From d72456d188c42cf206e610ac821463ec752088b9 Mon Sep 17 00:00:00 2001
From: Pam Selle <pamela.selle@gmail.com>
Date: Wed, 27 Mar 2019 14:20:15 -0400
Subject: [PATCH] Add friendly error for when registry unresponsive

If the registry is unresponsive, you will now get an error
specific to this, rather than a misleading "provider unavailable" type
error. Also adds debug logging for when errors like this may occur
---
 command/init.go           |  8 ++++++++
 plugin/discovery/error.go |  4 ++++
 plugin/discovery/get.go   |  4 ++++
 registry/client.go        |  2 +-
 registry/errors.go        | 15 +++++++++++++++
 5 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/command/init.go b/command/init.go
index 6c5dd0a8e..c5438383a 100644
--- a/command/init.go
+++ b/command/init.go
@@ -504,6 +504,8 @@ func (c *InitCommand) getProviders(earlyConfig *earlyconfig.Config, state *state
 				}
 
 				switch {
+				case err == discovery.ErrorServiceUnreachable:
+					c.Ui.Error(errDiscoveryServiceUnreachable)
 				case err == discovery.ErrorNoSuchProvider:
 					c.Ui.Error(fmt.Sprintf(errProviderNotFound, provider, DefaultPluginVendorDir))
 				case err == discovery.ErrorNoSuitableVersion:
@@ -878,6 +880,12 @@ corresponding provider blocks in configuration, with the constraint strings
 suggested below.
 `
 
+const errDiscoveryServiceUnreachable = `
+[reset][bold][red]Registry service unreachable.[reset][red]
+
+This may indicate a network issue, or an issue with the requested Terraform Registry.
+`
+
 const errProviderNotFound = `
 [reset][bold][red]Provider %[1]q not available for installation.[reset][red]
 
diff --git a/plugin/discovery/error.go b/plugin/discovery/error.go
index c0b503067..b29d143a7 100644
--- a/plugin/discovery/error.go
+++ b/plugin/discovery/error.go
@@ -51,6 +51,10 @@ const ErrorChecksumVerification = Error("unexpected plugin checksum")
 // was not signed by any known key for the publisher
 const ErrorSignatureVerification = Error("unable to verify signature")
 
+// ErrorServiceUnreachable indicates that the network was unable to connect
+// to the registry service
+const ErrorServiceUnreachable = Error("registry service is unreachable")
+
 func (err Error) Error() string {
 	return string(err)
 }
diff --git a/plugin/discovery/get.go b/plugin/discovery/get.go
index cc8acee6c..f1fb85b33 100644
--- a/plugin/discovery/get.go
+++ b/plugin/discovery/get.go
@@ -125,6 +125,10 @@ func (i *ProviderInstaller) Get(provider string, req Constraints) (PluginMeta, t
 
 	// TODO: return multiple errors
 	if err != nil {
+		log.Printf("[DEBUG] %s", err)
+		if registry.IsServiceUnreachable(err) {
+			return PluginMeta{}, diags, ErrorServiceUnreachable
+		}
 		if registry.IsServiceNotProvided(err) {
 			return PluginMeta{}, diags, err
 		}
diff --git a/registry/client.go b/registry/client.go
index 0b90790d4..93424d176 100644
--- a/registry/client.go
+++ b/registry/client.go
@@ -62,7 +62,7 @@ func NewClient(services *disco.Disco, client *http.Client) *Client {
 func (c *Client) Discover(host svchost.Hostname, serviceID string) (*url.URL, error) {
 	service, err := c.services.DiscoverServiceURL(host, serviceID)
 	if err != nil {
-		return nil, err
+		return nil, &ServiceUnreachableError{err}
 	}
 	if !strings.HasSuffix(service.Path, "/") {
 		service.Path += "/"
diff --git a/registry/errors.go b/registry/errors.go
index cdde48221..5a6a31b08 100644
--- a/registry/errors.go
+++ b/registry/errors.go
@@ -46,3 +46,18 @@ func IsServiceNotProvided(err error) bool {
 	_, ok := err.(*disco.ErrServiceNotProvided)
 	return ok
 }
+
+// ServiceUnreachableError Registry service is unreachable
+type ServiceUnreachableError struct {
+	err error
+}
+
+func (e *ServiceUnreachableError) Error() string {
+	return e.err.Error()
+}
+
+// IsServiceUnreachable returns true if the registry/discovery service was unreachable
+func IsServiceUnreachable(err error) bool {
+	_, ok := err.(*ServiceUnreachableError)
+	return ok
+}