From bdb813c521819bfa2d7a50a6be546f2dddb1bc2b Mon Sep 17 00:00:00 2001
From: Bob Farrell <git@bob.frl>
Date: Thu, 15 Feb 2024 21:40:21 +0000
Subject: [PATCH] Dump stack trace on internal server error

Provide stack trace for debugging runtime errors in debug builds
---
 README.md                  |  6 +++++-
 src/jetzig/http/Server.zig | 20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 25e347a..1fee1ba 100644
--- a/README.md
+++ b/README.md
@@ -28,9 +28,9 @@ If you are interested in _Jetzig_ you will probably find these tools interesting
 * :white_check_mark: Error handling.
 * :white_check_mark: Static content from /public directory.
 * :white_check_mark: Headers (available but not yet wrapped).
+* :white_check_mark: Stack trace output on error.
 * :x: Static content generation (nearly there!).
 * :x: Param/JSON payload parsing/abstracting.
-* :x: Development-mode responses for debugging.
 * :x: Environment configurations (develompent/production/etc.)
 * :x: Middleware extensions (for e.g. authentication).
 * :x: Email delivery.
@@ -45,3 +45,7 @@ If you are interested in _Jetzig_ you will probably find these tools interesting
 ## LICENSE
 
 [MIT](LICENSE)
+
+## Contributors
+
+* [Bob Farrell](https://github.com/bobf)
diff --git a/src/jetzig/http/Server.zig b/src/jetzig/http/Server.zig
index 3d93bd9..8a85c2e 100644
--- a/src/jetzig/http/Server.zig
+++ b/src/jetzig/http/Server.zig
@@ -292,16 +292,34 @@ fn isUnhandledError(err: anyerror) bool {
 }
 
 fn internalServerError(self: *Self, request: *jetzig.http.Request, err: anyerror) !RenderedView {
-    _ = self;
     request.response_data.reset();
+
     var object = try request.response_data.object();
     try object.put("error", request.response_data.string(@errorName(err)));
 
+    const stack = @errorReturnTrace();
+    if (stack) |capture| try self.logStackTrace(capture, request, object);
+
     return .{
         .view = jetzig.views.View{ .data = request.response_data, .status_code = .internal_server_error },
         .content = "Internal Server Error\n",
     };
 }
+fn logStackTrace(
+    self: *Self,
+    stack: *std.builtin.StackTrace,
+    request: *jetzig.http.Request,
+    object: *jetzig.data.Value,
+) !void {
+    _ = self;
+    std.debug.print("\nStack Trace:\n{}", .{stack});
+    var array = std.ArrayList(u8).init(request.allocator);
+    const writer = array.writer();
+    try stack.format("", .{}, writer);
+    // TODO: Generate an array of objects with stack trace in useful data structure instead of
+    // dumping the whole formatted backtrace as a JSON string:
+    try object.put("backtrace", request.response_data.string(array.items));
+}
 
 fn requestLogMessage(self: *Self, request: *jetzig.http.Request, result: jetzig.caches.Result) ![]const u8 {
     const status: jetzig.http.status_codes.TaggedStatusCode = switch (result.value.status_code) {