diff --git a/doc/src/sgml/event-trigger.sgml b/doc/src/sgml/event-trigger.sgml
index 60366a9..f7c3c14 100644
--- a/doc/src/sgml/event-trigger.sgml
+++ b/doc/src/sgml/event-trigger.sgml
@@ -28,12 +28,31 @@
An event trigger fires whenever the event with which it is associated
occurs in the database in which it is defined. Currently, the only
supported events are
+ session_start,
ddl_command_start,
ddl_command_end,
table_rewrite
and sql_drop.
Support for additional events may be added in future releases.
+table_rewrite
+
+ The session_start event occurs on backend start when connection with user was established.
+ As far as bug in trigger procedure can prevent normal login to the system, there are two mechanisms
+ for preventing it:
+
+
+
+ GUC disable_session_start_trigger which makes it possible to disable firing triggers on session startup.
+
+
+
+ Ignoring errors in trigger procedure for superuser. Error message is delivered to client as NOTICE
+ in this case
+
+
+
+
The ddl_command_start event occurs just before the
diff --git a/src/backend/commands/event_trigger.c b/src/backend/commands/event_trigger.c
index 7844880..a341fee 100644
--- a/src/backend/commands/event_trigger.c
+++ b/src/backend/commands/event_trigger.c
@@ -48,6 +48,8 @@
#include "utils/rel.h"
#include "utils/syscache.h"
+bool disable_session_start_trigger;
+
typedef struct EventTriggerQueryState
{
/* memory context for this state's objects */
@@ -130,6 +132,7 @@ CreateEventTrigger(CreateEventTrigStmt *stmt)
if (strcmp(stmt->eventname, "ddl_command_start") != 0 &&
strcmp(stmt->eventname, "ddl_command_end") != 0 &&
strcmp(stmt->eventname, "sql_drop") != 0 &&
+ strcmp(stmt->eventname, "session_start") != 0 &&
strcmp(stmt->eventname, "table_rewrite") != 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
@@ -562,6 +565,9 @@ EventTriggerCommonSetup(Node *parsetree,
ListCell *lc;
List *runlist = NIL;
+ /* Get the command tag. */
+ tag = parsetree ? CreateCommandTag(parsetree) : CMDTAG_CONNECT;
+
/*
* We want the list of command tags for which this procedure is actually
* invoked to match up exactly with the list that CREATE EVENT TRIGGER
@@ -577,22 +583,18 @@ EventTriggerCommonSetup(Node *parsetree,
* relevant command tag.
*/
#ifdef USE_ASSERT_CHECKING
+ if (event == EVT_DDLCommandStart ||
+ event == EVT_DDLCommandEnd ||
+ event == EVT_SQLDrop ||
+ event == EVT_Connect)
{
- CommandTag dbgtag;
-
- dbgtag = CreateCommandTag(parsetree);
- if (event == EVT_DDLCommandStart ||
- event == EVT_DDLCommandEnd ||
- event == EVT_SQLDrop)
- {
- if (!command_tag_event_trigger_ok(dbgtag))
- elog(ERROR, "unexpected command tag \"%s\"", GetCommandTagName(dbgtag));
- }
- else if (event == EVT_TableRewrite)
- {
- if (!command_tag_table_rewrite_ok(dbgtag))
- elog(ERROR, "unexpected command tag \"%s\"", GetCommandTagName(dbgtag));
- }
+ if (!command_tag_event_trigger_ok(tag))
+ elog(ERROR, "unexpected command tag \"%s\"", GetCommandTagName(tag));
+ }
+ else if (event == EVT_TableRewrite)
+ {
+ if (!command_tag_table_rewrite_ok(tag))
+ elog(ERROR, "unexpected command tag \"%s\"", GetCommandTagName(tag));
}
#endif
@@ -601,9 +603,6 @@ EventTriggerCommonSetup(Node *parsetree,
if (cachelist == NIL)
return NIL;
- /* Get the command tag. */
- tag = CreateCommandTag(parsetree);
-
/*
* Filter list of event triggers by command tag, and copy them into our
* memory context. Once we start running the command triggers, or indeed
@@ -800,6 +799,66 @@ EventTriggerSQLDrop(Node *parsetree)
list_free(runlist);
}
+/*
+ * Fire connect triggers.
+ */
+void
+EventTriggerOnConnect(void)
+{
+ List *runlist;
+ EventTriggerData trigdata;
+
+ /*
+ * See EventTriggerDDLCommandStart for a discussion about why event
+ * triggers are disabled in single user mode.
+ */
+ if (!IsUnderPostmaster || !OidIsValid(MyDatabaseId) || disable_session_start_trigger)
+ return;
+
+ StartTransactionCommand();
+
+ runlist = EventTriggerCommonSetup(NULL,
+ EVT_Connect, "connect",
+ &trigdata);
+
+ if (runlist != NIL)
+ {
+ MemoryContext old_context = CurrentMemoryContext;
+ bool is_superuser = superuser();
+ /*
+ * Make sure anything the main command did will be visible to the event
+ * triggers.
+ */
+ CommandCounterIncrement();
+
+ /* Run the triggers. */
+ PG_TRY();
+ {
+ EventTriggerInvoke(runlist, &trigdata);
+ list_free(runlist);
+ }
+ PG_CATCH();
+ {
+ ErrorData* error;
+ /*
+ * Try to ignore error for superuser to make it possible to login even in case of errors
+ * during trigger execution
+ */
+ if (!is_superuser)
+ PG_RE_THROW();
+
+ MemoryContextSwitchTo(old_context);
+ error = CopyErrorData();
+ FlushErrorState();
+ elog(NOTICE, "start_session trigger failed with message %s", error->message);
+ AbortCurrentTransaction();
+ return;
+ }
+ PG_END_TRY();
+ }
+ CommitTransactionCommand();
+}
+
/*
* Fire table_rewrite triggers.
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index c9424f1..008e574 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -42,6 +42,7 @@
#include "catalog/pg_type.h"
#include "commands/async.h"
#include "commands/prepare.h"
+#include "commands/event_trigger.h"
#include "executor/spi.h"
#include "jit/jit.h"
#include "libpq/libpq.h"
@@ -167,6 +168,9 @@ static ProcSignalReason RecoveryConflictReason;
static MemoryContext row_description_context = NULL;
static StringInfoData row_description_buf;
+/* Hook for plugins to get control at start of session */
+session_start_hook_type session_start_hook = EventTriggerOnConnect;
+
/* ----------------------------------------------------------------
* decls for routines only used in this file
* ----------------------------------------------------------------
@@ -4017,6 +4021,11 @@ PostgresMain(int argc, char *argv[],
if (!IsUnderPostmaster)
PgStartTime = GetCurrentTimestamp();
+ if (session_start_hook)
+ {
+ (*session_start_hook) ();
+ }
+
/*
* POSTGRES main processing loop begins here
*
diff --git a/src/backend/utils/cache/evtcache.c b/src/backend/utils/cache/evtcache.c
index 73d091d..6eaac13 100644
--- a/src/backend/utils/cache/evtcache.c
+++ b/src/backend/utils/cache/evtcache.c
@@ -169,6 +169,8 @@ BuildEventTriggerCache(void)
event = EVT_SQLDrop;
else if (strcmp(evtevent, "table_rewrite") == 0)
event = EVT_TableRewrite;
+ else if (strcmp(evtevent, "session_start") == 0)
+ event = EVT_Connect;
else
continue;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 73518d9..5ced24f 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -43,6 +43,7 @@
#include "commands/async.h"
#include "commands/prepare.h"
#include "commands/trigger.h"
+#include "commands/event_trigger.h"
#include "commands/user.h"
#include "commands/vacuum.h"
#include "commands/variable.h"
@@ -928,6 +929,16 @@ static const unit_conversion time_unit_conversion_table[] =
static struct config_bool ConfigureNamesBool[] =
{
{
+ {"disable_session_start_trigger", PGC_SU_BACKEND, DEVELOPER_OPTIONS,
+ gettext_noop("Disable on session_start event trigger."),
+ gettext_noop("In case of errors in ON session_start EVENT TRIGGER procedure this GUC can be used to disable trigger activation and provide access to the database."),
+ GUC_EXPLAIN
+ },
+ &disable_session_start_trigger,
+ false,
+ NULL, NULL, NULL
+ },
+ {
{"enable_seqscan", PGC_USERSET, QUERY_TUNING_METHOD,
gettext_noop("Enables the planner's use of sequential-scan plans."),
NULL,
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index 407fd6a..61c096d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -21,6 +21,8 @@
#include "tcop/deparse_utility.h"
#include "utils/aclchk_internal.h"
+extern bool disable_session_start_trigger; /* GUC */
+
typedef struct EventTriggerData
{
NodeTag type;
@@ -53,6 +55,7 @@ extern void EventTriggerDDLCommandStart(Node *parsetree);
extern void EventTriggerDDLCommandEnd(Node *parsetree);
extern void EventTriggerSQLDrop(Node *parsetree);
extern void EventTriggerTableRewrite(Node *parsetree, Oid tableOid, int reason);
+extern void EventTriggerOnConnect(void);
extern bool EventTriggerBeginCompleteQuery(void);
extern void EventTriggerEndCompleteQuery(void);
diff --git a/src/include/tcop/cmdtaglist.h b/src/include/tcop/cmdtaglist.h
index 8ef0f55..cba70b3 100644
--- a/src/include/tcop/cmdtaglist.h
+++ b/src/include/tcop/cmdtaglist.h
@@ -80,6 +80,7 @@ PG_CMDTAG(CMDTAG_CLUSTER, "CLUSTER", false, false, false)
PG_CMDTAG(CMDTAG_COMMENT, "COMMENT", true, false, false)
PG_CMDTAG(CMDTAG_COMMIT, "COMMIT", false, false, false)
PG_CMDTAG(CMDTAG_COMMIT_PREPARED, "COMMIT PREPARED", false, false, false)
+PG_CMDTAG(CMDTAG_CONNECT, "CONNECT", true, false, false)
PG_CMDTAG(CMDTAG_COPY, "COPY", false, false, true)
PG_CMDTAG(CMDTAG_COPY_FROM, "COPY FROM", false, false, false)
PG_CMDTAG(CMDTAG_CREATE_ACCESS_METHOD, "CREATE ACCESS METHOD", true, false, false)
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index bd30607..be71020 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -30,6 +30,11 @@ extern PGDLLIMPORT const char *debug_query_string;
extern int max_stack_depth;
extern int PostAuthDelay;
+/* Hook for plugins to get control at start and end of session */
+typedef void (*session_start_hook_type) (void);
+
+extern PGDLLIMPORT session_start_hook_type session_start_hook;
+
/* GUC-configurable parameters */
typedef enum
diff --git a/src/include/utils/evtcache.h b/src/include/utils/evtcache.h
index bb1e39e..ab7e8c3 100644
--- a/src/include/utils/evtcache.h
+++ b/src/include/utils/evtcache.h
@@ -22,7 +22,8 @@ typedef enum
EVT_DDLCommandStart,
EVT_DDLCommandEnd,
EVT_SQLDrop,
- EVT_TableRewrite
+ EVT_TableRewrite,
+ EVT_Connect,
} EventTriggerEvent;
typedef struct
diff --git a/src/test/recovery/t/000_session_start_trigger.pl b/src/test/recovery/t/000_session_start_trigger.pl
new file mode 100644
index 0000000..fa82e0a
--- /dev/null
+++ b/src/test/recovery/t/000_session_start_trigger.pl
@@ -0,0 +1,69 @@
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More;
+if (!$use_unix_sockets)
+{
+ plan skip_all =>
+ "authentication tests cannot run without Unix-domain sockets";
+}
+else
+{
+ plan tests => 5;
+}
+
+# Initialize master node
+my $node = get_new_node('master');
+$node->init;
+$node->start;
+$node->safe_psql('postgres', q{
+CREATE ROLE regress_user LOGIN PASSWORD 'pass';
+CREATE ROLE regress_hacker LOGIN PASSWORD 'pass';
+
+CREATE TABLE connects(id serial, who text);
+
+CREATE FUNCTION on_login_proc() RETURNS EVENT_TRIGGER AS $$
+BEGIN
+ IF NOT pg_is_in_recovery() THEN
+ INSERT INTO connects (who) VALUES (session_user);
+ END IF;
+ IF session_user = 'regress_hacker' THEN
+ RAISE EXCEPTION 'You are not welcome!';
+ END IF;
+ RAISE NOTICE 'You are welcome!';
+END;
+$$ LANGUAGE plpgsql SECURITY DEFINER;
+
+CREATE EVENT TRIGGER on_login_trigger ON session_start EXECUTE FUNCTION on_login_proc();
+ALTER EVENT TRIGGER on_login_trigger ENABLE ALWAYS;
+}
+);
+my $res;
+
+$res = $node->safe_psql('postgres', "SELECT 1");
+
+$res = $node->safe_psql('postgres', "SELECT 1",
+ extra_params => [ '-U', 'regress_user', '-w' ]);
+
+my ($ret, $stdout, $stderr) = $node->psql('postgres', "SELECT 1",
+ extra_params => [ '-U', 'regress_hacker', '-w' ]);
+ok( $ret != 0 && $stderr =~ /You are not welcome!/ );
+
+$res = $node->safe_psql('postgres', "SELECT COUNT(1) FROM connects WHERE who = 'regress_user'");
+ok($res == 1);
+
+my $tempdir = TestLib::tempdir;
+command_ok(
+ [ "pg_dumpall", '-p', $node->port, '-c', "--file=$tempdir/regression_dump.sql", ],
+ "dumpall");
+# my $dump_contents = slurp_file("$tempdir/regression_dump.sql");
+# print($dump_contents);
+
+my $node1 = get_new_node('secondary');
+$node1->init;
+$node1->start;
+command_ok(["psql", '-p', $node1->port, '-b', '-f', "$tempdir/regression_dump.sql" ] );
+$res = $node1->safe_psql('postgres', "SELECT 1", extra_params => [ '-U', 'regress_user', '-w' ]);
+$res = $node1->safe_psql('postgres', "SELECT COUNT(1) FROM connects WHERE who = 'regress_user'");
+ok($res == 2);
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 9e31a53..5e9dc5f 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -43,6 +43,27 @@ $node_standby_2->start;
$node_primary->safe_psql('postgres',
"CREATE TABLE tab_int AS SELECT generate_series(1,1002) AS a");
+$node_primary->safe_psql('postgres', q{
+CREATE ROLE regress_user LOGIN PASSWORD 'pass';
+
+CREATE TABLE connects(id serial, who text);
+
+CREATE FUNCTION on_login_proc() RETURNS EVENT_TRIGGER AS $$
+BEGIN
+ IF NOT pg_is_in_recovery() THEN
+ INSERT INTO connects (who) VALUES (session_user);
+ END IF;
+ IF session_user = 'regress_hacker' THEN
+ RAISE EXCEPTION 'You are not welcome!';
+ END IF;
+ RAISE NOTICE 'You are welcome!';
+END;
+$$ LANGUAGE plpgsql SECURITY DEFINER;
+
+CREATE EVENT TRIGGER on_login_trigger ON session_start EXECUTE FUNCTION on_login_proc();
+ALTER EVENT TRIGGER on_login_trigger ENABLE ALWAYS;
+});
+
# Wait for standbys to catch up
$node_primary->wait_for_catchup($node_standby_1, 'replay',
$node_primary->lsn('insert'));
@@ -266,6 +287,9 @@ sub replay_check
replay_check();
+$node_standby_1->safe_psql('postgres', "SELECT 1", extra_params => [ '-U', 'regress_user', '-w' ]);
+$node_standby_2->safe_psql('postgres', "SELECT 2", extra_params => [ '-U', 'regress_user', '-w' ]);
+
note "enabling hot_standby_feedback";
# Enable hs_feedback. The slot should gain an xmin. We set the status interval
diff --git a/src/test/regress/expected/event_trigger.out b/src/test/regress/expected/event_trigger.out
index bdd0ffc..e0b5196 100644
--- a/src/test/regress/expected/event_trigger.out
+++ b/src/test/regress/expected/event_trigger.out
@@ -536,3 +536,40 @@ NOTICE: DROP POLICY - ddl_command_end
DROP EVENT TRIGGER start_rls_command;
DROP EVENT TRIGGER end_rls_command;
DROP EVENT TRIGGER sql_drop_command;
+-- On session start triggers
+create table connects(id serial, who text);
+create function on_login_proc() returns event_trigger as $$
+begin
+ insert into connects (who) values ('I am');
+ raise notice 'You are welcome!';
+end;
+$$ language plpgsql;
+create event trigger on_login_trigger on session_start execute procedure on_login_proc();
+alter event trigger on_login_trigger enable always;
+\c
+NOTICE: You are welcome!
+select * from connects;
+ id | who
+----+------
+ 1 | I am
+(1 row)
+
+\c
+NOTICE: You are welcome!
+select * from connects;
+ id | who
+----+------
+ 1 | I am
+ 2 | I am
+(2 rows)
+
+-- Test handing exeptions in session_start trigger
+drop table connects;
+-- superuser should ignore error
+\c
+NOTICE: start_session trigger failed with message relation "connects" does not exist
+-- suppress troigger firing
+\c "dbname=regression options='-c disable_session_start_trigger=true'"
+-- Cleanup
+drop event trigger on_login_trigger;
+drop function on_login_proc();
diff --git a/src/test/regress/sql/event_trigger.sql b/src/test/regress/sql/event_trigger.sql
index 18b2a26..82dacdd 100644
--- a/src/test/regress/sql/event_trigger.sql
+++ b/src/test/regress/sql/event_trigger.sql
@@ -429,3 +429,31 @@ DROP POLICY p2 ON event_trigger_test;
DROP EVENT TRIGGER start_rls_command;
DROP EVENT TRIGGER end_rls_command;
DROP EVENT TRIGGER sql_drop_command;
+
+-- On session start triggers
+create table connects(id serial, who text);
+create function on_login_proc() returns event_trigger as $$
+begin
+ insert into connects (who) values ('I am');
+ raise notice 'You are welcome!';
+end;
+$$ language plpgsql;
+create event trigger on_login_trigger on session_start execute procedure on_login_proc();
+alter event trigger on_login_trigger enable always;
+\c
+select * from connects;
+\c
+select * from connects;
+
+-- Test handing exeptions in session_start trigger
+
+drop table connects;
+-- superuser should ignore error
+\c
+-- suppress troigger firing
+\c "dbname=regression options='-c disable_session_start_trigger=true'"
+
+
+-- Cleanup
+drop event trigger on_login_trigger;
+drop function on_login_proc();