lib/ovsdb-idl.h

   1 /* Copyright (c) 2009, 2010 Nicira Networks.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #ifndef OVSDB_IDL_H
  17 #define OVSDB_IDL_H 1
  18
  19 /* Open vSwitch Database Interface Definition Language (OVSDB IDL).
  20  *
  21  * The OVSDB IDL maintains an in-memory replica of a database.  It issues RPC
  22  * requests to an OVSDB database server and parses the responses, converting
  23  * raw JSON into data structures that are easier for clients to digest.  Most
  24  * notably, references to rows via UUID become C pointers.
  25  *
  26  * The IDL also assists with issuing database transactions.  The client creates
  27  * a transaction, manipulates the IDL data structures, and commits or aborts
  28  * the transaction.  The IDL then composes and issues the necessary JSON-RPC
  29  * requests and reports to the client whether the transaction completed
  30  * successfully.
  31  */
  32
  33 #include <stdbool.h>
  34 #include <stdint.h>
  35 #include "compiler.h"
  36 #include "ovsdb-types.h"
  37
  38 struct json;
  39 struct ovsdb_datum;
  40 struct ovsdb_idl_class;
  41 struct ovsdb_idl_column;
  42 struct ovsdb_idl_table_class;
  43 struct uuid;
  44
  45 struct ovsdb_idl *ovsdb_idl_create(const char *remote,
  46                                    const struct ovsdb_idl_class *,
  47                                    bool monitor_everything_by_default);
  48 void ovsdb_idl_destroy(struct ovsdb_idl *);
  49
  50 bool ovsdb_idl_run(struct ovsdb_idl *);
  51 void ovsdb_idl_wait(struct ovsdb_idl *);
  52
  53 unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl *);
  54 bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl *);
  55 void ovsdb_idl_force_reconnect(struct ovsdb_idl *);
  56 \f
  57 /* Choosing columns and tables to replicate. */
  58
  59 /* Modes with which the IDL can monitor a column.
  60  *
  61  * If no bits are set, the column is not monitored at all.  Its value will
  62  * always appear to the client to be the default value for its type.
  63  *
  64  * If OVSDB_IDL_MONITOR is set, then the column is replicated.  Its value will
  65  * reflect the value in the database.  If OVSDB_IDL_ALERT is also set, then
  66  * ovsdb_idl_run() will return "true", and the value returned by
  67  * ovsdb_idl_get_seqno() will change, when the column's value changes.
  68  *
  69  * The possible mode combinations are:
  70  *
  71  *   - 0, for a column that a client doesn't care about.
  72  *
  73  *   - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants
  74  *     to track and possibly update.
  75  *
  76  *   - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only",
  77  *     that is, it updates them but doesn't want to get alerted about its own
  78  *     updates.  It also won't be alerted about other clients' updates, so this
  79  *     is suitable only for use by a client that "owns" a particular column.
  80  *
  81  *   - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid.
  82  */
  83 #define OVSDB_IDL_MONITOR (1 << 0) /* Monitor this column? */
  84 #define OVSDB_IDL_ALERT   (1 << 1) /* Alert client when column updated? */
  85
  86 void ovsdb_idl_add_column(struct ovsdb_idl *, const struct ovsdb_idl_column *);
  87 void ovsdb_idl_add_table(struct ovsdb_idl *,
  88                          const struct ovsdb_idl_table_class *);
  89
  90 void ovsdb_idl_omit(struct ovsdb_idl *, const struct ovsdb_idl_column *);
  91 void ovsdb_idl_omit_alert(struct ovsdb_idl *, const struct ovsdb_idl_column *);
  92 \f
  93 /* Reading the database replica. */
  94
  95 const struct ovsdb_idl_row *ovsdb_idl_get_row_for_uuid(
  96     const struct ovsdb_idl *, const struct ovsdb_idl_table_class *,
  97     const struct uuid *);
  98 const struct ovsdb_idl_row *ovsdb_idl_first_row(
  99     const struct ovsdb_idl *, const struct ovsdb_idl_table_class *);
 100 const struct ovsdb_idl_row *ovsdb_idl_next_row(const struct ovsdb_idl_row *);
 101
 102 const struct ovsdb_datum *ovsdb_idl_read(const struct ovsdb_idl_row *,
 103                                          const struct ovsdb_idl_column *);
 104 const struct ovsdb_datum *ovsdb_idl_get(const struct ovsdb_idl_row *,
 105                                         const struct ovsdb_idl_column *,
 106                                         enum ovsdb_atomic_type key_type,
 107                                         enum ovsdb_atomic_type value_type);
 108 \f
 109 /* Transactions. */
 110
 111 enum ovsdb_idl_txn_status {
 112     TXN_UNCHANGED,              /* Transaction didn't include any changes. */
 113     TXN_INCOMPLETE,             /* Commit in progress, please wait. */
 114     TXN_ABORTED,                /* ovsdb_idl_txn_abort() called. */
 115     TXN_SUCCESS,                /* Commit successful. */
 116     TXN_TRY_AGAIN,              /* Commit failed because a "verify" operation
 117                                  * reported an inconsistency, due to a network
 118                                  * problem, or other transient failure. */
 119     TXN_ERROR                   /* Commit failed due to a hard error. */
 120 };
 121
 122 const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status);
 123
 124 struct ovsdb_idl_txn *ovsdb_idl_txn_create(struct ovsdb_idl *);
 125 void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn *, const char *, ...)
 126     PRINTF_FORMAT (2, 3);
 127 void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn *);
 128 void ovsdb_idl_txn_increment(struct ovsdb_idl_txn *, const char *table,
 129                              const char *column, const struct json *where);
 130 void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *);
 131 void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn *);
 132 enum ovsdb_idl_txn_status ovsdb_idl_txn_commit(struct ovsdb_idl_txn *);
 133 enum ovsdb_idl_txn_status ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn *);
 134 void ovsdb_idl_txn_abort(struct ovsdb_idl_txn *);
 135
 136 const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn *);
 137
 138 int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn *);
 139 const struct uuid *ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn *,
 140                                                  const struct uuid *);
 141
 142 void ovsdb_idl_txn_write(const struct ovsdb_idl_row *,
 143                          const struct ovsdb_idl_column *,
 144                          struct ovsdb_datum *);
 145 void ovsdb_idl_txn_delete(const struct ovsdb_idl_row *);
 146 const struct ovsdb_idl_row *ovsdb_idl_txn_insert(
 147     struct ovsdb_idl_txn *, const struct ovsdb_idl_table_class *,
 148     const struct uuid *);
 149
 150 struct ovsdb_idl *ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn *);
 151
 152 #endif /* ovsdb-idl.h */