refactor main loop into multiple functions
This also gains the ability to report errors when posting the response
This commit is contained in:
parent
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A7B62D657EF764F8
395
src/lambda.zig
395
src/lambda.zig
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@ -5,11 +5,21 @@ const HandlerFn = *const fn (std.mem.Allocator, []const u8) anyerror![]const u8;
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const log = std.log.scoped(.lambda);
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var empty_headers: std.http.Headers = undefined;
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var client: ?std.http.Client = null;
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const prefix = "http://";
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const postfix = "/2018-06-01/runtime/invocation";
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pub fn deinit() void {
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if (client) |*c| c.deinit();
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client = null;
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}
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/// Starts the lambda framework. Handler will be called when an event is processing
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/// If an allocator is not provided, an approrpriate allocator will be selected and used
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/// This function is intended to loop infinitely. If not used in this manner,
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/// make sure to call the deinit() function
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pub fn run(allocator: ?std.mem.Allocator, event_handler: HandlerFn) !void { // TODO: remove inferred error set?
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const prefix = "http://";
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const postfix = "/2018-06-01/runtime/invocation";
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const lambda_runtime_uri = std.os.getenv("AWS_LAMBDA_RUNTIME_API") orelse test_lambda_runtime_uri.?;
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// TODO: If this is null, go into single use command line mode
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@ -21,9 +31,13 @@ pub fn run(allocator: ?std.mem.Allocator, event_handler: HandlerFn) !void { // T
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defer alloc.free(url);
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const uri = try std.Uri.parse(url);
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var client: std.http.Client = .{ .allocator = alloc };
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defer client.deinit();
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var empty_headers = std.http.Headers.init(alloc);
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// TODO: Simply adding this line without even using the client is enough
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// to cause seg faults!?
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// client = client orelse .{ .allocator = alloc };
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// so we'll do this instead
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if (client != null) return error.MustDeInitBeforeCallingRunAgain;
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client = .{ .allocator = alloc };
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empty_headers = std.http.Headers.init(alloc);
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defer empty_headers.deinit();
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log.info("tid {d} (lambda): Bootstrap initializing with event url: {s}", .{ std.Thread.getCurrentId(), url });
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@ -36,160 +50,229 @@ pub fn run(allocator: ?std.mem.Allocator, event_handler: HandlerFn) !void { // T
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var req_alloc = std.heap.ArenaAllocator.init(alloc);
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defer req_alloc.deinit();
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const req_allocator = req_alloc.allocator();
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var req = try client.request(.GET, uri, empty_headers, .{});
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defer req.deinit();
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req.start() catch |err| { // Well, at this point all we can do is shout at the void
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log.err("Get fail (start): {}", .{err});
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std.os.exit(0);
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// Fundamentally we're doing 3 things:
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// 1. Get the next event from Lambda (event data and request id)
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// 2. Call our handler to get the response
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// 3. Post the response back to Lambda
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var ev = getEvent(req_allocator, uri) catch |err| {
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// Well, at this point all we can do is shout at the void
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log.err("Error fetching event details: {}", .{err});
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std.os.exit(1);
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// continue;
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};
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if (ev == null) continue; // this gets logged in getEvent, and without
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// a request id, we still can't do anything
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// reasonable to report back
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const event = ev.?;
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defer ev.?.deinit();
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const event_response = event_handler(req_allocator, event.event_data) catch |err| {
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event.reportError(@errorReturnTrace(), err, lambda_runtime_uri) catch unreachable;
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continue;
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};
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// Lambda freezes the process at this line of code. During warm start,
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// the process will unfreeze and data will be sent in response to client.get
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req.wait() catch |err| { // Well, at this point all we can do is shout at the void
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log.err("Get fail (wait): {}", .{err});
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std.os.exit(0);
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event.postResponse(lambda_runtime_uri, event_response) catch |err| {
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event.reportError(@errorReturnTrace(), err, lambda_runtime_uri) catch unreachable;
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continue;
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};
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}
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}
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const Event = struct {
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allocator: std.mem.Allocator,
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event_data: []u8,
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request_id: []u8,
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const Self = @This();
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pub fn init(allocator: std.mem.Allocator, event_data: []u8, request_id: []u8) Self {
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return .{
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.allocator = allocator,
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.event_data = event_data,
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.request_id = request_id,
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};
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}
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pub fn deinit(self: *Self) void {
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self.allocator.free(self.event_data);
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self.allocator.free(self.request_id);
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}
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fn reportError(
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self: Self,
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return_trace: ?*std.builtin.StackTrace,
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err: anytype,
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lambda_runtime_uri: []const u8,
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) !void {
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// If we fail in this function, we're pretty hosed up
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if (return_trace) |rt|
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log.err("Caught error: {}. Return Trace: {any}", .{ err, rt })
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else
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log.err("Caught error: {}. No return trace available", .{err});
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const err_url = try std.fmt.allocPrint(
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self.allocator,
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"{s}{s}{s}/{s}/error",
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.{ prefix, lambda_runtime_uri, postfix, self.request_id },
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);
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defer self.allocator.free(err_url);
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const err_uri = try std.Uri.parse(err_url);
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const content =
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\\{{
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\\ "errorMessage": "{s}",
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\\ "errorType": "HandlerReturnedError",
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\\ "stackTrace": [ "{any}" ]
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\\}}
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;
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const content_fmt = if (return_trace) |rt|
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try std.fmt.allocPrint(self.allocator, content, .{ @errorName(err), rt })
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else
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try std.fmt.allocPrint(self.allocator, content, .{ @errorName(err), "no return trace available" });
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defer self.allocator.free(content_fmt);
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log.err("Posting to {s}: Data {s}", .{ err_url, content_fmt });
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var err_headers = std.http.Headers.init(self.allocator);
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defer err_headers.deinit();
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err_headers.append(
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"Lambda-Runtime-Function-Error-Type",
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"HandlerReturned",
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) catch |append_err| {
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log.err("Error appending error header to post response for request id {s}: {}", .{ self.request_id, append_err });
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std.os.exit(1);
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};
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// TODO: There is something up with using a shared client in this way
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// so we're taking a perf hit in favor of stability. In a practical
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// sense, without making HTTPS connections (lambda environment is
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// non-ssl), this shouldn't be a big issue
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var cl = std.http.Client{ .allocator = self.allocator };
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defer cl.deinit();
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var req = try cl.request(.POST, err_uri, empty_headers, .{});
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// var req = try client.?.request(.POST, err_uri, empty_headers, .{});
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// defer req.deinit();
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req.transfer_encoding = .{ .content_length = content_fmt.len };
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req.start() catch |post_err| { // Well, at this point all we can do is shout at the void
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log.err("Error posting response (start) for request id {s}: {}", .{ self.request_id, post_err });
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std.os.exit(1);
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};
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try req.writeAll(content_fmt);
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try req.finish();
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req.wait() catch |post_err| { // Well, at this point all we can do is shout at the void
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log.err("Error posting response (wait) for request id {s}: {}", .{ self.request_id, post_err });
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std.os.exit(1);
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};
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// TODO: Determine why this post is not returning
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if (req.response.status != .ok) {
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// Documentation says something about "exit immediately". The
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// Lambda infrastrucutre restarts, so it's unclear if that's necessary.
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// It seems as though a continue should be fine, and slightly faster
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// std.os.exit(1);
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log.err("Get fail: {} {s}", .{
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@intFromEnum(req.response.status),
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req.response.status.phrase() orelse "",
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});
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continue;
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std.os.exit(1);
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}
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var request_id: ?[]const u8 = null;
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var content_length: ?usize = null;
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for (req.response.headers.list.items) |h| {
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if (std.ascii.eqlIgnoreCase(h.name, "Lambda-Runtime-Aws-Request-Id"))
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request_id = h.value;
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if (std.ascii.eqlIgnoreCase(h.name, "Content-Length")) {
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content_length = std.fmt.parseUnsigned(usize, h.value, 10) catch null;
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if (content_length == null)
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log.warn("Error parsing content length value: '{s}'", .{h.value});
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}
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// TODO: XRay uses an environment variable to do its magic. It's our
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// responsibility to set this, but no zig-native setenv(3)/putenv(3)
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// exists. I would kind of rather not link in libc for this,
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// so we'll hold for now and think on this
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// if (std.mem.indexOf(u8, h.name.value, "Lambda-Runtime-Trace-Id")) |_|
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// std.process.
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// std.os.setenv("AWS_LAMBDA_RUNTIME_API");
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}
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if (request_id == null) {
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// We can't report back an issue because the runtime error reporting endpoint
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// uses request id in its path. So the best we can do is log the error and move
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// on here.
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log.err("Could not find request id: skipping request", .{});
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continue;
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}
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const req_id = request_id.?;
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log.debug("got lambda request with id {s}", .{req_id});
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const reader = req.reader();
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var buf: [65535]u8 = undefined;
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var resp_payload = std.ArrayList(u8).init(req_allocator);
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if (content_length) |len| {
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resp_payload.ensureTotalCapacity(len) catch {
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log.err("Could not allocate memory for body of request id: {s}", .{request_id.?});
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continue;
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};
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}
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defer resp_payload.deinit();
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while (true) {
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const read = try reader.read(&buf);
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try resp_payload.appendSlice(buf[0..read]);
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if (read == 0) break;
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}
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const event_response = event_handler(req_allocator, resp_payload.items) catch |err| {
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// Stack trace will return null if stripped
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const return_trace = @errorReturnTrace();
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if (return_trace) |rt|
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log.err("Caught error: {}. Return Trace: {any}", .{ err, rt })
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else
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log.err("Caught error: {}. No return trace available", .{err});
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const err_url = try std.fmt.allocPrint(req_allocator, "{s}{s}/runtime/invocation/{s}/error", .{ prefix, lambda_runtime_uri, req_id });
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defer req_allocator.free(err_url);
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const err_uri = try std.Uri.parse(err_url);
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const content =
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\\ {s}
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\\ "errorMessage": "{s}",
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\\ "errorType": "HandlerReturnedError",
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\\ "stackTrace": [ "{any}" ]
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\\ {s}
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;
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const content_fmt = if (return_trace) |rt|
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try std.fmt.allocPrint(req_allocator, content, .{ "{", @errorName(err), rt, "}" })
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else
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try std.fmt.allocPrint(req_allocator, content, .{ "{", @errorName(err), "no return trace available", "}" });
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defer req_allocator.free(content_fmt);
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log.err("Posting to {s}: Data {s}", .{ err_url, content_fmt });
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var err_headers = std.http.Headers.init(req_allocator);
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defer err_headers.deinit();
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err_headers.append(
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"Lambda-Runtime-Function-Error-Type",
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"HandlerReturned",
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) catch |append_err| {
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log.err("Error appending error header to post response for request id {s}: {}", .{ req_id, append_err });
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std.os.exit(0);
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continue;
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};
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var err_req = try client.request(.POST, err_uri, empty_headers, .{});
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defer err_req.deinit();
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err_req.start() catch |post_err| { // Well, at this point all we can do is shout at the void
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log.err("Error posting response for request id {s}: {}", .{ req_id, post_err });
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std.os.exit(0);
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continue;
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};
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err_req.wait() catch |post_err| { // Well, at this point all we can do is shout at the void
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log.err("Error posting response for request id {s}: {}", .{ req_id, post_err });
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std.os.exit(0);
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continue;
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};
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// TODO: Determine why this post is not returning
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if (err_req.response.status != .ok) {
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// Documentation says something about "exit immediately". The
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// Lambda infrastrucutre restarts, so it's unclear if that's necessary.
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// It seems as though a continue should be fine, and slightly faster
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// std.os.exit(1);
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log.err("Get fail: {} {s}", .{
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@intFromEnum(err_req.response.status),
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err_req.response.status.phrase() orelse "",
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});
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continue;
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}
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log.err("Post complete", .{});
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continue;
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};
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// TODO: We should catch these potential alloc errors too
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// TODO: This whole loop should be in another function so we can catch everything at once
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const response_url = try std.fmt.allocPrint(req_allocator, "{s}{s}{s}/{s}/response", .{ prefix, lambda_runtime_uri, postfix, req_id });
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defer req_allocator.free(response_url);
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const response_uri = try std.Uri.parse(response_url);
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const response_content = try std.fmt.allocPrint(req_allocator, "{s} \"content\": \"{s}\" {s}", .{ "{", event_response, "}" });
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var resp_req = try client.request(.POST, response_uri, empty_headers, .{});
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defer resp_req.deinit();
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resp_req.transfer_encoding = .{ .content_length = response_content.len };
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try resp_req.start();
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try resp_req.writeAll(response_content); // TODO: AllocPrint + writeAll makes no sense
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try resp_req.finish();
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resp_req.wait() catch |err| {
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// TODO: report error
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log.err("Error posting response for request id {s}: {}", .{ req_id, err });
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continue;
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};
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log.err("Error reporting post complete", .{});
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}
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fn postResponse(self: Self, lambda_runtime_uri: []const u8, event_response: []const u8) !void {
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const response_url = try std.fmt.allocPrint(
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self.allocator,
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"{s}{s}{s}/{s}/response",
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.{ prefix, lambda_runtime_uri, postfix, self.request_id },
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);
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defer self.allocator.free(response_url);
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const response_uri = try std.Uri.parse(response_url);
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var cl = std.http.Client{ .allocator = self.allocator };
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defer cl.deinit();
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var req = try cl.request(.POST, response_uri, empty_headers, .{});
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// var req = try client.?.request(.POST, response_uri, empty_headers, .{});
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defer req.deinit();
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const response_content = try std.fmt.allocPrint(
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self.allocator,
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"{{ \"content\": \"{s}\" }}",
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.{event_response},
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);
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defer self.allocator.free(response_content);
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req.transfer_encoding = .{ .content_length = response_content.len };
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try req.start();
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try req.writeAll(response_content);
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try req.finish();
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try req.wait();
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}
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};
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fn getEvent(allocator: std.mem.Allocator, event_data_uri: std.Uri) !?Event {
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// TODO: There is something up with using a shared client in this way
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// so we're taking a perf hit in favor of stability. In a practical
|
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// sense, without making HTTPS connections (lambda environment is
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// non-ssl), this shouldn't be a big issue
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var cl = std.http.Client{ .allocator = allocator };
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defer cl.deinit();
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var req = try cl.request(.GET, event_data_uri, empty_headers, .{});
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// var req = try client.?.request(.GET, event_data_uri, empty_headers, .{});
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// defer req.deinit();
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try req.start();
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try req.finish();
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// Lambda freezes the process at this line of code. During warm start,
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// the process will unfreeze and data will be sent in response to client.get
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try req.wait();
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if (req.response.status != .ok) {
|
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// Documentation says something about "exit immediately". The
|
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// Lambda infrastrucutre restarts, so it's unclear if that's necessary.
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// It seems as though a continue should be fine, and slightly faster
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// std.os.exit(1);
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log.err("Lambda server event response returned bad error code: {} {s}", .{
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@intFromEnum(req.response.status),
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req.response.status.phrase() orelse "",
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});
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return error.EventResponseNotOkResponse;
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}
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var request_id: ?[]const u8 = null;
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var content_length: ?usize = null;
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for (req.response.headers.list.items) |h| {
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if (std.ascii.eqlIgnoreCase(h.name, "Lambda-Runtime-Aws-Request-Id"))
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request_id = h.value;
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if (std.ascii.eqlIgnoreCase(h.name, "Content-Length")) {
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content_length = std.fmt.parseUnsigned(usize, h.value, 10) catch null;
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if (content_length == null)
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log.warn("Error parsing content length value: '{s}'", .{h.value});
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}
|
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// TODO: XRay uses an environment variable to do its magic. It's our
|
||||
// responsibility to set this, but no zig-native setenv(3)/putenv(3)
|
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// exists. I would kind of rather not link in libc for this,
|
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// so we'll hold for now and think on this
|
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// if (std.mem.indexOf(u8, h.name.value, "Lambda-Runtime-Trace-Id")) |_|
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// std.process.
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// std.os.setenv("AWS_LAMBDA_RUNTIME_API");
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}
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if (request_id == null) {
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// We can't report back an issue because the runtime error reporting endpoint
|
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// uses request id in its path. So the best we can do is log the error and move
|
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// on here.
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log.err("Could not find request id: skipping request", .{});
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return null;
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}
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if (content_length == null) {
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// We can't report back an issue because the runtime error reporting endpoint
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// uses request id in its path. So the best we can do is log the error and move
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// on here.
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log.err("No content length provided for event data", .{});
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return null;
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}
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const req_id = request_id.?;
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log.debug("got lambda request with id {s}", .{req_id});
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var resp_payload = try std.ArrayList(u8).initCapacity(allocator, content_length.?);
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defer resp_payload.deinit();
|
||||
try resp_payload.resize(content_length.?);
|
||||
var response_data = try resp_payload.toOwnedSlice();
|
||||
errdefer allocator.free(response_data);
|
||||
_ = try req.readAll(response_data);
|
||||
|
||||
return Event.init(
|
||||
allocator,
|
||||
response_data,
|
||||
try allocator.dupe(u8, req_id),
|
||||
);
|
||||
}
|
||||
|
||||
////////////////////////////////////////////////////////////////////////
|
||||
|
|
@ -320,7 +403,7 @@ fn test_run(allocator: std.mem.Allocator, event_handler: HandlerFn) !std.Thread
|
|||
);
|
||||
}
|
||||
|
||||
fn lambda_request(allocator: std.mem.Allocator, request: []const u8) ![]u8 {
|
||||
fn lambda_request(allocator: std.mem.Allocator, request: []const u8, request_count: usize) ![]u8 {
|
||||
var arena = std.heap.ArenaAllocator.init(allocator);
|
||||
defer arena.deinit();
|
||||
var aa = arena.allocator();
|
||||
|
|
@ -344,7 +427,7 @@ fn lambda_request(allocator: std.mem.Allocator, request: []const u8) ![]u8 {
|
|||
// booleans to know when to shut down. This function is designed for a
|
||||
// single request/response pair only
|
||||
|
||||
lambda_remaining_requests = 1; // in case anyone messed with this, we will make sure we start
|
||||
lambda_remaining_requests = request_count;
|
||||
server_remaining_requests = lambda_remaining_requests.? * 2; // Lambda functions
|
||||
// fetch from the server,
|
||||
// then post back. Always
|
||||
|
|
@ -379,7 +462,25 @@ test "basic request" {
|
|||
const expected_response =
|
||||
\\{ "content": "{"foo": "bar", "baz": "qux"}" }
|
||||
;
|
||||
const lambda_response = try lambda_request(allocator, request);
|
||||
const lambda_response = try lambda_request(allocator, request, 1);
|
||||
defer deinit();
|
||||
defer allocator.free(lambda_response);
|
||||
try std.testing.expectEqualStrings(expected_response, lambda_response);
|
||||
}
|
||||
|
||||
test "several requests do not fail" {
|
||||
// std.testing.log_level = .debug;
|
||||
const allocator = std.testing.allocator;
|
||||
const request =
|
||||
\\{"foo": "bar", "baz": "qux"}
|
||||
;
|
||||
|
||||
// This is what's actually coming back. Is this right?
|
||||
const expected_response =
|
||||
\\{ "content": "{"foo": "bar", "baz": "qux"}" }
|
||||
;
|
||||
const lambda_response = try lambda_request(allocator, request, 5);
|
||||
defer deinit();
|
||||
defer allocator.free(lambda_response);
|
||||
try std.testing.expectEqualStrings(expected_response, lambda_response);
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user