X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=lib%2Fovsdb-idl.h;h=136c38cae2301652fa0c795229e4d6b6326499e1;hb=ca7e7bee86b4ee821d61b58bf15c89a9d8a3cb30;hp=cfbb97cc1d37d4b11d458e92a047cd474d51a8eb;hpb=af96ccd24690553a0f8e2dbe9ee72530f18629c6;p=cascardo%2Fovs.git diff --git a/lib/ovsdb-idl.h b/lib/ovsdb-idl.h index cfbb97cc1..136c38cae 100644 --- a/lib/ovsdb-idl.h +++ b/lib/ovsdb-idl.h @@ -1,4 +1,4 @@ -/* Copyright (c) 2009, 2010 Nicira Networks. +/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -16,26 +16,128 @@ #ifndef OVSDB_IDL_H #define OVSDB_IDL_H 1 +/* Open vSwitch Database Interface Definition Language (OVSDB IDL). + * + * The OVSDB IDL maintains an in-memory replica of a database. It issues RPC + * requests to an OVSDB database server and parses the responses, converting + * raw JSON into data structures that are easier for clients to digest. Most + * notably, references to rows via UUID become C pointers. + * + * The IDL always presents a consistent snapshot of the database to its client, + * that is, it won't present the effects of some part of a transaction applied + * at the database server without presenting all of its effects. + * + * The IDL also assists with issuing database transactions. The client creates + * a transaction, manipulates the IDL data structures, and commits or aborts + * the transaction. The IDL then composes and issues the necessary JSON-RPC + * requests and reports to the client whether the transaction completed + * successfully. + */ + #include #include +#include "compiler.h" +#include "ovsdb-types.h" struct json; struct ovsdb_datum; struct ovsdb_idl_class; +struct ovsdb_idl_row; struct ovsdb_idl_column; struct ovsdb_idl_table_class; struct uuid; struct ovsdb_idl *ovsdb_idl_create(const char *remote, - const struct ovsdb_idl_class *); + const struct ovsdb_idl_class *, + bool monitor_everything_by_default, + bool retry); void ovsdb_idl_destroy(struct ovsdb_idl *); void ovsdb_idl_run(struct ovsdb_idl *); void ovsdb_idl_wait(struct ovsdb_idl *); +void ovsdb_idl_set_lock(struct ovsdb_idl *, const char *lock_name); +bool ovsdb_idl_has_lock(const struct ovsdb_idl *); +bool ovsdb_idl_is_lock_contended(const struct ovsdb_idl *); + unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl *); bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl *); +void ovsdb_idl_enable_reconnect(struct ovsdb_idl *); void ovsdb_idl_force_reconnect(struct ovsdb_idl *); +void ovsdb_idl_verify_write_only(struct ovsdb_idl *); + +bool ovsdb_idl_is_alive(const struct ovsdb_idl *); +int ovsdb_idl_get_last_error(const struct ovsdb_idl *); + +/* Choosing columns and tables to replicate. */ + +/* Modes with which the IDL can monitor a column. + * + * If no bits are set, the column is not monitored at all. Its value will + * always appear to the client to be the default value for its type. + * + * If OVSDB_IDL_MONITOR is set, then the column is replicated. Its value will + * reflect the value in the database. If OVSDB_IDL_ALERT is also set, then the + * value returned by ovsdb_idl_get_seqno() will change when the column's value + * changes. + * + * The possible mode combinations are: + * + * - 0, for a column that a client doesn't care about. + * + * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants + * to track and possibly update. + * + * - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only", + * that is, it updates them but doesn't want to get alerted about its own + * updates. It also won't be alerted about other clients' updates, so this + * is suitable only for use by a client that "owns" a particular column. + * + * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid. + * + * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT | OVSDB_IDL_TRACK), for a column + * that a client wants to track using the change tracking + * ovsdb_idl_track_get_*() functions. + */ +#define OVSDB_IDL_MONITOR (1 << 0) /* Monitor this column? */ +#define OVSDB_IDL_ALERT (1 << 1) /* Alert client when column updated? */ +#define OVSDB_IDL_TRACK (1 << 2) + +void ovsdb_idl_add_column(struct ovsdb_idl *, const struct ovsdb_idl_column *); +void ovsdb_idl_add_table(struct ovsdb_idl *, + const struct ovsdb_idl_table_class *); + +void ovsdb_idl_omit(struct ovsdb_idl *, const struct ovsdb_idl_column *); +void ovsdb_idl_omit_alert(struct ovsdb_idl *, const struct ovsdb_idl_column *); + +/* Change tracking. */ +enum ovsdb_idl_change { + OVSDB_IDL_CHANGE_INSERT, + OVSDB_IDL_CHANGE_MODIFY, + OVSDB_IDL_CHANGE_DELETE, + OVSDB_IDL_CHANGE_MAX +}; + +/* Row, table sequence numbers */ +unsigned int ovsdb_idl_table_get_seqno( + const struct ovsdb_idl *idl, + const struct ovsdb_idl_table_class *table_class); +unsigned int ovsdb_idl_row_get_seqno( + const struct ovsdb_idl_row *row, + enum ovsdb_idl_change change); + +void ovsdb_idl_track_add_column(struct ovsdb_idl *idl, + const struct ovsdb_idl_column *column); +void ovsdb_idl_track_add_all(struct ovsdb_idl *idl); +const struct ovsdb_idl_row *ovsdb_idl_track_get_first( + const struct ovsdb_idl *, const struct ovsdb_idl_table_class *); +const struct ovsdb_idl_row *ovsdb_idl_track_get_next(const struct ovsdb_idl_row *); +bool ovsdb_idl_track_is_updated(const struct ovsdb_idl_row *row, + const struct ovsdb_idl_column *column); +void ovsdb_idl_track_clear(const struct ovsdb_idl *); + + +/* Reading the database replica. */ const struct ovsdb_idl_row *ovsdb_idl_get_row_for_uuid( const struct ovsdb_idl *, const struct ovsdb_idl_table_class *, @@ -44,24 +146,91 @@ const struct ovsdb_idl_row *ovsdb_idl_first_row( const struct ovsdb_idl *, const struct ovsdb_idl_table_class *); const struct ovsdb_idl_row *ovsdb_idl_next_row(const struct ovsdb_idl_row *); +const struct ovsdb_datum *ovsdb_idl_read(const struct ovsdb_idl_row *, + const struct ovsdb_idl_column *); +const struct ovsdb_datum *ovsdb_idl_get(const struct ovsdb_idl_row *, + const struct ovsdb_idl_column *, + enum ovsdb_atomic_type key_type, + enum ovsdb_atomic_type value_type); +bool ovsdb_idl_is_mutable(const struct ovsdb_idl_row *, + const struct ovsdb_idl_column *); + +bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row *); + +/* Transactions. + * + * A transaction may modify the contents of a database by modifying the values + * of columns, deleting rows, inserting rows, or adding checks that columns in + * the database have not changed ("verify" operations), through + * ovsdb_idl_txn_*() functions. (The OVSDB IDL code generator produces helper + * functions that internally call the ovsdb_idl_txn_*() functions. These are + * likely to be more convenient.) + * + * Reading and writing columns and inserting and deleting rows are all + * straightforward. The reasons to verify columns are less obvious. + * Verification is the key to maintaining transactional integrity. Because + * OVSDB handles multiple clients, it can happen that between the time that + * OVSDB client A reads a column and writes a new value, OVSDB client B has + * written that column. Client A's write should not ordinarily overwrite + * client B's, especially if the column in question is a "map" column that + * contains several more or less independent data items. If client A adds a + * "verify" operation before it writes the column, then the transaction fails + * in case client B modifies it first. Client A will then see the new value of + * the column and compose a new transaction based on the new contents written + * by client B. + * + * When a transaction is complete, which must be before the next call to + * ovsdb_idl_run() on 'idl', call ovsdb_idl_txn_commit() or + * ovsdb_idl_txn_abort(). + * + * The life-cycle of a transaction looks like this: + * + * 1. Create the transaction and record the initial sequence number: + * + * seqno = ovsdb_idl_get_seqno(idl); + * txn = ovsdb_idl_txn_create(idl); + * + * 2. Modify the database with ovsdb_idl_txn_*() functions directly or + * indirectly. + * + * 3. Commit the transaction by calling ovsdb_idl_txn_commit(). The first call + * to this function probably returns TXN_INCOMPLETE. The client must keep + * calling again along as this remains true, calling ovsdb_idl_run() in + * between to let the IDL do protocol processing. (If the client doesn't + * have anything else to do in the meantime, it can use + * ovsdb_idl_txn_commit_block() to avoid having to loop itself.) + * + * 4. If the final status is TXN_TRY_AGAIN, wait for ovsdb_idl_get_seqno() to + * change from the saved 'seqno' (it's possible that it's already changed, + * in which case the client should not wait at all), then start over from + * step 1. Only a call to ovsdb_idl_run() will change the return value of + * ovsdb_idl_get_seqno(). (ovsdb_idl_txn_commit_block() calls + * ovsdb_idl_run().) + */ + enum ovsdb_idl_txn_status { + TXN_UNCOMMITTED, /* Not yet committed or aborted. */ TXN_UNCHANGED, /* Transaction didn't include any changes. */ TXN_INCOMPLETE, /* Commit in progress, please wait. */ TXN_ABORTED, /* ovsdb_idl_txn_abort() called. */ TXN_SUCCESS, /* Commit successful. */ TXN_TRY_AGAIN, /* Commit failed because a "verify" operation * reported an inconsistency, due to a network - * problem, or other transient failure. */ + * problem, or other transient failure. Wait + * for a change, then try again. */ + TXN_NOT_LOCKED, /* Server hasn't given us the lock yet. */ TXN_ERROR /* Commit failed due to a hard error. */ }; const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status); struct ovsdb_idl_txn *ovsdb_idl_txn_create(struct ovsdb_idl *); -void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn *, const char *); +void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn *, const char *, ...) + OVS_PRINTF_FORMAT (2, 3); void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn *); -void ovsdb_idl_txn_increment(struct ovsdb_idl_txn *, const char *table, - const char *column, const struct json *where); +void ovsdb_idl_txn_increment(struct ovsdb_idl_txn *, + const struct ovsdb_idl_row *, + const struct ovsdb_idl_column *); void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *); void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn *); enum ovsdb_idl_txn_status ovsdb_idl_txn_commit(struct ovsdb_idl_txn *); @@ -74,14 +243,37 @@ int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn *); const struct uuid *ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn *, const struct uuid *); -void ovsdb_idl_txn_read(const struct ovsdb_idl_row *, - const struct ovsdb_idl_column *, - struct ovsdb_datum *); void ovsdb_idl_txn_write(const struct ovsdb_idl_row *, const struct ovsdb_idl_column *, struct ovsdb_datum *); +void ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row *, + const struct ovsdb_idl_column *, + const struct ovsdb_datum *); void ovsdb_idl_txn_delete(const struct ovsdb_idl_row *); const struct ovsdb_idl_row *ovsdb_idl_txn_insert( - struct ovsdb_idl_txn *, const struct ovsdb_idl_table_class *); + struct ovsdb_idl_txn *, const struct ovsdb_idl_table_class *, + const struct uuid *); + +struct ovsdb_idl *ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn *); +void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl *); + + +/* ovsdb_idl_loop provides an easy way to manage the transactions related + * to 'idl' and to cope with different status during transaction. */ +struct ovsdb_idl_loop { + struct ovsdb_idl *idl; + unsigned int skip_seqno; + + struct ovsdb_idl_txn *committing_txn; + unsigned int precommit_seqno; + + struct ovsdb_idl_txn *open_txn; +}; + +#define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) } + +void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop *); +struct ovsdb_idl_txn *ovsdb_idl_loop_run(struct ovsdb_idl_loop *); +void ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop *); #endif /* ovsdb-idl.h */