journal: add omap.go with go-ceph based omap manipulation funcs

These new omap manipulation functions (get/set/remove) are roughly
equivalent to the previous command-line based approach but rely
on direct api calls to ceph.

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

internal/journal/omap.go

@@ -0,0 +1,137 @@
+/*
+Copyright 2020 The Ceph-CSI Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package journal
+
+import (
+	"context"
+
+	"github.com/ceph/ceph-csi/internal/util"
+
+	"github.com/ceph/go-ceph/rados"
+	"k8s.io/klog"
+)
+
+func getOneOMapValue(
+	ctx context.Context,
+	conn *Connection,
+	poolName, namespace, oMapName, oMapKey string) (string, error) {
+	// fetch and configure the rados ioctx
+	ioctx, err := conn.conn.GetIoctx(poolName)
+	if err != nil {
+		return "", omapPoolError(poolName, err)
+	}
+	defer ioctx.Destroy()
+
+	if namespace != "" {
+		ioctx.SetNamespace(namespace)
+	}
+
+	pairs, err := ioctx.GetOmapValues(
+		oMapName, // oid (name of object)
+		"",       // startAfter (ignored)
+		oMapKey,  // filterPrefix - match only keys with this prefix
+		1,        // maxReturn - fetch no more than N values
+	)
+	switch err {
+	case nil:
+	case rados.ErrNotFound:
+		klog.Errorf(
+			util.Log(ctx, "omap not found (pool=%q, namespace=%q, name=%q, key=%q): %v"),
+			poolName, namespace, oMapName, oMapKey, err)
+		return "", util.NewErrKeyNotFound(oMapKey, err)
+	default:
+		return "", err
+	}
+
+	result, found := pairs[oMapKey]
+	if !found {
+		klog.Errorf(
+			util.Log(ctx, "key not found in omap (pool=%q, namespace=%q, name=%q, key=%q): %v"),
+			poolName, namespace, oMapName, oMapKey, err)
+		return "", util.NewErrKeyNotFound(oMapKey, nil)
+	}
+	klog.Infof(
+		util.Log(ctx, "XXX key found in omap! (pool=%q, namespace=%q, name=%q, key=%q): %v"),
+		poolName, namespace, oMapName, oMapKey, result)
+	return string(result), nil
+}
+
+func removeOneOMapKey(
+	ctx context.Context,
+	conn *Connection,
+	poolName, namespace, oMapName, oMapKey string) error {
+	// fetch and configure the rados ioctx
+	ioctx, err := conn.conn.GetIoctx(poolName)
+	if err != nil {
+		return omapPoolError(poolName, err)
+	}
+	defer ioctx.Destroy()
+
+	if namespace != "" {
+		ioctx.SetNamespace(namespace)
+	}
+
+	err = ioctx.RmOmapKeys(oMapName, []string{oMapKey})
+	if err != nil {
+		klog.Errorf(
+			util.Log(ctx, "failed removing omap key (pool=%q, namespace=%q, name=%q, key=%q): %v"),
+			poolName, namespace, oMapName, oMapKey, err)
+	} else {
+		klog.Infof(
+			util.Log(ctx, "XXX removed omap key (pool=%q, namespace=%q, name=%q, key=%q, ): %v"),
+			poolName, namespace, oMapName, oMapKey, err)
+	}
+	return err
+}
+
+func setOneOMapKey(
+	ctx context.Context,
+	conn *Connection,
+	poolName, namespace, oMapName, oMapKey, keyValue string) error {
+	// fetch and configure the rados ioctx
+	ioctx, err := conn.conn.GetIoctx(poolName)
+	if err != nil {
+		return omapPoolError(poolName, err)
+	}
+	defer ioctx.Destroy()
+
+	if namespace != "" {
+		ioctx.SetNamespace(namespace)
+	}
+
+	pairs := map[string][]byte{
+		oMapKey: []byte(keyValue),
+	}
+	err = ioctx.SetOmap(oMapName, pairs)
+	if err != nil {
+		klog.Errorf(
+			util.Log(ctx, "failed setting omap key (pool=%q, namespace=%q, name=%q, key=%q, value=%q): %v"),
+			poolName, namespace, oMapName, oMapKey, keyValue, err)
+	} else {
+		klog.Infof(
+			util.Log(ctx, "XXX set omap key (pool=%q, namespace=%q, name=%q, key=%q, value=%q): %v"),
+			poolName, namespace, oMapName, oMapKey, keyValue, err)
+	}
+	return err
+}
+
+func omapPoolError(poolName string, err error) error {
+	if err == rados.ErrNotFound {
+		return util.NewErrPoolNotFound(poolName, err)
+	}
+	return err
+}