[ovs-dev] [PATCH RFC] ovsdb-server: Preserve remotes across crash and restart.
Ben Pfaff
blp at nicira.com
Thu Jun 13 00:10:09 UTC 2013
---
This is unpolished but it shows the approach I have in mind.
Sending out for comments on the approach.
diff --git a/ovsdb/ovsdb-server.c b/ovsdb/ovsdb-server.c
index 20e1964..d87360a 100644
--- a/ovsdb/ovsdb-server.c
+++ b/ovsdb/ovsdb-server.c
@@ -81,8 +81,14 @@ struct add_remote_aux {
struct sset *remotes;
struct db *dbs;
size_t n_dbs;
+ FILE *config_tmpfile;
};
static unixctl_cb_func ovsdb_server_add_remote;
+
+struct remove_remote_aux {
+ struct sset *remotes;
+ FILE *config_tmpfile;
+};
static unixctl_cb_func ovsdb_server_remove_remote;
static unixctl_cb_func ovsdb_server_list_remotes;
@@ -99,6 +105,9 @@ static void update_remote_status(const struct ovsdb_jsonrpc_server *jsonrpc,
const struct sset *remotes,
struct db dbs[], size_t n_dbs);
+static void save_config(FILE *config_file, const struct sset *);
+static void load_config(FILE *config_file, struct sset *);
+
int
main(int argc, char *argv[])
{
@@ -112,6 +121,8 @@ main(int argc, char *argv[])
int retval;
long long int status_timer = LLONG_MIN;
struct add_remote_aux add_remote_aux;
+ struct remove_remote_aux remove_remote_aux;
+ FILE *config_tmpfile;
struct db *dbs;
int n_dbs;
@@ -125,7 +136,14 @@ main(int argc, char *argv[])
parse_options(&argc, &argv, &remotes, &unixctl_path, &run_command);
+ config_tmpfile = tmpfile();
+ if (!config_tmpfile) {
+ ovs_fatal(errno, "failed to create temporary file");
+ }
+
+ save_config(config_tmpfile, &remotes);
daemonize_start();
+ load_config(config_tmpfile, &remotes);
n_dbs = MAX(1, argc);
dbs = xcalloc(n_dbs + 1, sizeof *dbs);
@@ -195,10 +213,13 @@ main(int argc, char *argv[])
add_remote_aux.remotes = &remotes;
add_remote_aux.dbs = dbs;
add_remote_aux.n_dbs = n_dbs;
+ add_remote_aux.config_tmpfile = config_tmpfile;
unixctl_command_register("ovsdb-server/add-remote", "REMOTE", 1, 1,
ovsdb_server_add_remote, &add_remote_aux);
+ remove_remote_aux.remotes = &remotes;
+ remove_remote_aux.config_tmpfile = config_tmpfile;
unixctl_command_register("ovsdb-server/remove-remote", "REMOTE", 1, 1,
- ovsdb_server_remove_remote, &remotes);
+ ovsdb_server_remove_remote, &remove_remote_aux);
unixctl_command_register("ovsdb-server/list-remotes", "", 0, 0,
ovsdb_server_list_remotes, &remotes);
@@ -922,7 +943,9 @@ ovsdb_server_add_remote(struct unixctl_conn *conn, int argc OVS_UNUSED,
: parse_db_column(aux->dbs, aux->n_dbs, remote,
&db, &table, &column));
if (!retval) {
- sset_add(aux->remotes, remote);
+ if (sset_add(aux->remotes, remote)) {
+ save_config(aux->config_tmpfile, aux->remotes);
+ }
unixctl_command_reply(conn, NULL);
} else {
unixctl_command_reply_error(conn, retval);
@@ -934,14 +957,15 @@ ovsdb_server_add_remote(struct unixctl_conn *conn, int argc OVS_UNUSED,
* that ovsdb-server services. */
static void
ovsdb_server_remove_remote(struct unixctl_conn *conn, int argc OVS_UNUSED,
- const char *argv[], void *remotes_)
+ const char *argv[], void *aux_)
{
- struct sset *remotes = remotes_;
+ struct remove_remote_aux *aux = aux_;
struct sset_node *node;
- node = sset_find(remotes, argv[1]);
+ node = sset_find(aux->remotes, argv[1]);
if (node) {
- sset_delete(remotes, node);
+ sset_delete(aux->remotes, node);
+ save_config(aux->config_tmpfile, aux->remotes);
unixctl_command_reply(conn, NULL);
} else {
unixctl_command_reply_error(conn, "no such remote");
@@ -1092,3 +1116,48 @@ usage(void)
leak_checker_usage();
exit(EXIT_SUCCESS);
}
+
+static void
+save_config(FILE *config_file, const struct sset *remotes)
+{
+ const char *remote;
+ struct json *json;
+ char *s;
+
+ if (ftruncate(fileno(config_file), 0) == -1) {
+ ovs_fatal(errno, "truncate failed");
+ }
+
+ json = json_array_create_empty();
+ SSET_FOR_EACH (remote, remotes) {
+ json_array_add(json, json_string_create(remote));
+ }
+ s = json_to_string(json, 0);
+ json_destroy(json);
+
+ if (fputs(s, config_file) == EOF || fflush(config_file) == EOF) {
+ ovs_fatal(errno, "write failed");
+ }
+ free(s);
+}
+
+static void
+load_config(FILE *config_file, struct sset *remotes)
+{
+ struct json *json;
+ size_t i;
+
+ sset_clear(remotes);
+
+ rewind(config_file);
+ json = json_from_stream(config_file);
+ if (json->type == JSON_STRING) {
+ ovs_fatal(0, "reading json failed (%s)", json_string(json));
+ }
+ ovs_assert(json->type == JSON_ARRAY);
+ for (i = 0; i < json->u.array.n; i++) {
+ const struct json *remote = json->u.array.elems[i];
+ sset_add(remotes, json_string(remote));
+ }
+ json_destroy(json);
+}
--
1.7.2.5
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