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get all response body data from executor without allocations in core

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This commit is contained in:
Emil Lerch 2023-05-12 17:10:30 -07:00
parent f57189fbfd
commit 5be44c911f
Signed by: lobo
GPG Key ID: A7B62D657EF764F8
3 changed files with 150 additions and 45 deletions
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1
build.zig
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@ -34,6 +34,7 @@ pub fn build(b: *std.Build) void {
.target = target,
.optimize = optimize,
});
lib.linkLibC();
// This declares intent for the executable to be installed into the
// standard location when the user invokes the "install" step (the default

34
src/main-lib.zig
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@ -1,12 +1,34 @@
const std = @import("std");
const testing = std.testing;
export fn serve() void {
const stdout_file = std.io.getStdOut().writer();
var bw = std.io.bufferedWriter(stdout_file);
const stdout = bw.writer();
stdout.print(" 2 ", .{}) catch unreachable;
bw.flush() catch unreachable;
const Response = extern struct {
ptr: [*]u8,
len: usize,
};
var child_allocator = std.heap.raw_c_allocator; // raw allocator recommended for use in arenas
var arena: std.heap.ArenaAllocator = undefined;
export fn handle_request() *Response {
arena = std.heap.ArenaAllocator.init(child_allocator);
var allocator = arena.allocator();
var al = std.ArrayList(u8).init(allocator);
var writer = al.writer();
writer.print(" 2.", .{}) catch unreachable;
// Cannot simply return &Blah. Need to assign to var first
var rc = &Response{
.ptr = al.items.ptr,
.len = al.items.len,
};
return rc;
}
/// having request_deinit allows for a general deinit as well
export fn request_deinit() void {
std.log.debug("deinit", .{});
arena.deinit();
}
export fn add(a: i32, b: i32) i32 {

160
src/main.zig
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@ -2,16 +2,29 @@ const std = @import("std");
const builtin = @import("builtin");
const Watch = @import("Watch.zig");
const serveFn = *const fn () void;
const serveFn = *const fn () *ServeReturn;
const requestDeinitFn = *const fn () void;
const timeout = 250;
const ServeReturn = extern struct {
ptr: [*]u8,
len: usize,
};
const FullReturn = struct {
response: []u8,
executor: *Executor,
};
const Executor = struct {
path: [:0]const u8,
library: ?*anyopaque = null,
serveFn: ?serveFn = null,
requestDeinitFn: ?requestDeinitFn = null,
watch: ?usize = null,
reload_lock: bool = false,
in_request_lock: bool = false,
};
var executors = [_]Executor{
@ -30,30 +43,58 @@ pub const std_options = struct {
.{ .scope = .watch, .level = .info },
};
};
const SERVE_FN_NAME = "serve";
const SERVE_FN_NAME = "handle_request";
const PORT = 8069;
fn serve() !void {
// TODO: writer as anytype is not going to survive across library boundaries...
fn serve(allocator: std.mem.Allocator, response: *std.http.Server.Response) !*FullReturn {
var null_server = std.http.Server.init(allocator, .{});
defer null_server.deinit();
var data: [14]u8 = @constCast(&[_]u8{0x00} ** 14).*;
var child_response = std.http.Server.Response{
.server = &null_server,
.request = response.request,
.connection = .{
.conn = .{
.stream = .{ .handle = 0 },
.protocol = .plain,
},
},
.address = .{ .any = .{
.data = data,
.family = 0,
} },
.headers = response.headers,
};
_ = child_response;
// if (some path routing thing) {
// TODO: Get request body into executor
// TODO: Get headers back from executor
// TODO: Get request headers into executor
const executor = try getExecutor(0);
executor.in_request_lock = true;
errdefer executor.in_request_lock = false;
// Call external library
var serve_result = executor.serveFn.?();
(try getExecutor(0))();
// if (inx > 4) {
// if (inx % 2 == 0)
// (try getExecutor(0))()
// else
// (try getExecutor(1))();
// }
// Deal with results
var slice: []u8 = serve_result.ptr[0..serve_result.len];
var rc = &FullReturn{
.executor = executor,
.response = slice,
};
return rc;
}
fn getExecutor(key: usize) !serveFn {
fn getExecutor(key: usize) !*Executor {
var executor = &executors[key];
if (executor.serveFn) |s| return s;
if (executor.serveFn != null) return executor;
executor.library = blk: {
if (executor.library) |l|
break :blk l;
while (executor.reload_lock) // system is reloading the library
std.time.sleep(1);
std.time.sleep(1 * std.time.ns_per_ms / 2);
if (executor.library) |l| // check again to see where we are at
break :blk l;
@ -71,9 +112,15 @@ fn getExecutor(key: usize) !serveFn {
if (serve_fn == null) return error.CouldNotLoadSymbolServe;
executor.serveFn = @ptrCast(serveFn, serve_fn.?);
return executor.serveFn.?;
loadOptionalSymbols(executor);
return executor;
}
fn loadOptionalSymbols(executor: *Executor) void {
if (std.c.dlsym(executor.library.?, "request_deinit")) |s| {
executor.requestDeinitFn = @ptrCast(requestDeinitFn, s);
}
}
fn executorChanged(watch: usize) void {
// NOTE: This will be called off the main thread
log.debug("executor with watch {d} changed", .{watch});
@ -81,6 +128,8 @@ fn executorChanged(watch: usize) void {
if (executor.watch) |w| {
if (w == watch) {
if (executor.library) |l| {
while (executor.in_request_lock)
std.time.sleep(1 * std.time.ns_per_ms / 2);
executor.reload_lock = true;
defer executor.reload_lock = false;
@ -91,13 +140,15 @@ fn executorChanged(watch: usize) void {
log.warn("could not reload! error opening library", .{});
return;
};
executor.serveFn = @ptrCast(serveFn, std.c.dlsym(executor.library.?, SERVE_FN_NAME));
if (executor.serveFn == null) {
var symbol = std.c.dlsym(executor.library.?, SERVE_FN_NAME);
if (symbol == null) {
log.warn("could not reload! error finding symbol", .{});
if (std.c.dlclose(executor.library.?) != 0)
@panic("System unstable: Error after library open and cannot close");
return;
}
executor.serveFn = @ptrCast(serveFn, symbol);
loadOptionalSymbols(executor);
}
}
}
@ -164,37 +215,68 @@ pub fn main() !void {
log.info("listening on port: {d}", .{server_port});
if (builtin.os.tag == .linux)
log.info("pid: {d}", .{std.os.linux.getpid()});
// install signal handler
var act = std.os.Sigaction{
.handler = .{ .sigaction = exitApplication },
.mask = std.os.empty_sigset,
.flags = (std.os.SA.SIGINFO | std.os.SA.RESTART | std.os.SA.RESETHAND),
};
try std.os.sigaction(std.os.SIG.INT, &act, null);
try std.os.sigaction(std.os.SIG.TERM, &act, null);
try installSignalHandler();
while (true) {
var arena = std.heap.ArenaAllocator.init(std.heap.c_allocator);
defer arena.deinit();
const res = try server.accept(.{ .dynamic = max_header_size });
defer res.deinit();
defer res.reset();
try res.wait();
const server_body: []const u8 = "message from server!\n";
res.transfer_encoding = .{ .content_length = server_body.len };
try res.headers.append("content-type", "text/plain");
try res.headers.append("connection", "close");
try res.do();
var buf: [128]u8 = undefined;
const n = try res.readAll(&buf);
_ = n;
_ = try res.writer().writeAll(server_body);
try res.finish();
processRequest(arena.allocator(), &server) catch |e| {
log.err("Unexpected error processing request: {any}", .{e});
if (@errorReturnTrace()) |trace| {
std.debug.dumpStackTrace(trace.*);
}
};
}
}
fn processRequest(allocator: std.mem.Allocator, server: *std.http.Server) !void {
const max_header_size = 8192;
const res = try server.accept(.{ .dynamic = max_header_size });
defer res.deinit();
defer res.reset();
try res.wait();
// TODO: deal with this
var buf: [1024]u8 = undefined;
const n = try res.readAll(&buf);
_ = n;
// TODO: we need to also have a defer statement to deinit whatever happens
// with the executor library. This will also add a race condition where
// we could have a memory leak if the executor reloads in the middle of a
// request. We may want to add a new spinlock on the reload thread to
// avoid reloading in the middle of a request, which would be generally
// bad anyway
const errstr = "Internal Server Error\n";
var errbuf: [errstr.len]u8 = undefined;
var response_bytes = try std.fmt.bufPrint(&errbuf, errstr, .{});
var full_response = serve(allocator, res) catch |e| brk: {
res.status = .internal_server_error;
// TODO: more about this particular request
log.err("Unexpected error from executor processing request: {any}", .{e});
if (@errorReturnTrace()) |trace| {
std.debug.dumpStackTrace(trace.*);
}
break :brk null;
};
defer {
if (full_response) |f| {
if (f.executor.requestDeinitFn) |d| d();
f.executor.in_request_lock = false;
}
}
if (full_response) |f|
response_bytes = f.response;
res.transfer_encoding = .{ .content_length = response_bytes.len };
try res.headers.append("content-type", "text/plain");
try res.headers.append("connection", "close");
try res.do();
_ = try res.writer().writeAll(response_bytes);
try res.finish();
}
test {
// To run nested container tests, either, call `refAllDecls` which will
// reference all declarations located in the given argument.