Add GET /health endpoint for monitoring

lib/App/Yath/Server/Plack.pm

@@ -201,6 +201,11 @@ sub handle_request {
     my $self = shift;
     my ($env) = @_;
 
+    # Health check endpoint — bypass routing, sessions, and auth
+    if ($env->{PATH_INFO} eq '/health' && ($env->{REQUEST_METHOD} || '') eq 'GET') {
+        return $self->_health_check();
+    }
+
     my $schema = $self->schema;
     my $router           = $self->router;
     my $route            = $router->match($env) || {};
@@ -304,6 +309,31 @@ sub handle_request {
 }
 
 
+sub _health_check {
+    my $self = shift;
+
+    my ($ok, $error);
+    eval {
+        my $dbh = $self->schema->storage->dbh;
+        $ok = $dbh->ping ? 1 : 0;
+        $error = "DB ping returned false" unless $ok;
+        1;
+    } or do {
+        $ok = 0;
+        $error = "$@";
+        chomp $error;
+    };
+
+    my $status = $ok ? 200 : 503;
+    my $body   = $ok ? {ok => 1} : {ok => 0, error => $error};
+
+    my $res = resp($status);
+    $res->content_type('application/json');
+    $res->body(encode_json($body));
+    return $res->finalize;
+}
+
+
 __END__
 
 =pod

t/unit/App/Yath/Server/Plack.t

@@ -1,5 +1,143 @@
-use Test2::V0 -target => 'App::Yath::Server::Plack';
+use Test2::V0;
 
-skip_all "write me";
+BEGIN {
+    my $ok = eval { require App::Yath::Server::Plack; 1 };
+    skip_all "Server dependencies not installed" unless $ok;
+}
+
+use Test2::Harness::Util::JSON qw/decode_json/;
+use App::Yath::Server::Plack;
+
+subtest '_health_check returns 200 when DB ping succeeds' => sub {
+    my $mock_dbh = mock {} => (
+        add => [ping => sub { 1 }],
+    );
+    my $mock_storage = mock {} => (
+        add => [dbh => sub { $mock_dbh }],
+    );
+    my $mock_schema = mock {} => (
+        add => [
+            storage => sub { $mock_storage },
+            config  => sub { 0 },
+        ],
+    );
+    my $mock_config = mock {} => (
+        add => [schema => sub { $mock_schema }],
+    );
+
+    my $plack = App::Yath::Server::Plack->new(schema_config => $mock_config);
+
+    my $env = {
+        PATH_INFO      => '/health',
+        REQUEST_METHOD => 'GET',
+    };
+    my $result = $plack->handle_request($env);
+
+    is($result->[0], 200, 'status is 200');
+
+    my $body = join('', @{$result->[2]});
+    my $data = decode_json($body);
+    is($data, {ok => 1}, 'body contains ok => 1');
+};
+
+subtest '_health_check returns 503 when DB ping fails' => sub {
+    my $mock_dbh = mock {} => (
+        add => [ping => sub { 0 }],
+    );
+    my $mock_storage = mock {} => (
+        add => [dbh => sub { $mock_dbh }],
+    );
+    my $mock_schema = mock {} => (
+        add => [
+            storage => sub { $mock_storage },
+            config  => sub { 0 },
+        ],
+    );
+    my $mock_config = mock {} => (
+        add => [schema => sub { $mock_schema }],
+    );
+
+    my $plack = App::Yath::Server::Plack->new(schema_config => $mock_config);
+
+    my $env = {
+        PATH_INFO      => '/health',
+        REQUEST_METHOD => 'GET',
+    };
+    my $result = $plack->handle_request($env);
+
+    is($result->[0], 503, 'status is 503');
+
+    my $body = join('', @{$result->[2]});
+    my $data = decode_json($body);
+    is($data->{ok}, 0, 'ok is 0');
+    like($data->{error}, qr/ping/, 'error mentions ping');
+};
+
+subtest '_health_check returns 503 when DB connection throws' => sub {
+    my $mock_storage = mock {} => (
+        add => [dbh => sub { die "Connection refused\n" }],
+    );
+    my $mock_schema = mock {} => (
+        add => [
+            storage => sub { $mock_storage },
+            config  => sub { 0 },
+        ],
+    );
+    my $mock_config = mock {} => (
+        add => [schema => sub { $mock_schema }],
+    );
+
+    my $plack = App::Yath::Server::Plack->new(schema_config => $mock_config);
+
+    my $env = {
+        PATH_INFO      => '/health',
+        REQUEST_METHOD => 'GET',
+    };
+    my $result = $plack->handle_request($env);
+
+    is($result->[0], 503, 'status is 503');
+
+    my $body = join('', @{$result->[2]});
+    my $data = decode_json($body);
+    is($data->{ok}, 0, 'ok is 0');
+    like($data->{error}, qr/Connection refused/, 'error captures exception message');
+};
+
+subtest '/health only responds to GET' => sub {
+    my $health_called = 0;
+    my $mock_dbh = mock {} => (
+        add => [ping => sub { $health_called++; 1 }],
+    );
+    my $mock_storage = mock {} => (
+        add => [dbh => sub { $mock_dbh }],
+    );
+    my $mock_schema = mock {} => (
+        add => [
+            storage => sub { $mock_storage },
+            config  => sub { 0 },
+        ],
+    );
+    my $mock_config = mock {} => (
+        add => [schema => sub { $mock_schema }],
+    );
+
+    my $plack = App::Yath::Server::Plack->new(schema_config => $mock_config);
+
+    # GET /health should trigger the health check
+    my $get_result = $plack->handle_request({
+        PATH_INFO      => '/health',
+        REQUEST_METHOD => 'GET',
+    });
+    is($get_result->[0], 200, 'GET /health returns 200');
+    is($health_called, 1, 'health check was invoked for GET');
+
+    # POST /health should NOT trigger the health check — it falls through
+    $health_called = 0;
+    my $post_result = eval { $plack->handle_request({
+        PATH_INFO      => '/health',
+        REQUEST_METHOD => 'POST',
+    }) };
+    is($health_called, 0, 'health check was NOT invoked for POST');
+};
 
 done_testing;