1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
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:
7 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 /* Open vSwitch Database Interface Definition Language (OVSDB IDL).
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.
26 * The IDL always presents a consistent snapshot of the database to its client,
27 * that is, it won't present the effects of some part of a transaction applied
28 * at the database server without presenting all of its effects.
30 * The IDL also assists with issuing database transactions. The client creates
31 * a transaction, manipulates the IDL data structures, and commits or aborts
32 * the transaction. The IDL then composes and issues the necessary JSON-RPC
33 * requests and reports to the client whether the transaction completed
40 #include "ovsdb-types.h"
44 struct ovsdb_idl_class;
46 struct ovsdb_idl_column;
47 struct ovsdb_idl_table_class;
50 struct ovsdb_idl *ovsdb_idl_create(const char *remote,
51 const struct ovsdb_idl_class *,
52 bool monitor_everything_by_default,
54 void ovsdb_idl_destroy(struct ovsdb_idl *);
56 void ovsdb_idl_run(struct ovsdb_idl *);
57 void ovsdb_idl_wait(struct ovsdb_idl *);
59 void ovsdb_idl_set_lock(struct ovsdb_idl *, const char *lock_name);
60 bool ovsdb_idl_has_lock(const struct ovsdb_idl *);
61 bool ovsdb_idl_is_lock_contended(const struct ovsdb_idl *);
63 unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl *);
64 bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl *);
65 void ovsdb_idl_enable_reconnect(struct ovsdb_idl *);
66 void ovsdb_idl_force_reconnect(struct ovsdb_idl *);
67 void ovsdb_idl_verify_write_only(struct ovsdb_idl *);
69 bool ovsdb_idl_is_alive(const struct ovsdb_idl *);
70 int ovsdb_idl_get_last_error(const struct ovsdb_idl *);
72 /* Choosing columns and tables to replicate. */
74 /* Modes with which the IDL can monitor a column.
76 * If no bits are set, the column is not monitored at all. Its value will
77 * always appear to the client to be the default value for its type.
79 * If OVSDB_IDL_MONITOR is set, then the column is replicated. Its value will
80 * reflect the value in the database. If OVSDB_IDL_ALERT is also set, then the
81 * value returned by ovsdb_idl_get_seqno() will change when the column's value
84 * The possible mode combinations are:
86 * - 0, for a column that a client doesn't care about.
88 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants
89 * to track and possibly update.
91 * - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only",
92 * that is, it updates them but doesn't want to get alerted about its own
93 * updates. It also won't be alerted about other clients' updates, so this
94 * is suitable only for use by a client that "owns" a particular column.
96 * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid.
98 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT | OVSDB_IDL_TRACK), for a column
99 * that a client wants to track using the change tracking
100 * ovsdb_idl_track_get_*() functions.
102 #define OVSDB_IDL_MONITOR (1 << 0) /* Monitor this column? */
103 #define OVSDB_IDL_ALERT (1 << 1) /* Alert client when column updated? */
104 #define OVSDB_IDL_TRACK (1 << 2)
106 void ovsdb_idl_add_column(struct ovsdb_idl *, const struct ovsdb_idl_column *);
107 void ovsdb_idl_add_table(struct ovsdb_idl *,
108 const struct ovsdb_idl_table_class *);
110 void ovsdb_idl_omit(struct ovsdb_idl *, const struct ovsdb_idl_column *);
111 void ovsdb_idl_omit_alert(struct ovsdb_idl *, const struct ovsdb_idl_column *);
113 /* Change tracking. */
114 enum ovsdb_idl_change {
115 OVSDB_IDL_CHANGE_INSERT,
116 OVSDB_IDL_CHANGE_MODIFY,
117 OVSDB_IDL_CHANGE_DELETE,
121 /* Row, table sequence numbers */
122 unsigned int ovsdb_idl_table_get_seqno(
123 const struct ovsdb_idl *idl,
124 const struct ovsdb_idl_table_class *table_class);
125 unsigned int ovsdb_idl_row_get_seqno(
126 const struct ovsdb_idl_row *row,
127 enum ovsdb_idl_change change);
129 void ovsdb_idl_track_add_column(struct ovsdb_idl *idl,
130 const struct ovsdb_idl_column *column);
131 void ovsdb_idl_track_add_all(struct ovsdb_idl *idl);
132 const struct ovsdb_idl_row *ovsdb_idl_track_get_first(
133 const struct ovsdb_idl *, const struct ovsdb_idl_table_class *);
134 const struct ovsdb_idl_row *ovsdb_idl_track_get_next(const struct ovsdb_idl_row *);
135 void ovsdb_idl_track_clear(const struct ovsdb_idl *);
138 /* Reading the database replica. */
140 const struct ovsdb_idl_row *ovsdb_idl_get_row_for_uuid(
141 const struct ovsdb_idl *, const struct ovsdb_idl_table_class *,
142 const struct uuid *);
143 const struct ovsdb_idl_row *ovsdb_idl_first_row(
144 const struct ovsdb_idl *, const struct ovsdb_idl_table_class *);
145 const struct ovsdb_idl_row *ovsdb_idl_next_row(const struct ovsdb_idl_row *);
147 const struct ovsdb_datum *ovsdb_idl_read(const struct ovsdb_idl_row *,
148 const struct ovsdb_idl_column *);
149 const struct ovsdb_datum *ovsdb_idl_get(const struct ovsdb_idl_row *,
150 const struct ovsdb_idl_column *,
151 enum ovsdb_atomic_type key_type,
152 enum ovsdb_atomic_type value_type);
153 bool ovsdb_idl_is_mutable(const struct ovsdb_idl_row *,
154 const struct ovsdb_idl_column *);
156 bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row *);
160 * A transaction may modify the contents of a database by modifying the values
161 * of columns, deleting rows, inserting rows, or adding checks that columns in
162 * the database have not changed ("verify" operations), through
163 * ovsdb_idl_txn_*() functions. (The OVSDB IDL code generator produces helper
164 * functions that internally call the ovsdb_idl_txn_*() functions. These are
165 * likely to be more convenient.)
167 * Reading and writing columns and inserting and deleting rows are all
168 * straightforward. The reasons to verify columns are less obvious.
169 * Verification is the key to maintaining transactional integrity. Because
170 * OVSDB handles multiple clients, it can happen that between the time that
171 * OVSDB client A reads a column and writes a new value, OVSDB client B has
172 * written that column. Client A's write should not ordinarily overwrite
173 * client B's, especially if the column in question is a "map" column that
174 * contains several more or less independent data items. If client A adds a
175 * "verify" operation before it writes the column, then the transaction fails
176 * in case client B modifies it first. Client A will then see the new value of
177 * the column and compose a new transaction based on the new contents written
180 * When a transaction is complete, which must be before the next call to
181 * ovsdb_idl_run() on 'idl', call ovsdb_idl_txn_commit() or
182 * ovsdb_idl_txn_abort().
184 * The life-cycle of a transaction looks like this:
186 * 1. Create the transaction and record the initial sequence number:
188 * seqno = ovsdb_idl_get_seqno(idl);
189 * txn = ovsdb_idl_txn_create(idl);
191 * 2. Modify the database with ovsdb_idl_txn_*() functions directly or
194 * 3. Commit the transaction by calling ovsdb_idl_txn_commit(). The first call
195 * to this function probably returns TXN_INCOMPLETE. The client must keep
196 * calling again along as this remains true, calling ovsdb_idl_run() in
197 * between to let the IDL do protocol processing. (If the client doesn't
198 * have anything else to do in the meantime, it can use
199 * ovsdb_idl_txn_commit_block() to avoid having to loop itself.)
201 * 4. If the final status is TXN_TRY_AGAIN, wait for ovsdb_idl_get_seqno() to
202 * change from the saved 'seqno' (it's possible that it's already changed,
203 * in which case the client should not wait at all), then start over from
204 * step 1. Only a call to ovsdb_idl_run() will change the return value of
205 * ovsdb_idl_get_seqno(). (ovsdb_idl_txn_commit_block() calls
209 enum ovsdb_idl_txn_status {
210 TXN_UNCOMMITTED, /* Not yet committed or aborted. */
211 TXN_UNCHANGED, /* Transaction didn't include any changes. */
212 TXN_INCOMPLETE, /* Commit in progress, please wait. */
213 TXN_ABORTED, /* ovsdb_idl_txn_abort() called. */
214 TXN_SUCCESS, /* Commit successful. */
215 TXN_TRY_AGAIN, /* Commit failed because a "verify" operation
216 * reported an inconsistency, due to a network
217 * problem, or other transient failure. Wait
218 * for a change, then try again. */
219 TXN_NOT_LOCKED, /* Server hasn't given us the lock yet. */
220 TXN_ERROR /* Commit failed due to a hard error. */
223 const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status);
225 struct ovsdb_idl_txn *ovsdb_idl_txn_create(struct ovsdb_idl *);
226 void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn *, const char *, ...)
227 OVS_PRINTF_FORMAT (2, 3);
228 void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn *);
229 void ovsdb_idl_txn_increment(struct ovsdb_idl_txn *,
230 const struct ovsdb_idl_row *,
231 const struct ovsdb_idl_column *);
232 void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *);
233 void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn *);
234 enum ovsdb_idl_txn_status ovsdb_idl_txn_commit(struct ovsdb_idl_txn *);
235 enum ovsdb_idl_txn_status ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn *);
236 void ovsdb_idl_txn_abort(struct ovsdb_idl_txn *);
238 const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn *);
240 int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn *);
241 const struct uuid *ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn *,
242 const struct uuid *);
244 void ovsdb_idl_txn_write(const struct ovsdb_idl_row *,
245 const struct ovsdb_idl_column *,
246 struct ovsdb_datum *);
247 void ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row *,
248 const struct ovsdb_idl_column *,
249 const struct ovsdb_datum *);
250 void ovsdb_idl_txn_delete(const struct ovsdb_idl_row *);
251 const struct ovsdb_idl_row *ovsdb_idl_txn_insert(
252 struct ovsdb_idl_txn *, const struct ovsdb_idl_table_class *,
253 const struct uuid *);
255 struct ovsdb_idl *ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn *);
256 void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl *);
259 /* ovsdb_idl_loop provides an easy way to manage the transactions related
260 * to 'idl' and to cope with different status during transaction. */
261 struct ovsdb_idl_loop {
262 struct ovsdb_idl *idl;
263 unsigned int skip_seqno;
265 struct ovsdb_idl_txn *committing_txn;
266 unsigned int precommit_seqno;
268 struct ovsdb_idl_txn *open_txn;
271 #define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) }
273 void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop *);
274 struct ovsdb_idl_txn *ovsdb_idl_loop_run(struct ovsdb_idl_loop *);
275 void ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop *);
277 #endif /* ovsdb-idl.h */