libpq: Add "servicefile" connection option

This commit adds the possibility to specify a service file in a
connection string, using a new option called "servicefile".  The parsing
of the service file happens so as things are done in this order of
priority:
- The servicefile connection option.
- Environment variable PGSERVICEFILE.
- Default path, depending on the HOME environment.

Note that in the last default case, we need to fill in "servicefile" for
the connection's PQconninfoOption to let clients know which service file
has been used for the connection.  Some TAP tests are added, with a few
tweaks required for Windows when using URIs or connection option values,
for the location paths.

Author: Torsten Förtsch <tfoertsch123@gmail.com>
Co-authored-by: Ryo Kanbayashi <kanbayashi.dev@gmail.com>
Discussion: https://postgr.es/m/CAKkG4_nCjx3a_F3gyXHSPWxD8Sd8URaM89wey7fG_9g7KBkOCQ@mail.gmail.com

1 files changed, 17 insertions, 7 deletions

diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index b2c2cf9eac8..5bf59a19855 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -2320,6 +2320,19 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
       </listitem>
      </varlistentry>
 
+     <varlistentry id="libpq-connect-servicefile" xreflabel="servicefile">
+      <term><literal>servicefile</literal></term>
+      <listitem>
+       <para>
+        This option specifies the name of the per-user connection service file
+        (see <xref linkend="libpq-pgservice"/>).
+        Defaults to <filename>~/.pg_service.conf</filename>, or
+        <filename>%APPDATA%\postgresql\.pg_service.conf</filename> on
+        Microsoft Windows.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="libpq-connect-target-session-attrs" xreflabel="target_session_attrs">
       <term><literal>target_session_attrs</literal></term>
       <listitem>
@@ -9140,12 +9153,8 @@ myEventProc(PGEventId evtId, void *evtInfo, void *passThrough)
       <indexterm>
        <primary><envar>PGSERVICEFILE</envar></primary>
       </indexterm>
-      <envar>PGSERVICEFILE</envar> specifies the name of the per-user
-      connection service file
-      (see <xref linkend="libpq-pgservice"/>).
-      Defaults to <filename>~/.pg_service.conf</filename>, or
-      <filename>%APPDATA%\postgresql\.pg_service.conf</filename> on
-      Microsoft Windows.
+      <envar>PGSERVICEFILE</envar> behaves the same as the
+      <xref linkend="libpq-connect-servicefile"/> connection parameter.
      </para>
     </listitem>
 
@@ -9576,7 +9585,8 @@ myEventProc(PGEventId evtId, void *evtInfo, void *passThrough)
    On Microsoft Windows, it is named
    <filename>%APPDATA%\postgresql\.pg_service.conf</filename> (where
    <filename>%APPDATA%</filename> refers to the Application Data subdirectory
-   in the user's profile).  A different file name can be specified by
+   in the user's profile).  A different file name can be specified using the
+   <literal>servicefile</literal> key word in a libpq connection string or by
    setting the environment variable <envar>PGSERVICEFILE</envar>.
    The system-wide file is named <filename>pg_service.conf</filename>.
    By default it is sought in the <filename>etc</filename> directory