `true`, the proxy will NOT fail if the service is not available.<br>**Default value:** `true`|
 |EXTRA_FRONTEND     |Value will be added to the default `frontend` configuration. Multiple lines should be separated with comma (*,*).|
 |EXTRA_GLOBAL       |Value will be added to the default `global` configuration. Multiple lines should be separated with comma (*,*).|
 |LISTENER_ADDRESS   |The address of the [Docker Flow: Swarm Listener](https://github.com/vfarcic/docker-flow-swarm-listener) used for automatic proxy configuration.<br>**Example:** swarm-listener|

proxy/ha_proxy.go

@@ -234,10 +234,7 @@ func (m HaProxy) getConfigData() configData {
 	if len(d.ExtraFrontend) > 0 {
 		d.ExtraFrontend = fmt.Sprintf("    %s", d.ExtraFrontend)
 	}
-	if value, err := strconv.ParseBool(os.Getenv("CHECK_RESOLVERS")); err == nil && value {
-		d.ExtraDefaults += `
-    default-server init-addr last,libc,none`
-	}
+	m.addDefaultServer(&d)
 	m.addCompression(&d)
 	m.addDebug(&d)
 
@@ -317,6 +314,15 @@ func (m *HaProxy) addCompression(data *configData) {
 	}
 }
 
+func (m *HaProxy) addDefaultServer(data *configData) {
+	checkResolvers, _ := strconv.ParseBool(os.Getenv("CHECK_RESOLVERS"))
+	doNotResolveAddr, _ := strconv.ParseBool(os.Getenv("DO_NOT_RESOLVE_ADDR"))
+	if checkResolvers || doNotResolveAddr {
+		data.ExtraDefaults += `
+    default-server init-addr last,libc,none`
+	}
+}
+
 func (m *HaProxy) addDebug(data *configData) {
 	if strings.EqualFold(getSecretOrEnvVar("DEBUG", ""), "true") {
 		data.ExtraGlobal += `

proxy/ha_proxy_test.go

@@ -382,6 +382,32 @@ func (s HaProxyTestSuite) Test_CreateConfigFromTemplates_AddsDefaultServer_WhenC
 	s.Equal(expectedData, actualData)
 }
 
+func (s HaProxyTestSuite) Test_CreateConfigFromTemplates_AddsDefaultServer_WhenDoNotResolveAddrIsSetToTrue() {
+	orig := os.Getenv("DO_NOT_RESOLVE_ADDR")
+	defer func() { os.Setenv("DO_NOT_RESOLVE_ADDR", orig) }()
+	os.Setenv("DO_NOT_RESOLVE_ADDR", "true")
+	var actualData string
+	tmpl := strings.Replace(
+		s.TemplateContent,
+		"balance roundrobin\n",
+		"balance roundrobin\n\n    default-server init-addr last,libc,none",
+		-1,
+	)
+	expectedData := fmt.Sprintf(
+		"%s%s",
+		tmpl,
+		s.ServicesContent,
+	)
+	writeFile = func(filename string, data []byte, perm os.FileMode) error {
+		actualData = string(data)
+		return nil
+	}
+
+	NewHaProxy(s.TemplatesPath, s.ConfigsPath).CreateConfigFromTemplates()
+
+	s.Equal(expectedData, actualData)
+}
+
 func (s HaProxyTestSuite) Test_CreateConfigFromTemplates_AddsCompressionAlgo_WhenSet() {
 	compressionAlgoOrig := os.Getenv("COMPRESSION_ALGO")
 	defer func() { os.Setenv("COMPRESSION_ALGO", compressionAlgoOrig) }()