Print some basic server info to stderr

src/main.zig

@@ -1,27 +1,112 @@
 const std = @import("std");
 const zits = @import("zits");
+const clap = @import("clap");
+
+const SubCommands = enum {
+    help,
+    serve,
+    @"pub",
+};
+
+const main_parsers = .{
+    .command = clap.parsers.enumeration(SubCommands),
+};
+
+// The parameters for `main`. Parameters for the subcommands are specified further down.
+const main_params = clap.parseParamsComptime(
+    \\-h, --help  Display this help and exit.
+    \\<command>
+    \\
+);
+
+// To pass around arguments returned by clap, `clap.Result` and `clap.ResultEx` can be used to
+// get the return type of `clap.parse` and `clap.parseEx`.
+const MainArgs = clap.ResultEx(clap.Help, &main_params, main_parsers);
 
 pub fn main() !void {
-    // Prints to stderr, ignoring potential errors.
+    var dba = std.heap.DebugAllocator(.{}){};
-    std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
+    defer _ = dba.deinit();
-    try zits.bufferedPrint();
+    const gpa = dba.allocator();
-}
 
-test "simple test" {
+    var iter = try std.process.ArgIterator.initWithAllocator(gpa);
-    const gpa = std.testing.allocator;
+    defer iter.deinit();
-    var list: std.ArrayList(i32) = .empty;
-    defer list.deinit(gpa); // Try commenting this out and see if zig detects the memory leak!
-    try list.append(gpa, 42);
-    try std.testing.expectEqual(@as(i32, 42), list.pop());
-}
 
-test "fuzz example" {
+    _ = iter.next();
-    const Context = struct {
+
-        fn testOne(context: @This(), input: []const u8) anyerror!void {
+    var diag = clap.Diagnostic{};
-            _ = context;
+    var res = clap.parseEx(clap.Help, &main_params, main_parsers, &iter, .{
-            // Try passing `--fuzz` to `zig build test` and see if it manages to fail this test case!
+        .diagnostic = &diag,
-            try std.testing.expect(!std.mem.eql(u8, "canyoufindme", input));
+        .allocator = gpa,
-        }
+
+        // Terminate the parsing of arguments after parsing the first positional (0 is passed
+        // here because parsed positionals are, like slices and arrays, indexed starting at 0).
+        //
+        // This will terminate the parsing after parsing the subcommand enum and leave `iter`
+        // not fully consumed. It can then be reused to parse the arguments for subcommands.
+        .terminating_positional = 0,
+    }) catch |err| {
+        try diag.reportToFile(.stderr(), err);
+        return err;
     };
-    try std.testing.fuzz(Context{}, Context.testOne, .{});
+    defer res.deinit();
+
+    if (res.args.help != 0)
+        return clap.helpToFile(.stderr(), clap.Help, &main_params, .{});
+
+    const command = res.positionals[0] orelse return error.MissingCommand;
+    switch (command) {
+        .help => return clap.helpToFile(.stderr(), clap.Help, &main_params, .{}),
+        .serve => try serverMain(gpa, &iter, res),
+        .@"pub" => unreachable,
+    }
+}
+
+const ServerInfo = struct {
+    /// The unique identifier of the NATS server.
+    server_id: []const u8,
+    /// The name of the NATS server.
+    server_name: []const u8,
+    /// The version of NATS.
+    version: []const u8,
+    /// The version of golang the NATS server was built with.
+    go: []const u8 = "0.0.0",
+    /// The IP address used to start the NATS server,
+    /// by default this will be 0.0.0.0 and can be
+    /// configured with -client_advertise host:port.
+    host: []const u8 = "0.0.0.0",
+    /// The port number the NATS server is configured
+    /// to listen on.
+    port: u16 = 6868,
+    /// Whether the server supports headers.
+    headers: bool = false,
+    /// Maximum payload size, in bytes, that the server
+    /// will accept from the client.
+    max_payload: u64,
+    /// An integer indicating the protocol version of
+    /// the server. The server version 1.2.0 sets this
+    /// to 1 to indicate that it supports the "Echo"
+    /// feature.
+    proto: u32 = 1,
+};
+
+fn serverMain(gpa: std.mem.Allocator, iter: *std.process.ArgIterator, main_args: MainArgs) !void {
+    _ = gpa;
+    _ = iter;
+    _ = main_args;
+
+    const info: ServerInfo = .{
+        .server_id = "foo",
+        .server_name = "bar",
+        .version = "6.9.0",
+        .max_payload = 6969,
+    };
+
+    var out_fs = std.fs.File.stderr().writer(&.{});
+    const out = &out_fs.interface;
+
+    try std.json.Stringify.value(info, .{
+        .whitespace = .indent_2,
+    }, out);
+
+    std.debug.print("in serverMain\n", .{});
 }