Consider all Swarm resource envvars

This change extends the support for multiple envvars when
specifying swarm resources to consider ALL of the specified
environment variables instead of the first match.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/config/image/cuda_image.go

@@ -115,28 +115,35 @@ func (i CUDA) HasDisableRequire() bool {
 
 // DevicesFromEnvvars returns the devices requested by the image through environment variables
 func (i CUDA) DevicesFromEnvvars(envVars ...string) VisibleDevices {
-	// Grab a reference to devices from the first envvar
-	// in the list that actually exists in the environment.
-	var devices *string
+	// We concantenate all the devices from the specified envvars.
+	var isSet bool
+	var devices []string
+	requested := make(map[string]bool)
 	for _, envVar := range envVars {
 		if devs, ok := i[envVar]; ok {
-			devices = &devs
-			break
+			isSet = true
+			for _, d := range strings.Split(devs, ",") {
+				trimmed := strings.TrimSpace(d)
+				if len(trimmed) == 0 {
+					continue
+				}
+				devices = append(devices, trimmed)
+				requested[trimmed] = true
+			}
 		}
 	}
 
 	// Environment variable unset with legacy image: default to "all".
-	if devices == nil && i.IsLegacy() {
+	if !isSet && len(devices) == 0 && i.IsLegacy() {
 		return newVisibleDevices("all")
 	}
 
 	// Environment variable unset or empty or "void": return nil
-	if devices == nil || len(*devices) == 0 || *devices == "void" {
+	if len(devices) == 0 || requested["void"] {
 		return newVisibleDevices("void")
 	}
 
-	// Environment variable set to "none": reset to "".
-	return newVisibleDevices(*devices)
+	return newVisibleDevices(devices...)
 }
 
 // GetDriverCapabilities returns the requested driver capabilities.

internal/config/image/devices.go

@@ -33,18 +33,20 @@ var _ VisibleDevices = (*void)(nil)
 var _ VisibleDevices = (*devices)(nil)
 
 // newVisibleDevices creates a VisibleDevices based on the value of the specified envvar.
-func newVisibleDevices(envvar string) VisibleDevices {
-	if envvar == "all" {
-		return all{}
-	}
-	if envvar == "none" {
-		return none{}
-	}
-	if envvar == "" || envvar == "void" {
-		return void{}
+func newVisibleDevices(envvars ...string) VisibleDevices {
+	for _, envvar := range envvars {
+		if envvar == "all" {
+			return all{}
+		}
+		if envvar == "none" {
+			return none{}
+		}
+		if envvar == "" || envvar == "void" {
+			return void{}
+		}
 	}
 
-	return newDevices(envvar)
+	return newDevices(envvars...)
 }
 
 type all struct{}