Output a | character in log message continuation lines

This makes it easier to tell where multi-line log messages begin and
end.

ChangeLog.md

@@ -38,6 +38,9 @@ repository history](https://github.com/ddclient/ddclient/commits/master).
     [#639](https://github.com/ddclient/ddclient/pull/639)
   * Updated sample systemd service unit file to improve logging in the systemd
     journal.  [#669](https://github.com/ddclient/ddclient/pull/669)
+  * The second and subsequent lines in a multi-line log message are now prefixed
+    with a `|` character.
+    [#676](https://github.com/ddclient/ddclient/pull/676)
 
 ### Bug fixes
 

ddclient.in

@@ -2398,14 +2398,15 @@ sub logmsg {
     chomp($buffer);
 
     my $prefix = $args{pfx};
-    $prefix = sprintf "%-9s ", $prefix if $prefix;
+    $prefix = sprintf "%-9s  ", $prefix if $prefix;
     if ($file) {
         $prefix .= "file $file";
         $prefix .= ", line $lineno" if $lineno;
-        $prefix .= ": ";
+        $prefix .= ":  ";
     }
     if ($prefix) {
         $buffer = "$prefix$buffer";
+        $prefix =~ s/  $/| /;
         $buffer =~ s/\n/\n$prefix/g;
     }
     $buffer .= "\n";

t/logmsg.pl

@@ -55,49 +55,49 @@ my @test_cases = (
     {
         desc => 'single-line prefix',
         args => [pfx => 'PFX:', 'foo'],
-        want => "PFX:      foo\n",
+        want => "PFX:       foo\n",
     },
     {
         desc => 'multi-line prefix',
         args => [pfx => 'PFX:', "foo\nbar"],
-        want => "PFX:      foo\nPFX:      bar\n",
+        want => "PFX:       foo\nPFX:     | bar\n",
     },
     {
         desc => 'single-line long prefix',
         args => [pfx => 'VERY LONG PREFIX:', 'foo'],
-        want => "VERY LONG PREFIX: foo\n",
+        want => "VERY LONG PREFIX:  foo\n",
     },
     {
         desc => 'multi-line long prefix',
         args => [pfx => 'VERY LONG PREFIX:', "foo\nbar"],
-        want => "VERY LONG PREFIX: foo\nVERY LONG PREFIX: bar\n",
+        want => "VERY LONG PREFIX:  foo\nVERY LONG PREFIX:| bar\n",
     },
     {
         desc => 'single line, no prefix, file',
         args => ['foo'],
         file => 'name',
-        want => "file name: foo\n",
+        want => "file name:  foo\n",
     },
     {
         desc => 'single line, no prefix, file, and line number',
         args => ['foo'],
         file => 'name',
         lineno => 42,
-        want => "file name, line 42: foo\n",
+        want => "file name, line 42:  foo\n",
     },
     {
         desc => 'single line, prefix, file, and line number',
         args => [pfx => 'PFX:', 'foo'],
         file => 'name',
         lineno => 42,
-        want => "PFX:      file name, line 42: foo\n",
+        want => "PFX:       file name, line 42:  foo\n",
     },
     {
         desc => 'multiple lines, prefix, file, and line number',
         args => [pfx => 'PFX:', "foo\nbar"],
         file => 'name',
         lineno => 42,
-        want => "PFX:      file name, line 42: foo\nPFX:      file name, line 42: bar\n",
+        want => "PFX:       file name, line 42:  foo\nPFX:       file name, line 42:| bar\n",
     },
 );