Emit useful error when kubernetes:config:kubeconfig fails to parse

Fixes #209.

CHANGELOG.md

@@ -1,5 +1,17 @@
 ## 0.25.3 (Unreleased)
 
+### Supported Kubernetes versions
+
+- v1.15.x
+- v1.14.x
+- v1.13.x
+
+### Bug fixes
+
+-   Emit a useful error message (rather than a useless one) if we fail to parse the YAML data in
+    `kubernetes:config:kubeconfig` (https://github.com/pulumi/pulumi-kubernetes/pull/636).
+
+
 ## 0.25.2 (July 11, 2019)
 
 ### Supported Kubernetes versions
@@ -10,7 +22,7 @@
 
 ### Improvements
 
--   The Kubernetes provider can now communicate detailed information about the difference between a resource's 
+-   The Kubernetes provider can now communicate detailed information about the difference between a resource's
 desired and actual state during a Pulumi update. (https://github.com/pulumi/pulumi-kubernetes/pull/618).
 -   Refactor Pod await logic for easier testing and maintenance (https://github.com/pulumi/pulumi-kubernetes/pull/590).
 -   Update to client-go v12.0.0 (https://github.com/pulumi/pulumi-kubernetes/pull/621).
@@ -72,7 +84,7 @@ desired and actual state during a Pulumi update. (https://github.com/pulumi/pulu
 
 BREAKING: This release changes the behavior of the provider `namespace` flag introduced
 in `0.23.0`. Previously, this flag was treated as an override, which ignored namespace
-values set directly on resources. Now, the flag is a default, and will only set the 
+values set directly on resources. Now, the flag is a default, and will only set the
 namespace if one is not already set. If you have created resources using a provider
 with the `namespace` flag set, this change may cause these resources to be recreated
 on the next update.

pkg/provider/provider.go

@@ -27,6 +27,7 @@ import (
 	"github.com/golang/glog"
 	pbempty "github.com/golang/protobuf/ptypes/empty"
 	structpb "github.com/golang/protobuf/ptypes/struct"
+	"github.com/pkg/errors"
 	pkgerrors "github.com/pkg/errors"
 	"github.com/pulumi/pulumi-kubernetes/pkg/await"
 	"github.com/pulumi/pulumi-kubernetes/pkg/clients"
@@ -234,7 +235,9 @@ func (k *kubeProvider) Configure(_ context.Context, req *pulumirpc.ConfigureRequ
 	if configJSON, ok := vars["kubernetes:config:kubeconfig"]; ok {
 		config, err := clientcmd.Load([]byte(configJSON))
 		if err != nil {
-			return nil, fmt.Errorf("failed to parse kubeconfig: %v", err)
+			return nil, pkgerrors.Wrap(err, "failed to parse kubeconfig data in "+
+				"`kubernetes:config:kubeconfig`; this must be a YAML literal string and not "+
+				"a filename or path")
 		}
 		kubeconfig = clientcmd.NewDefaultClientConfig(*config, overrides)
 	} else {