Get compartment from metadata when not set in cfg

Fixes: #168

pkg/oci/client/client.go

@@ -28,6 +28,7 @@ import (
 	"k8s.io/client-go/tools/cache"
 
 	"github.com/golang/glog"
+	"github.com/oracle/oci-cloud-controller-manager/pkg/oci/instancemeta"
 	"github.com/oracle/oci-go-sdk/common"
 	"github.com/oracle/oci-go-sdk/core"
 	"github.com/oracle/oci-go-sdk/loadbalancer"
@@ -103,6 +104,15 @@ func New(config *Config) (Interface, error) {
 		subnetCache: cache.NewTTLStore(subnetCacheKeyFn, time.Duration(24)*time.Hour),
 	}
 
+	if config.Auth.CompartmentOCID == "" {
+		glog.Info("Compartment not supplied in config: attempting to infer from instance metadata")
+		metadata, err := instancemeta.New().Get()
+		if err != nil {
+			return nil, err
+		}
+		config.Auth.CompartmentOCID = metadata.CompartmentOCID
+	}
+
 	vcnID := config.VCNID
 	if vcnID == "" {
 		glog.Infof("No vcn provided in cloud provider config. Falling back to looking up VCN via LB subnet.")