Message-ID: <6760a25e.a70a0220.2e9d8f.d542@mx.google.com>
Sender: Michael Banck <mbanck@gmail.com>
Date: Mon, 16 Dec 2024 22:57:49 +0100
From: Michael Banck <mbanck@gmx.net>
To: Michael Paquier <michael@paquier.xyz>
Cc: Greg Sabino Mullane <htamfids@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: [PATCH] Add support for displaying database service in psql
 prompt
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Hi Michael,

On Tue, Dec 10, 2024 at 04:38:24PM +0900, Michael Paquier wrote:
> On Thu, Nov 28, 2024 at 09:17:23PM +0100, Michael Banck wrote:
> > On Tue, Nov 19, 2024 at 07:47:58PM -0500, Greg Sabino Mullane wrote:
> > > Compiled and tested: works fine, so +1 from me. Honestly, I was surprised
> > > %s was still available. :)
> > 
> > Thanks. Was that full review? You kept the commitfest item in "Needs
> > Review" state.
> 
> No objections to this proposal, that can be useful.  No objections
> with the use of 's' for the shortcut in the psql prompt.

Cool.
 
> Back to your patch, you are missing two things at quick glance:
> - Documentation for the new libpq API in 0001.
> - Documentation for the new SERVICE and its new %s (see section called
> "Prompting" on the psql page.
> 
> So please make sure to provide these with the next version of the
> patch.

Thanks, I have added the documentation now in v2.


Michael

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Content-Disposition: attachment; filename="v2-0001-Add-PQservice-to-PGConn.patch"

From 666b80297f1cb918230b5104e2e8dce08b711394 Mon Sep 17 00:00:00 2001
From: Michael Banck <michael.banck@credativ.de>
Date: Thu, 31 Oct 2024 18:27:52 +0100
Subject: [PATCH v2 1/2] Add PQservice to PGConn.

This adds the content of the database service (if any) to PGConn. One
use for this would be for psql to display the service as part of the
prompt. It also adds PGservice() as a new connection status unction.
---
 doc/src/sgml/libpq.sgml           | 20 ++++++++++++++++++++
 src/interfaces/libpq/exports.txt  |  1 +
 src/interfaces/libpq/fe-connect.c | 11 ++++++++++-
 src/interfaces/libpq/libpq-fe.h   |  1 +
 src/interfaces/libpq/libpq-int.h  |  1 +
 5 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 01f259fd0d..105b22b317 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -2530,6 +2530,26 @@ char *PQport(const PGconn *conn);
      </listitem>
     </varlistentry>
 
+    <varlistentry id="libpq-PQservice">
+     <term><function>PQservice</function><indexterm><primary>PQservice</primary></indexterm></term>
+
+     <listitem>
+      <para>
+       Returns the service of the active connection.
+
+<synopsis>
+char *PQservice(const PGconn *conn);
+</synopsis>
+      </para>
+
+      <para>
+       <xref linkend="libpq-PQservice"/> returns <symbol>NULL</symbol> if the
+       <parameter>conn</parameter> argument is <symbol>NULL</symbol>.
+       Otherwise, if there was no service provided, it returns an empty string.
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry id="libpq-PQtty">
      <term><function>PQtty</function><indexterm><primary>PQtty</primary></indexterm></term>
 
diff --git a/src/interfaces/libpq/exports.txt b/src/interfaces/libpq/exports.txt
index 5d8213e0b5..2ad2cbf5ca 100644
--- a/src/interfaces/libpq/exports.txt
+++ b/src/interfaces/libpq/exports.txt
@@ -205,3 +205,4 @@ PQcancelFinish            202
 PQsocketPoll              203
 PQsetChunkedRowsMode      204
 PQgetCurrentTimeUSec      205
+PQservice                 206
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index aaf87e8e88..ddcc7b60ab 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -190,7 +190,8 @@ typedef struct _internalPQconninfoOption
 
 static const internalPQconninfoOption PQconninfoOptions[] = {
 	{"service", "PGSERVICE", NULL, NULL,
-	"Database-Service", "", 20, -1},
+		"Database-Service", "", 20,
+	offsetof(struct pg_conn, pgservice)},
 
 	{"user", "PGUSER", NULL, NULL,
 		"Database-User", "", 20,
@@ -7040,6 +7041,14 @@ PQdb(const PGconn *conn)
 	return conn->dbName;
 }
 
+char *
+PQservice(const PGconn *conn)
+{
+	if (!conn)
+		return NULL;
+	return conn->pgservice;
+}
+
 char *
 PQuser(const PGconn *conn)
 {
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index 15012c770c..5947e7c766 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -385,6 +385,7 @@ extern int	PQrequestCancel(PGconn *conn);
 
 /* Accessor functions for PGconn objects */
 extern char *PQdb(const PGconn *conn);
+extern char *PQservice(const PGconn *conn);
 extern char *PQuser(const PGconn *conn);
 extern char *PQpass(const PGconn *conn);
 extern char *PQhost(const PGconn *conn);
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 08cc391cbd..dcebca9898 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -394,6 +394,7 @@ struct pg_conn
 	char	   *fbappname;		/* fallback application name */
 	char	   *dbName;			/* database name */
 	char	   *replication;	/* connect as the replication standby? */
+	char	   *pgservice;		/* Postgres service, if any */
 	char	   *pguser;			/* Postgres username and password, if any */
 	char	   *pgpass;
 	char	   *pgpassfile;		/* path to a file containing password(s) */
-- 
2.39.5


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Content-Disposition: attachment; filename="v2-0002-Add-support-for-database-service-to-psql-prompt.patch"

From 5faa624871e3267a780d794e9ad2e9f42fd42311 Mon Sep 17 00:00:00 2001
From: Michael Banck <michael.banck@credativ.de>
Date: Thu, 31 Oct 2024 18:49:14 +0100
Subject: [PATCH v2 2/2] Add support for database service to psql prompt.

This adds a new psql variable SERVICE as well as the string '%s' for the
psql PROMPT, displaying the service (from PGSERVICEFILE) if so desired.
---
 doc/src/sgml/ref/psql-ref.sgml | 14 ++++++++++++++
 src/bin/psql/command.c         |  2 ++
 src/bin/psql/prompt.c          |  6 ++++++
 3 files changed, 22 insertions(+)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index e42073ed74..af78e0e87b 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -4380,6 +4380,15 @@ bar
         </listitem>
       </varlistentry>
 
+      <varlistentry id="app-psql-variables-service">
+        <term><varname>SERVICE</varname></term>
+        <listitem>
+        <para>
+        The service from <filename>pg_service.conf</filename>, if applicable.
+        </para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry id="app-psql-variables-shell-error">
        <term><varname>SHELL_ERROR</varname></term>
        <listitem>
@@ -4685,6 +4694,11 @@ testdb=&gt; <userinput>INSERT INTO my_table VALUES (:'content');</userinput>
          (tilde) if the database is your default database.</para></listitem>
       </varlistentry>
 
+      <varlistentry id="app-psql-prompting-s">
+        <term><literal>%s</literal></term>
+        <listitem><para>The name of the service entry, if any.</para></listitem>
+      </varlistentry>
+
       <varlistentry id="app-psql-prompting-numbersign">
         <term><literal>%#</literal></term>
         <listitem>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 1f3cbb11f7..cd16f27947 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -4082,6 +4082,7 @@ SyncVariables(void)
 	pset.sversion = PQserverVersion(pset.db);
 
 	SetVariable(pset.vars, "DBNAME", PQdb(pset.db));
+	SetVariable(pset.vars, "SERVICE", PQservice(pset.db));
 	SetVariable(pset.vars, "USER", PQuser(pset.db));
 	SetVariable(pset.vars, "HOST", PQhost(pset.db));
 	SetVariable(pset.vars, "PORT", PQport(pset.db));
@@ -4115,6 +4116,7 @@ void
 UnsyncVariables(void)
 {
 	SetVariable(pset.vars, "DBNAME", NULL);
+	SetVariable(pset.vars, "SERVICE", NULL);
 	SetVariable(pset.vars, "USER", NULL);
 	SetVariable(pset.vars, "HOST", NULL);
 	SetVariable(pset.vars, "PORT", NULL);
diff --git a/src/bin/psql/prompt.c b/src/bin/psql/prompt.c
index 0d99d00ac9..de3d976103 100644
--- a/src/bin/psql/prompt.c
+++ b/src/bin/psql/prompt.c
@@ -33,6 +33,7 @@
  * %p - backend pid
  * %> - database server port number
  * %n - database user name
+ * %s - service
  * %/ - current database
  * %~ - like %/ but "~" when database name equals user name
  * %w - whitespace of the same width as the most recent output of PROMPT1
@@ -246,6 +247,11 @@ get_prompt(promptStatus_t status, ConditionalStack cstack)
 						}
 					break;
 
+				case 's':
+					if (PQservice(pset.db))
+						strlcpy(buf, PQservice(pset.db), sizeof(buf));
+					break;
+
 				case 'l':
 					snprintf(buf, sizeof(buf), UINT64_FORMAT, pset.stmt_lineno);
 					break;
-- 
2.39.5


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