[ovs-dev] [PATCH v4 1/2] ovsdb-idl : Add APIs to query if a table and a column is present or not.
Numan Siddique
numans at ovn.org
Wed Aug 25 23:44:44 UTC 2021
'
On Wed, Aug 25, 2021 at 6:06 PM Ilya Maximets <i.maximets at ovn.org> wrote:
>
> On 8/25/21 5:12 AM, numans at ovn.org wrote:
> > From: Numan Siddique <nusiddiq at redhat.com>
> >
> > This patch adds 2 new APIs in the ovsdb-idl client library
> > - ovsdb_idl_has_table() and ovsdb_idl_has_column_in_table() to
> > query if a table and a column is present in the IDL or not. This
> > is required for scenarios where the server schema is old and
> > missing a table or column and the client (built with a new schema
> > version) does a transaction with the missing table or column. This
> > results in a continuous loop of transaction failures.
> >
> > OVN would require the API - ovsdb_idl_has_table() to address this issue
> > when an old ovsdb-server is used (OVS 2.11) which has the 'datapath'
> > table missing. A recent commit in OVN creates a 'datapath' row
> > in the local ovsdb-server. ovsdb_idl_has_column_in_table() would be
> > useful to have.
> >
> > Related issue: https://bugzilla.redhat.com/show_bug.cgi?id=1992705
> > Signed-off-by: Numan Siddique <nusiddiq at redhat.com>
> > ---
> > lib/ovsdb-idl-provider.h | 4 +++
> > lib/ovsdb-idl.c | 36 ++++++++++++++++++++
> > lib/ovsdb-idl.h | 3 ++
> > tests/ovsdb-idl.at | 38 +++++++++++++++++++++
> > tests/test-ovsdb.c | 73 ++++++++++++++++++++++++++++++++++++++++
> > 5 files changed, 154 insertions(+)
> >
> > diff --git a/lib/ovsdb-idl-provider.h b/lib/ovsdb-idl-provider.h
> > index 0f38f9b34..0f122e23c 100644
> > --- a/lib/ovsdb-idl-provider.h
> > +++ b/lib/ovsdb-idl-provider.h
> > @@ -24,6 +24,7 @@
> > #include "ovsdb-set-op.h"
> > #include "ovsdb-types.h"
> > #include "openvswitch/shash.h"
> > +#include "sset.h"
> > #include "uuid.h"
> >
> > #ifdef __cplusplus
> > @@ -117,9 +118,12 @@ struct ovsdb_idl_table {
> > bool need_table; /* Monitor table even if no columns are selected
> > * for replication. */
> > struct shash columns; /* Contains "const struct ovsdb_idl_column *"s. */
> > + struct sset schema_columns; /* Column names from schema. */
>
> Why did you decide to go with sset instead of 'in_server_schema'
> boolean for the struct ovsdb_idl_column?
Two reasons:
1. The ovsdb_idl_column instances for each table columns are
generated automatically by ovsdb/ovsdb-idlc.in
2. 'struct ovsdb_idl_column *columns' is const in 'struct
ovsdb_idl_table_class'
https://github.com/openvswitch/ovs/blob/master/lib/ovsdb-idl.c#L722
>
> > struct hmap rows; /* Contains "struct ovsdb_idl_row"s. */
> > struct ovsdb_idl *idl; /* Containing IDL instance. */
> > unsigned int change_seqno[OVSDB_IDL_CHANGE_MAX];
> > + bool in_server_schema; /* Indicates if this table is in the server schema
> > + * or not. */
> > struct ovs_list indexes; /* Contains "struct ovsdb_idl_index"s */
> > struct ovs_list track_list; /* Tracked rows (ovsdb_idl_row.track_node). */
> > };
> > diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c
> > index 2198c69c6..b2dfff46c 100644
> > --- a/lib/ovsdb-idl.c
> > +++ b/lib/ovsdb-idl.c
> > @@ -287,6 +287,8 @@ ovsdb_idl_create_unconnected(const struct ovsdb_idl_class *class,
> > = table->change_seqno[OVSDB_IDL_CHANGE_MODIFY]
> > = table->change_seqno[OVSDB_IDL_CHANGE_DELETE] = 0;
> > table->idl = idl;
> > + table->in_server_schema = true; /* Assume it's in server schema. */
>
> Hmm. Why is that? We do not make assumptions about columns,
> we should, probably, not do that for tables too. What do
> you think?
I was thinking of the scenario where user calls ovsdb_has_table() at
the very beginning.
I'll remove it in v5.
>
> > + sset_init(&table->schema_columns);
> > }
> >
> > return idl;
> > @@ -337,6 +339,7 @@ ovsdb_idl_destroy(struct ovsdb_idl *idl)
> > struct ovsdb_idl_table *table = &idl->tables[i];
> > ovsdb_idl_destroy_indexes(table);
> > shash_destroy(&table->columns);
> > + sset_destroy(&table->schema_columns);
> > hmap_destroy(&table->rows);
> > free(table->modes);
> > }
> > @@ -718,6 +721,7 @@ ovsdb_idl_compose_monitor_request(const struct json *schema_json, void *idl_)
> >
> > struct json *columns
> > = table->need_table ? json_array_create_empty() : NULL;
> > + sset_clear(&table->schema_columns);
> > for (size_t j = 0; j < tc->n_columns; j++) {
> > const struct ovsdb_idl_column *column = &tc->columns[j];
> > bool idl_has_column = (table_schema &&
> > @@ -741,6 +745,7 @@ ovsdb_idl_compose_monitor_request(const struct json *schema_json, void *idl_)
> > }
> > json_array_add(columns, json_string_create(column->name));
> > }
> > + sset_add(&table->schema_columns, column->name);
> > }
> >
> > if (columns) {
> > @@ -749,7 +754,12 @@ ovsdb_idl_compose_monitor_request(const struct json *schema_json, void *idl_)
> > "(database needs upgrade?)",
> > idl->class_->database, table->class_->name);
> > json_destroy(columns);
> > + /* Set 'table->in_server_schema' to false so that this can be
> > + * excluded from transactions. */
>
> This comment seems redundant, since the functionality is in
> a different patch.
Ack.
>
> > + table->in_server_schema = false;
> > continue;
> > + } else if (schema && table_schema) {
> > + table->in_server_schema = true;
> > }
> >
> > monitor_request = json_object_create();
> > @@ -4256,3 +4266,29 @@ ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop *loop)
> >
> > return retval;
> > }
> > +
> > +static struct ovsdb_idl_table*
> > +ovsdb_idl_get_table(struct ovsdb_idl *idl, const char *table_name)
> > +{
> > + struct ovsdb_idl_table *table = shash_find_data(&idl->table_by_name,
> > + table_name);
> > + return table && table->in_server_schema ? table : NULL;
>
> It's better to parenthesize the condition, the priority of
> operations is not obvious.
Ack.
>
> > +}
> > +
> > +bool
> > +ovsdb_idl_has_table(struct ovsdb_idl *idl, const char *table_name)
> > +{
> > + return ovsdb_idl_get_table(idl, table_name) ? true: false;
>
> Missing space before the ':'.
Ack.
>
> > +}
> > +
> > +bool
> > +ovsdb_idl_has_column_in_table(struct ovsdb_idl *idl, const char *table_name,
> > + const char *column_name)
> > +{
> > + struct ovsdb_idl_table *table = ovsdb_idl_get_table(idl, table_name);
>
> Empty line here would be nice to have.
Ack.
>
> > + if (table && sset_find(&table->schema_columns, column_name)) {
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > diff --git a/lib/ovsdb-idl.h b/lib/ovsdb-idl.h
> > index d93483245..48425b39a 100644
> > --- a/lib/ovsdb-idl.h
> > +++ b/lib/ovsdb-idl.h
> > @@ -474,6 +474,9 @@ void ovsdb_idl_cursor_next_eq(struct ovsdb_idl_cursor *);
> >
> > struct ovsdb_idl_row *ovsdb_idl_cursor_data(struct ovsdb_idl_cursor *);
> >
> > +bool ovsdb_idl_has_table(struct ovsdb_idl *, const char *table_name);
> > +bool ovsdb_idl_has_column_in_table(struct ovsdb_idl *, const char *table_name,
> > + const char *column_name);
>
> This is a section of a header related to indexes and iteration.
> These functions should be defined somewhere close to
> ovsdb_idl_check_consistency() or ovsdb_idl_get_class().
Ack.
>
> > #ifdef __cplusplus
> > }
> > #endif
> > diff --git a/tests/ovsdb-idl.at b/tests/ovsdb-idl.at
> > index 1386f1377..b11fabe70 100644
> > --- a/tests/ovsdb-idl.at
> > +++ b/tests/ovsdb-idl.at
> > @@ -2372,3 +2372,41 @@ OVSDB_CHECK_CLUSTER_IDL([simple idl, initially empty, force reconnect],
> > [],
> > [],
> > reconnect.*waiting .* seconds before reconnect)
> > +
> > +AT_SETUP([idl table and column presence check])
> > +AT_KEYWORDS([ovsdb server idl table column check])
> > +AT_CHECK([ovsdb_start_idltest "" "$abs_srcdir/idltest2.ovsschema"])
> > +
> > +ovsdb-tool create db2 $abs_srcdir/idltest.ovsschema
> > +ovsdb-server -vconsole:warn --log-file=ovsdb-server2.log --detach --no-chdir --pidfile=ovsdb-server2.pid --remote=punix:socket2 db2
>
> Above two commands should be executed with AT_CHECK.
> It also would be nice to wrap the long line with 'dnl' inside AT_CHECK.
Ack.
>
> > +on_exit 'kill `cat ovsdb-server2.pid`'
> > +
> > +# In this test, test-ovsdb first connects to the server with schema
> > +# idltest2.ovsschema and outputs the presence of tables and columns.
> > +# And then it connectes to the server with the schema idltest.ovsschema
> > +# and does the same.
> > +AT_CHECK([test-ovsdb -vconsole:off -t10 idl-table-column-check unix:socket unix:socket2 \
>
> It's better to use 'dnl' for breaking lines, so it can be properly
> printed in the testsuite log.
Ack.
>
> > +simple link1 link2 simple5 foo simple5:irefmap simple5:foo link1:l2],
> > +[0], [dnl
> > +table simple is present
> > +table link1 is present
> > +table link2 is not present
> > +table simple5 is not present
> > +table foo is not present
> > +table simple5 is not present
> > +table simple5 is not present
> > +column l2 in table link1 is not present
> > +--- remote 1 done ---
> > +table simple is present
> > +table link1 is present
> > +table link2 is present
> > +table simple5 is present
> > +table foo is not present
> > +column irefmap in table simple5 is present
> > +column foo in table simple5 is not present
> > +column l2 in table link1 is present
> > +--- remote 2 done ---
> > +])
> > +
> > +OVSDB_SERVER_SHUTDOWN
> > +AT_CLEANUP
> > diff --git a/tests/test-ovsdb.c b/tests/test-ovsdb.c
> > index daa55dab7..462d2e57e 100644
> > --- a/tests/test-ovsdb.c
> > +++ b/tests/test-ovsdb.c
> > @@ -3268,6 +3268,77 @@ do_idl_compound_index(struct ovs_cmdl_context *ctx)
> > printf("%03d: done\n", step);
> > }
> >
> > +static void
> > +do_idl_table_column_check(struct ovs_cmdl_context *ctx)
> > +{
> > + struct jsonrpc *rpc;
> > + struct ovsdb_idl *idl;
> > + unsigned int seqno = 0;
> > + int error;
> > + int i;
> > +
> > + if (ctx->argc < 3) {
> > + exit(1);
> > + }
> > +
> > + idl = ovsdb_idl_create(ctx->argv[1], &idltest_idl_class, true, true);
> > + ovsdb_idl_set_leader_only(idl, false);
> > + struct stream *stream;
> > +
> > + error = stream_open_block(jsonrpc_stream_open(ctx->argv[1], &stream,
> > + DSCP_DEFAULT), -1, &stream);
> > + if (error) {
> > + ovs_fatal(error, "failed to connect to \"%s\"", ctx->argv[1]);
> > + }
> > + rpc = jsonrpc_open(stream);
> > +
> > + for (int r = 1; r <= 2; r++) {
> > + ovsdb_idl_set_remote(idl, ctx->argv[r], true);
> > + ovsdb_idl_force_reconnect(idl);
> > +
> > + /* Wait for update. */
> > + for (;;) {
> > + ovsdb_idl_run(idl);
> > + ovsdb_idl_check_consistency(idl);
> > + if (ovsdb_idl_get_seqno(idl) != seqno) {
> > + break;
> > + }
> > + jsonrpc_run(rpc);
> > +
> > + ovsdb_idl_wait(idl);
> > + jsonrpc_wait(rpc);
> > + poll_block();
> > + }
> > +
> > + seqno = ovsdb_idl_get_seqno(idl);
> > +
> > + for (i = 3; i < ctx->argc; i++) {
> > + char *save_ptr2 = NULL;
> > + char *arg = xstrdup(ctx->argv[i]);
> > + char *table_name = strtok_r(arg, ":", &save_ptr2);
> > + char *column_name = strtok_r(NULL, ":", &save_ptr2);
> > +
> > + bool table_present = ovsdb_idl_has_table(idl, table_name);
> > + if (!table_present || !column_name) {
> > + printf("table %s %s present\n", table_name,
> > + table_present ? "is" : "is not");
>
> Please shif this line to be on the same level with the text inside
> the '()' above.
Ack.
>
> > + }
> > + if (table_present && column_name) {
> > + printf("column %s in table %s %s present\n", column_name,
> > + table_name,
> > + ovsdb_idl_has_column_in_table(idl, table_name,
> > + column_name) ?
> > + "is" : "is not");
>
> Maybe:
>
> bool in = ovsdb_idl_has_column_in_table(idl, table_name,
> column_name);
> printf("column %s in table %s %s present\n",
> column_name, table_name, in ? "is" : "is not");
> ?
>
Ack.
> > + }
> > + free(arg);
> > + }
> > + printf("--- remote %d done ---\n", r);
> > + }
> > +
> > + jsonrpc_close(rpc);
> > + ovsdb_idl_destroy(idl);
> > +}
> > +
> > static struct ovs_cmdl_command all_commands[] = {
> > { "log-io", NULL, 2, INT_MAX, do_log_io, OVS_RO },
> > { "default-atoms", NULL, 0, 0, do_default_atoms, OVS_RO },
> > @@ -3306,6 +3377,8 @@ static struct ovs_cmdl_command all_commands[] = {
> > do_idl_partial_update_map_column, OVS_RO },
> > { "idl-partial-update-set-column", NULL, 1, INT_MAX,
> > do_idl_partial_update_set_column, OVS_RO },
> > + { "idl-table-column-check", NULL, 1, INT_MAX,
>
> It should be 2, I think, instead of 1, right? And you may remove
> the check for number of arguments from the function.
Correct. I'll fix in v5.
Thanks for the review.
Numan
>
> > + do_idl_table_column_check, OVS_RO },
> > { "help", NULL, 0, INT_MAX, do_help, OVS_RO },
> > { NULL, NULL, 0, 0, NULL, OVS_RO },
> > };
> >
>
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