add file watcher
This commit is contained in:
parent
08dec6a978
commit
5e09b735c6
GPG Key ID:
A7B62D657EF764F8
|
|
@ -24,6 +24,8 @@ pub fn build(b: *std.Build) void {
|
|||
.optimize = optimize,
|
||||
});
|
||||
|
||||
exe.linkLibC();
|
||||
|
||||
const lib = b.addSharedLibrary(.{
|
||||
.name = "faas-proxy-sample-lib",
|
||||
// In this case the main source file is merely a path, however, in more
|
||||
|
|
@ -60,6 +62,9 @@ pub fn build(b: *std.Build) void {
|
|||
run_cmd.addArgs(args);
|
||||
}
|
||||
|
||||
const run_step = b.step("run", "Run the app");
|
||||
run_step.dependOn(&run_cmd.step);
|
||||
|
||||
// Creates a step for unit testing. This only builds the test executable
|
||||
// but does not run it.
|
||||
const main_tests = b.addTest(.{
|
||||
|
|
|
|||
126
src/Watch.zig
Normal file
126
src/Watch.zig
Normal file
|
|
@ -0,0 +1,126 @@
|
|||
const builtin = @import("builtin");
|
||||
const std = @import("std");
|
||||
const c = @cImport({
|
||||
@cInclude("poll.h");
|
||||
});
|
||||
|
||||
const MAX_FDS = 1024;
|
||||
|
||||
const Self = @This();
|
||||
|
||||
fileChanged: *const fn (usize) void,
|
||||
inotify_fd: ?std.os.fd_t = null,
|
||||
// sizeof(std.os.pollfd) == 8, so this is 8k
|
||||
// fds: [MAX_FDS]std.os.pollfd = [_]std.os.pollfd{.{ .fd = 0, .events = 0, .revents = 0 }} ** MAX_FDS,
|
||||
nfds_t: usize = 0,
|
||||
wds: [MAX_FDS]i32 = [_]i32{0} ** MAX_FDS,
|
||||
modified: [MAX_FDS]bool = [_]bool{false} ** MAX_FDS,
|
||||
|
||||
pub fn init(file_changed: *const fn (usize) void) Self {
|
||||
if (builtin.os.tag != .linux)
|
||||
@compileError("Unsupported OS");
|
||||
return .{
|
||||
.fileChanged = file_changed,
|
||||
};
|
||||
}
|
||||
|
||||
pub fn deinit(self: *Self) void {
|
||||
if (self.inotify_fd) |fd| {
|
||||
for (self.wds) |wd| {
|
||||
const rc = std.os.linux.inotify_rm_watch(fd, wd);
|
||||
// Errno can only be EBADF, EINVAL if either the inotify fs or the wd are invalid
|
||||
std.debug.assert(rc == 0);
|
||||
}
|
||||
std.os.close(fd);
|
||||
}
|
||||
}
|
||||
|
||||
pub fn watchFds(self: *Self) void {
|
||||
while (true) {
|
||||
if (self.nfds_t == 0) {
|
||||
std.time.sleep(250);
|
||||
continue;
|
||||
}
|
||||
var fds = &[_]std.os.pollfd{.{ .fd = self.inotify_fd.?, .events = c.POLLIN, .revents = 0 }};
|
||||
// NOTE: There is a std.io.poll that provides a higher level abstraction.
|
||||
// However, this API is strictly related to the use case of an open stream
|
||||
// for which we are awaiting data. In this case, we are polling for
|
||||
// an inotify event, for which no abstraction currently exists
|
||||
//
|
||||
// std.fs.watch looks really good...but it requires event based I/O,
|
||||
// which is not yet ready to be (re)added.
|
||||
if ((std.os.poll(
|
||||
fds,
|
||||
-1, // Infinite timeout
|
||||
) catch @panic("poll error")) > 0) {
|
||||
if (fds[0].revents & c.POLLIN == c.POLLIN) { // POLLIN means "there is data to read"
|
||||
var event_buf: [4096]u8 align(@alignOf(std.os.linux.inotify_event)) = undefined;
|
||||
// "borrowed" from https://ziglang.org/documentation/master/std/src/std/fs/watch.zig.html#L588
|
||||
const bytes_read = std.os.read(self.inotify_fd.?, &event_buf) catch unreachable;
|
||||
|
||||
var ptr: [*]u8 = &event_buf;
|
||||
const end_ptr = ptr + bytes_read;
|
||||
while (@ptrToInt(ptr) < @ptrToInt(end_ptr)) {
|
||||
const ev = @ptrCast(
|
||||
*const std.os.linux.inotify_event,
|
||||
@alignCast(@alignOf(*const std.os.linux.inotify_event), ptr),
|
||||
);
|
||||
|
||||
if (ev.mask & std.os.linux.IN.MODIFY == std.os.linux.IN.MODIFY) {
|
||||
for (self.wds, 0..) |wd, inx| {
|
||||
if (ev.wd == wd)
|
||||
self.modified[inx] = true;
|
||||
}
|
||||
}
|
||||
// attrib added as build process moves in place and modifies attributes
|
||||
// TODO: Also watch MOVED_TO, which is on the directory...
|
||||
if (ev.mask & std.os.linux.IN.CLOSE_WRITE == std.os.linux.IN.CLOSE_WRITE or
|
||||
ev.mask & std.os.linux.IN.ATTRIB == std.os.linux.IN.ATTRIB)
|
||||
{
|
||||
for (self.wds, 0..) |wd, inx| {
|
||||
if (ev.wd == wd)
|
||||
self.fileChanged(inx);
|
||||
}
|
||||
}
|
||||
if (ev.mask & std.os.linux.IN.CLOSE_NOWRITE == std.os.linux.IN.CLOSE_NOWRITE) {
|
||||
for (self.wds, 0..) |wd, inx| {
|
||||
if (ev.wd == wd and self.modified[inx]) {
|
||||
self.modified[inx] = false;
|
||||
self.fileChanged(inx);
|
||||
}
|
||||
}
|
||||
}
|
||||
// see man 2 poll
|
||||
self.handleFile(fds[0]);
|
||||
ptr = @alignCast(
|
||||
@alignOf(std.os.linux.inotify_event),
|
||||
ptr + @sizeOf(std.os.linux.inotify_event) + ev.len,
|
||||
);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub fn addFileWatch(self: *Self, path: [:0]const u8) !usize {
|
||||
self.inotify_fd = self.inotify_fd orelse try std.os.inotify_init1(std.os.linux.IN.NONBLOCK);
|
||||
errdefer {
|
||||
std.os.close(self.inotify_fd.?);
|
||||
self.inotify_fd = null;
|
||||
}
|
||||
// open 20, close_norite 10, attrib 4
|
||||
self.wds[self.nfds_t] = try std.os.inotify_add_watchZ(
|
||||
self.inotify_fd.?,
|
||||
path,
|
||||
std.os.linux.IN.ATTRIB | std.os.linux.IN.CLOSE | std.os.linux.IN.CLOSE_WRITE | std.os.linux.IN.MODIFY,
|
||||
);
|
||||
if (self.wds[self.nfds_t] == -1)
|
||||
@panic("could not set watch");
|
||||
self.nfds_t += 1;
|
||||
return self.nfds_t - 1;
|
||||
}
|
||||
|
||||
fn handleFile(self: Self, fd: std.os.pollfd) void {
|
||||
_ = fd;
|
||||
_ = self;
|
||||
}
|
||||
|
|
@ -1,6 +1,14 @@
|
|||
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(" 3 ", .{}) catch unreachable;
|
||||
bw.flush() catch unreachable;
|
||||
}
|
||||
|
||||
export fn add(a: i32, b: i32) i32 {
|
||||
return a + b;
|
||||
}
|
||||
|
|
|
|||
140
src/main.zig
140
src/main.zig
|
|
@ -1,8 +1,125 @@
|
|||
const std = @import("std");
|
||||
const c = @cImport({
|
||||
@cInclude("dlfcn.h");
|
||||
});
|
||||
|
||||
const Watch = @import("Watch.zig");
|
||||
const serve_op = *const fn () void;
|
||||
|
||||
var shutdown = false;
|
||||
const timeout = 250;
|
||||
|
||||
const Executor = struct {
|
||||
path: [:0]const u8,
|
||||
library: ?*anyopaque = null,
|
||||
serve: ?serve_op = null,
|
||||
watch: ?usize = null,
|
||||
};
|
||||
|
||||
var executors = [_]Executor{.{
|
||||
.path = "/home/lobo/home/faas-proxy/zig-out/lib/libfaas-proxy-sample-lib.so",
|
||||
}};
|
||||
|
||||
var watcher = Watch.init(executorChanged);
|
||||
|
||||
fn serve() !void {
|
||||
// if (some path routing thing) {
|
||||
|
||||
(try getExecutor(0))();
|
||||
// if (std.c.dlerror()) |_| { // TODO: use capture
|
||||
// return error.CouldNotLoadSymbolServe;
|
||||
// }
|
||||
// TODO: only close on reload
|
||||
// if (std.c.dlclose(library.?) != 0) {
|
||||
// return error.CouldNotUnloadLibrary;
|
||||
// }
|
||||
// library = null;
|
||||
// }
|
||||
}
|
||||
fn getExecutor(key: usize) !serve_op {
|
||||
var executor = &executors[key];
|
||||
if (executor.serve) |s| return s;
|
||||
|
||||
executor.library = blk: {
|
||||
if (executor.library) |l| {
|
||||
break :blk l;
|
||||
}
|
||||
const l = try dlopen(executor.path);
|
||||
errdefer if (std.c.dlclose(l) != 0)
|
||||
@panic("System unstable: Error after library open and cannot close");
|
||||
executor.watch = try watcher.addFileWatch(executor.path);
|
||||
break :blk l;
|
||||
};
|
||||
|
||||
// std.c.dlerror();
|
||||
const serve_function = std.c.dlsym(executor.library.?, "serve");
|
||||
if (serve_function == null) return error.CouldNotLoadSymbolServe;
|
||||
|
||||
executor.serve = @ptrCast(serve_op, serve_function.?);
|
||||
return executor.serve.?;
|
||||
}
|
||||
|
||||
// This works
|
||||
fn executorChanged(watch: usize) void {
|
||||
for (&executors) |*executor| {
|
||||
if (executor.watch) |w| {
|
||||
if (w == watch) {
|
||||
if (executor.library) |l| {
|
||||
// TODO: These two lines could introduce a race. Right now that would mean a panic
|
||||
executor.serve = null;
|
||||
if (std.c.dlclose(l) != 0)
|
||||
@panic("System unstable: Error after library open and cannot close");
|
||||
}
|
||||
executor.library = null;
|
||||
executor.serve = null;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// NOTE: this will be on a different thread. This code does not work, and I
|
||||
// am fairly certain it is because we can't share a function pointer between
|
||||
// threads
|
||||
// fn executorChanged(watch: usize) void {
|
||||
// std.debug.print("executor with watch {d} changed\n", .{watch});
|
||||
// for (&executors) |*executor| {
|
||||
// if (executor.watch) |w| {
|
||||
// if (w == watch) {
|
||||
// if (executor.library) |l| {
|
||||
// std.debug.print("reloading executor at path: {s}\n", .{executor.path});
|
||||
// const newlib = dlopen(executor.path) catch {
|
||||
// std.debug.print("could not reload! error opening library\n", .{});
|
||||
// return;
|
||||
// };
|
||||
// errdefer if (std.c.dlclose(newlib) != 0)
|
||||
// @panic("System unstable: Error after library open and cannot close");
|
||||
// const serve_function = std.c.dlsym(newlib, "serve");
|
||||
// if (serve_function == null) {
|
||||
// std.debug.print("could not reload! error finding symbol\n", .{});
|
||||
// return;
|
||||
// }
|
||||
// // new lib all loaded up - do the swap and close the old
|
||||
// std.debug.print("updating function and library\n", .{});
|
||||
// executor.serve = @ptrCast(serve_op, serve_function.?);
|
||||
// executor.library = newlib;
|
||||
// if (std.c.dlclose(l) != 0)
|
||||
// @panic("System unstable: Error after library open and cannot close");
|
||||
// std.debug.print("closed old library\n", .{});
|
||||
// }
|
||||
// }
|
||||
// }
|
||||
// }
|
||||
// }
|
||||
|
||||
fn dlopen(path: [:0]const u8) !*anyopaque {
|
||||
// We need now (and local) because we're about to call it
|
||||
const lib = std.c.dlopen(path, c.RTLD_NOW);
|
||||
if (lib) |l| return l;
|
||||
return error.CouldNotOpenDynamicLibrary;
|
||||
}
|
||||
|
||||
pub fn main() !void {
|
||||
// Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
|
||||
std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
|
||||
defer watcher.deinit();
|
||||
|
||||
// stdout is for the actual output of your application, for example if you
|
||||
// are implementing gzip, then only the compressed bytes should be sent to
|
||||
|
|
@ -11,9 +128,28 @@ pub fn main() !void {
|
|||
var bw = std.io.bufferedWriter(stdout_file);
|
||||
const stdout = bw.writer();
|
||||
|
||||
const stderr_file = std.io.getStdErr().writer();
|
||||
var bw_stderr = std.io.bufferedWriter(stderr_file);
|
||||
const stderr = bw_stderr.writer();
|
||||
|
||||
try stdout.print("Run `zig build test` to run the tests.\n", .{});
|
||||
|
||||
try bw.flush(); // don't forget to flush!
|
||||
const watcher_thread = try std.Thread.spawn(.{}, Watch.watchFds, .{&watcher});
|
||||
|
||||
while (true) {
|
||||
std.time.sleep(std.time.ns_per_s * 2);
|
||||
try stdout.print("Serving...", .{});
|
||||
try bw.flush();
|
||||
serve() catch |err| {
|
||||
try stderr.print("Error serving request ({any})\n", .{err});
|
||||
try bw_stderr.flush();
|
||||
};
|
||||
try stdout.print("served\n", .{});
|
||||
try bw.flush();
|
||||
}
|
||||
shutdown = true;
|
||||
watcher_thread.join();
|
||||
}
|
||||
|
||||
test "simple test" {
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user