Automatically handle shared credentials filename home directory expan…

…sion (#40)

Reference: #30

For consistency, adding the capability for the Terraform S3 Backend and allowing the Terraform AWS Provider to remove this code.

awsauth.go

@@ -20,6 +20,7 @@ import (
 	"github.com/aws/aws-sdk-go/service/sts"
 	"github.com/hashicorp/go-cleanhttp"
 	"github.com/hashicorp/go-multierror"
+	homedir "github.com/mitchellh/go-homedir"
 )
 
 const (
@@ -295,6 +296,12 @@ func GetCredentialsFromMetadata(c *Config) (*awsCredentials.Credentials, error)
 // GetCredentials also validates the credentials and the ability to assume a role
 // or will return an error if unsuccessful.
 func GetCredentials(c *Config) (*awsCredentials.Credentials, error) {
+	sharedCredentialsFilename, err := homedir.Expand(c.CredsFilename)
+
+	if err != nil {
+		return nil, fmt.Errorf("error expanding shared credentials filename: %w", err)
+	}
+
 	// build a chain provider, lazy-evaluated by aws-sdk
 	providers := []awsCredentials.Provider{
 		&awsCredentials.StaticProvider{Value: awsCredentials.Value{
@@ -304,7 +311,7 @@ func GetCredentials(c *Config) (*awsCredentials.Credentials, error) {
 		}},
 		&awsCredentials.EnvProvider{},
 		&awsCredentials.SharedCredentialsProvider{
-			Filename: c.CredsFilename,
+			Filename: sharedCredentialsFilename,
 			Profile:  c.Profile,
 		},
 	}

go.mod

@@ -4,6 +4,7 @@ require (
 	github.com/aws/aws-sdk-go v1.25.3
 	github.com/hashicorp/go-cleanhttp v0.5.0
 	github.com/hashicorp/go-multierror v1.0.0
+	github.com/mitchellh/go-homedir v1.1.0
 	github.com/stretchr/testify v1.3.0 // indirect
 	golang.org/x/net v0.0.0-20190213061140-3a22650c66bd // indirect
 	golang.org/x/text v0.3.0 // indirect

go.sum

@@ -10,6 +10,8 @@ github.com/hashicorp/go-multierror v1.0.0 h1:iVjPR7a6H0tWELX5NxNe7bYopibicUzc7uP
 github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHhCYQXV3UM06sGGrk=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af h1:pmfjZENx5imkbgOkpRUYLnmbU7UEFbjtDA2hxJ1ichM=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
+github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
+github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=