Fix Manta gateway client creation flow (#6425)

This commit fixes the Manta gateway client creation flow. We now affix
the endpoint scheme with endpoint URL while creating the Manta client
for gateway.

Also add steps in Manta gateway docs on how to run with custom Manta
endpoint.

Fixes #6408

cmd/gateway/manta/gateway-manta.go

@@ -117,12 +117,16 @@ EXAMPLES:
 }
 
 func mantaGatewayMain(ctx *cli.Context) {
+	args := ctx.Args()
+	if !ctx.Args().Present() {
+		args = cli.Args{"https://us-east.manta.joyent.com"}
+	}
+
 	// Validate gateway arguments.
-	host := ctx.Args().First()
-	// Validate gateway arguments.
-	logger.FatalIf(minio.ValidateGatewayArguments(ctx.GlobalString("address"), host), "Invalid argument")
+	logger.FatalIf(minio.ValidateGatewayArguments(ctx.GlobalString("address"), args.First()), "Invalid argument")
 
-	minio.StartGateway(ctx, &Manta{host})
+	// Start the gateway..
+	minio.StartGateway(ctx, &Manta{args.First()})
 }
 
 // Manta implements Gateway.
@@ -139,17 +143,22 @@ func (g *Manta) Name() string {
 // talk to manta remote backend.
 func (g *Manta) NewGatewayLayer(creds auth.Credentials) (minio.ObjectLayer, error) {
 	var err error
+	var secure bool
 	var signer authentication.Signer
 	var endpoint = defaultMantaURL
 	ctx := context.Background()
 
 	if g.host != "" {
-		endpoint, _, err = minio.ParseGatewayEndpoint(g.host)
+		endpoint, secure, err = minio.ParseGatewayEndpoint(g.host)
 		if err != nil {
 			return nil, err
 		}
+		if secure {
+			endpoint = "https://" + endpoint
+		} else {
+			endpoint = "http://" + endpoint
+		}
 	}
-
 	if overrideRoot, ok := os.LookupEnv("MANTA_ROOT"); ok {
 		mantaRoot = overrideRoot
 	}

docs/gateway/manta.md

@@ -20,6 +20,27 @@ export MANTA_KEY_MATERIAL=~/.ssh/id_rsa
 export MANTA_SUBUSER=devuser
 minio gateway manta
 ```
+
+## Run Minio Gateway for Manta Object Storage Custom Endpoints
+### Using Docker
+```
+docker run -p 9000:9000 --name manta-s3 \
+ -e "MINIO_ACCESS_KEY=joyentaccountname" \
+ -e "MINIO_SECRET_KEY=joyentkeyid" \
+ -e "MANTA_KEY_MATERIAL=~/.ssh/id_rsa" \
+ -e "MANTA_SUBUSER=devuser"
+ minio/minio gateway manta https://manta_service_endpoint:port
+```
+
+### Using Binary
+```
+export MINIO_ACCESS_KEY=joyentaccountname
+export MINIO_SECRET_KEY=joyentkeyid
+export MANTA_KEY_MATERIAL=~/.ssh/id_rsa
+export MANTA_SUBUSER=devuser
+minio gateway manta https://manta_service_endpoint:port
+```
+
 ## Test using Minio Browser
 Minio Gateway comes with an embedded web based object browser. Point your web browser to http://127.0.0.1:9000 to ensure that your server has started successfully.