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ovsdb-idl: New function ovsdb_idl_create_unconnected().
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This new function makes it possible to create an instance of the IDL
without connecting it to a remote OVSDB server.  The caller can then
connect and disconnect using ovsdb_idl_set_remote(); the ability to
disconnect is a new feature.

With this patch, the ovsdb_idl 'session' member can be null whereas
previously it was always nonnull.  The scattered changes throughout
ovsdb-idl are to cope with this new possibility.

An upcoming patch will introduce the first user of this new feature.

Signed-off-by: Ben Pfaff <blp@ovn.org>
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@blp
blp committed Oct 4, 2018
1 parent bc9bbc4 commit 5e07b8f
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Showing 2 changed files with 88 additions and 32 deletions.
118 changes: 86 additions & 32 deletions lib/ovsdb-idl.c
View file
Expand Up @@ -233,6 +233,7 @@ struct ovsdb_idl {
* function currently returns then the session has reconnected and the
* state machine must restart. */
struct jsonrpc_session *session; /* Connection to the server. */
char *remote; /* 'session' remote name. */
enum ovsdb_idl_state state; /* Current session state. */
unsigned int state_seqno; /* See above. */
struct json *request_id; /* JSON ID for request awaiting reply. */
Expand Down Expand Up @@ -365,18 +366,6 @@ static void ovsdb_idl_destroy_indexes(struct ovsdb_idl_table *);
static void ovsdb_idl_add_to_indexes(const struct ovsdb_idl_row *);
static void ovsdb_idl_remove_from_indexes(const struct ovsdb_idl_row *);

static void
ovsdb_idl_open_session(struct ovsdb_idl *idl, const char *remote, bool retry)
{
ovs_assert(!idl->data.txn);
jsonrpc_session_close(idl->session);

struct svec remotes = SVEC_EMPTY_INITIALIZER;
ovsdb_session_parse_remote(remote, &remotes, &idl->cid);
idl->session = jsonrpc_session_open_multiple(&remotes, retry);
svec_destroy(&remotes);
}

static void
ovsdb_idl_db_init(struct ovsdb_idl_db *db, const struct ovsdb_idl_class *class,
struct ovsdb_idl *parent, bool monitor_everything_by_default)
Expand Down Expand Up @@ -443,13 +432,38 @@ ovsdb_idl_db_init(struct ovsdb_idl_db *db, const struct ovsdb_idl_class *class,
struct ovsdb_idl *
ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class,
bool monitor_everything_by_default, bool retry)
{
struct ovsdb_idl *idl = ovsdb_idl_create_unconnected(
class, monitor_everything_by_default);
ovsdb_idl_set_remote(idl, remote, retry);
return idl;
}

/* Creates and returns a connection to an in-memory replica of the remote
* database whose schema is described by 'class'. (Ordinarily 'class' is
* compiled from an OVSDB schema automatically by ovsdb-idlc.)
*
* Use ovsdb_idl_set_remote() to configure the database to which to connect.
* Until a remote is configured, no data can be retrieved.
*
* If 'monitor_everything_by_default' is true, then everything in the remote
* database will be replicated by default. ovsdb_idl_omit() and
* ovsdb_idl_omit_alert() may be used to selectively drop some columns from
* monitoring.
*
* If 'monitor_everything_by_default' is false, then no columns or tables will
* be replicated by default. ovsdb_idl_add_column() and ovsdb_idl_add_table()
* must be used to choose some columns or tables to replicate.
*/
struct ovsdb_idl *
ovsdb_idl_create_unconnected(const struct ovsdb_idl_class *class,
bool monitor_everything_by_default)
{
struct ovsdb_idl *idl;

idl = xzalloc(sizeof *idl);
ovsdb_idl_db_init(&idl->server, &serverrec_idl_class, idl, true);
ovsdb_idl_db_init(&idl->data, class, idl, monitor_everything_by_default);
ovsdb_idl_open_session(idl, remote, retry);
idl->state_seqno = UINT_MAX;
idl->request_id = NULL;
idl->leader_only = true;
Expand All @@ -471,14 +485,38 @@ ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class,
return idl;
}

/* Changes the remote and creates a new session. */
/* Changes the remote and creates a new session.
*
* If 'retry' is true, the connection to the remote will automatically retry
* when it fails. If 'retry' is false, the connection is one-time. */
void
ovsdb_idl_set_remote(struct ovsdb_idl *idl, const char *remote,
bool retry)
ovsdb_idl_set_remote(struct ovsdb_idl *idl, const char *remote, bool retry)
{
if (idl) {
ovsdb_idl_open_session(idl, remote, retry);
idl->state_seqno = UINT_MAX;
if (idl
&& ((remote != NULL) != (idl->remote != NULL)
|| (remote && idl->remote && strcmp(remote, idl->remote)))) {
ovs_assert(!idl->data.txn);

/* Close the old session, if any. */
if (idl->session) {
jsonrpc_session_close(idl->session);
idl->session = NULL;

free(idl->remote);
idl->remote = NULL;
}

/* Open new session, if any. */
if (remote) {
struct svec remotes = SVEC_EMPTY_INITIALIZER;
ovsdb_session_parse_remote(remote, &remotes, &idl->cid);
idl->session = jsonrpc_session_open_multiple(&remotes, retry);
svec_destroy(&remotes);

idl->state_seqno = UINT_MAX;

idl->remote = xstrdup(remote);
}
}
}

Expand Down Expand Up @@ -584,7 +622,7 @@ ovsdb_idl_state_to_string(enum ovsdb_idl_state state)
static void
ovsdb_idl_retry_at(struct ovsdb_idl *idl, const char *where)
{
if (jsonrpc_session_get_n_remotes(idl->session) > 1) {
if (idl->session && jsonrpc_session_get_n_remotes(idl->session) > 1) {
ovsdb_idl_force_reconnect(idl);
ovsdb_idl_transition_at(idl, IDL_S_RETRY, where);
} else {
Expand All @@ -597,7 +635,7 @@ ovsdb_idl_transition_at(struct ovsdb_idl *idl, enum ovsdb_idl_state new_state,
const char *where)
{
VLOG_DBG("%s: %s -> %s at %s",
jsonrpc_session_get_name(idl->session),
idl->session ? jsonrpc_session_get_name(idl->session) : "void",
ovsdb_idl_state_to_string(idl->state),
ovsdb_idl_state_to_string(new_state),
where);
Expand All @@ -615,7 +653,9 @@ ovsdb_idl_send_request(struct ovsdb_idl *idl, struct jsonrpc_msg *request)
{
json_destroy(idl->request_id);
idl->request_id = json_clone(request->id);
jsonrpc_session_send(idl->session, request);
if (idl->session) {
jsonrpc_session_send(idl->session, request);
}
}

static void
Expand Down Expand Up @@ -783,6 +823,11 @@ ovsdb_idl_process_msg(struct ovsdb_idl *idl, struct jsonrpc_msg *msg)
void
ovsdb_idl_run(struct ovsdb_idl *idl)
{
if (!idl->session) {
ovsdb_idl_txn_abort_all(idl);
return;
}

int i;

ovs_assert(!idl->data.txn);
Expand Down Expand Up @@ -822,6 +867,9 @@ ovsdb_idl_run(struct ovsdb_idl *idl)
void
ovsdb_idl_wait(struct ovsdb_idl *idl)
{
if (!idl->session) {
return;
}
jsonrpc_session_wait(idl->session);
jsonrpc_session_recv_wait(idl->session);
}
Expand Down Expand Up @@ -888,15 +936,19 @@ ovsdb_idl_has_ever_connected(const struct ovsdb_idl *idl)
void
ovsdb_idl_enable_reconnect(struct ovsdb_idl *idl)
{
jsonrpc_session_enable_reconnect(idl->session);
if (idl->session) {
jsonrpc_session_enable_reconnect(idl->session);
}
}

/* Forces 'idl' to drop its connection to the database and reconnect. In the
* meantime, the contents of 'idl' will not change. */
void
ovsdb_idl_force_reconnect(struct ovsdb_idl *idl)
{
jsonrpc_session_force_reconnect(idl->session);
if (idl->session) {
jsonrpc_session_force_reconnect(idl->session);
}
}

/* Some IDL users should only write to write-only columns. Furthermore,
Expand All @@ -914,7 +966,7 @@ ovsdb_idl_verify_write_only(struct ovsdb_idl *idl)
bool
ovsdb_idl_is_alive(const struct ovsdb_idl *idl)
{
return jsonrpc_session_is_alive(idl->session) &&
return idl->session && jsonrpc_session_is_alive(idl->session) &&
idl->state != IDL_S_ERROR;
}

Expand All @@ -932,10 +984,7 @@ ovsdb_idl_is_connected(const struct ovsdb_idl *idl)
int
ovsdb_idl_get_last_error(const struct ovsdb_idl *idl)
{
int err;

err = jsonrpc_session_get_last_error(idl->session);

int err = idl->session ? jsonrpc_session_get_last_error(idl->session) : 0;
if (err) {
return err;
} else if (idl->state == IDL_S_ERROR) {
Expand All @@ -951,7 +1000,9 @@ ovsdb_idl_get_last_error(const struct ovsdb_idl *idl)
void
ovsdb_idl_set_probe_interval(const struct ovsdb_idl *idl, int probe_interval)
{
jsonrpc_session_set_probe_interval(idl->session, probe_interval);
if (idl->session) {
jsonrpc_session_set_probe_interval(idl->session, probe_interval);
}
}

static size_t
Expand Down Expand Up @@ -4045,7 +4096,8 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn)
if (!any_updates) {
txn->status = TXN_UNCHANGED;
json_destroy(operations);
} else if (!jsonrpc_session_send(
} else if (txn->db->idl->session
&& !jsonrpc_session_send(
txn->db->idl->session,
jsonrpc_create_request(
"transact", operations, &txn->request_id))) {
Expand Down Expand Up @@ -4745,7 +4797,9 @@ ovsdb_idl_set_lock(struct ovsdb_idl *idl, const char *lock_name)
if (!msg) {
break;
}
jsonrpc_session_send(idl->session, msg);
if (idl->session) {
jsonrpc_session_send(idl->session, msg);
}
}
}

Expand Down
2 changes: 2 additions & 0 deletions lib/ovsdb-idl.h
View file
Expand Up @@ -60,6 +60,8 @@ struct ovsdb_idl *ovsdb_idl_create(const char *remote,
const struct ovsdb_idl_class *,
bool monitor_everything_by_default,
bool retry);
struct ovsdb_idl *ovsdb_idl_create_unconnected(
const struct ovsdb_idl_class *, bool monitor_everything_by_default);
void ovsdb_idl_set_remote(struct ovsdb_idl *, const char *, bool);
void ovsdb_idl_destroy(struct ovsdb_idl *);

Expand Down

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