[PATCH 3/5] clone|fetch|--mirror: add convenience $INBOX_DIR/Makefile

[Eric Wong <e@80x24.org>]

Since the beginning of time, I've been dropping Makefiles
in $INBOX_DIR (and above hiearchies) to organize groups
of commands.

make(1) is widely available in various flavors and a familiar
tool for our target audience.  It is easy to run in the right
directory, typically has built-in shell completion, and doesn't
silently ignore errors by default like Bourne shell.
---
 lib/PublicInbox/Fetch.pm     |  3 +-
 lib/PublicInbox/LeiMirror.pm | 61 +++++++++++++++++++++++++++++++++++-
 t/lei-mirror.t               |  2 ++
 3 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/Fetch.pm b/lib/PublicInbox/Fetch.pm
index 0539fe50..184b4f26 100644
--- a/lib/PublicInbox/Fetch.pm
+++ b/lib/PublicInbox/Fetch.pm
@@ -91,7 +91,7 @@ sub get_fingerprint2 {
 	Digest::SHA::sha256(do { local $/; <$rd> });
 }
 
-sub do_fetch {
+sub do_fetch { # main entry point
 	my ($cls, $lei, $cd) = @_;
 	my $ibx_ver;
 	$lei->{curl} //= PublicInbox::LeiCurl->new($lei) or return;
@@ -124,6 +124,7 @@ Unable to infer inbox URL from <$git_url>
 EOM
 		$ibx_uri = URI->new($inbox_url);
 	}
+	PublicInbox::LeiMirror::write_makefile($dir, $ibx_ver);
 	$lei->qerr("# inbox URL: $ibx_uri/");
 	my $res = do_manifest($lei, $dir, $ibx_uri) or return;
 	my ($code, $v1_path, $v2_epochs, $muri, $ft, $mf) = @$res;
diff --git a/lib/PublicInbox/LeiMirror.pm b/lib/PublicInbox/LeiMirror.pm
index c113c9de..749c6b7d 100644
--- a/lib/PublicInbox/LeiMirror.pm
+++ b/lib/PublicInbox/LeiMirror.pm
@@ -9,7 +9,7 @@ use parent qw(PublicInbox::IPC);
 use IO::Uncompress::Gunzip qw(gunzip $GunzipError);
 use PublicInbox::Spawn qw(popen_rd spawn run_die);
 use File::Temp ();
-use Fcntl qw(SEEK_SET);
+use Fcntl qw(SEEK_SET O_CREAT O_EXCL O_WRONLY);
 
 sub do_finish_mirror { # dwaitpid callback
 	my ($arg, $pid) = @_;
@@ -201,6 +201,7 @@ sub clone_v1 {
 	my $cerr = run_reap($lei, $cmd, $opt);
 	return $lei->child_error($cerr, "@$cmd failed") if $cerr;
 	_try_config($self);
+	write_makefile($self->{dst}, 1);
 	index_cloned_inbox($self, 1);
 }
 
@@ -234,6 +235,7 @@ failed to extract epoch number from $src
 	my $mg = PublicInbox::MultiGit->new($dst, 'all.git', 'git');
 	$mg->fill_alternates;
 	for my $i ($mg->git_epochs) { $mg->epoch_cfg_set($i) }
+	write_makefile($self->{dst}, 2);
 	undef $on_destroy; # unlock
 	index_cloned_inbox($self, 2);
 }
@@ -356,4 +358,61 @@ sub ipc_atfork_child {
 	$self->SUPER::ipc_atfork_child;
 }
 
+sub write_makefile {
+	my ($dir, $ibx_ver) = @_;
+	my $f = "$dir/Makefile";
+	if (sysopen my $fh, $f, O_CREAT|O_EXCL|O_WRONLY) {
+		print $fh <<EOM or die "print($f) $!";
+# This is a v$ibx_ver public-inbox, see the public-inbox-v$ibx_ver-format(5)
+# manpage for more information on the format.  This Makefile is
+# intended as a familiar wrapper for users unfamiliar with
+# public-inbox-* commands.
+#
+# See the respective manpages for public-inbox-fetch(1),
+# public-inbox-index(1), etc for more information on
+# some of the commands used by this Makefile.
+#
+# This Makefile will not modified nor read by public-inbox,
+# so you may edit it freely with your own convenience targets
+# and notes.  public-inbox-fetch will recreate it if removed.
+EOM
+		print $fh <<'EOM' or die "print($f): $!";
+# the default target:
+help :
+	@echo Common targets:
+	@echo '    make fetch        - fetch from remote git repostorie(s)'
+	@echo '    make update       - fetch and update index '
+	@echo
+	@echo Rarely needed targets:
+	@echo '    make reindex      - may be needed for new features/bugfixes'
+	@echo '    make compact      - rewrite Xapian storage to save space'
+
+fetch :
+	public-inbox-fetch
+update :
+	@if ! public-inbox-fetch --exit-code; \
+	then \
+		c=$$?; \
+		test $$c -eq 127 && exit 0; \
+		exit $$c; \
+	elif test -f msgmap.sqlite3 || test -f public-inbox/msgmap.sqlite3; \
+	then \
+		public-inbox-index; \
+	else \
+		echo 'public-inbox index not initialized'; \
+		echo 'see public-inbox-index(1) man page'; \
+	fi
+reindex :
+	public-inbox-index --reindex
+compact :
+	public-inbox-compact
+
+.PHONY : help fetch update reindex compact
+EOM
+		close $fh or die "close($f): $!";
+	} else {
+		die "open($f): $!" unless $!{EEXIST};
+	}
+}
+
 1;
diff --git a/t/lei-mirror.t b/t/lei-mirror.t
index 9fdda5aa..3eb7f36a 100644
--- a/t/lei-mirror.t
+++ b/t/lei-mirror.t
@@ -19,6 +19,7 @@ test_lei({ tmpdir => $tmpdir }, sub {
 	ok(-f "$t1/public-inbox/msgmap.sqlite3", 't1-mirror indexed');
 	is(PublicInbox::Inbox::try_cat("$t1/description"),
 		"mirror of $http/t1/\n", 'description set');
+	ok(-f "$t1/Makefile", 'convenience Makefile added (v1)');
 
 	lei_ok('ls-external');
 	like($lei_out, qr!\Q$t1\E!, 't1 added to ls-externals');
@@ -27,6 +28,7 @@ test_lei({ tmpdir => $tmpdir }, sub {
 	lei_ok('add-external', $t2, '--mirror', "$http/t2/", \'--mirror v2');
 	ok(-f "$t2/msgmap.sqlite3", 't2-mirror indexed');
 	ok(-f "$t2/description", 't2 description');
+	ok(-f "$t2/Makefile", 'convenience Makefile added (v2)');
 	is(PublicInbox::Inbox::try_cat("$t2/description"),
 		"mirror of $http/t2/\n", 'description set');