cephfs: add function ParseDefaultConfigEnv to set ceph config from env

Similar to the rados function of the same name, ParseDefaultConfigEnv
uses the environment to configure the cephfs mount.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

cephfs/cephfs.go

@@ -92,6 +92,19 @@ func (mount *MountInfo) ParseConfigArgv(argv []string) error {
 	return getError(ret)
 }
 
+// ParseDefaultConfigEnv configures the mount from the default Ceph
+// environment variable CEPH_ARGS.
+//
+// Implements:
+//  int ceph_conf_parse_env(struct ceph_mount_info *cmount, const char *var);
+func (mount *MountInfo) ParseDefaultConfigEnv() error {
+	if err := mount.validate(); err != nil {
+		return err
+	}
+	ret := C.ceph_conf_parse_env(mount.mount, nil)
+	return getError(ret)
+}
+
 // SetConfigOption sets the value of the configuration option identified by
 // the given name.
 //

cephfs/cephfs_test.go

@@ -299,6 +299,26 @@ func TestParseConfigArgv(t *testing.T) {
 	assert.Error(t, err)
 }
 
+func TestParseDefaultConfigEnv(t *testing.T) {
+	mount, err := CreateMount()
+	require.NoError(t, err)
+	require.NotNil(t, mount)
+	defer func() { assert.NoError(t, mount.Release()) }()
+
+	origVal, err := mount.GetConfigOption("log_file")
+	assert.NoError(t, err)
+
+	err = os.Setenv("CEPH_ARGS", "--log_file /dev/null")
+	assert.NoError(t, err)
+	err = mount.ParseDefaultConfigEnv()
+	assert.NoError(t, err)
+
+	currVal, err := mount.GetConfigOption("log_file")
+	assert.NoError(t, err)
+	assert.Equal(t, "/dev/null", currVal)
+	assert.NotEqual(t, "/dev/null", origVal)
+}
+
 func TestValidate(t *testing.T) {
 	mount, err := CreateMount()
 	assert.NoError(t, err)