cmd/stealthmountain: make the code easier to read

Signed-off-by: Xe Iaso <me@xeiaso.net>

13 files changed, 396 insertions, 0 deletions

diff --git a/cmd/_conferences/gceu23/README.md b/cmd/_conferences/gceu23/README.md
new file mode 100644
index 0000000..6f3abb8
--- /dev/null
+++ b/cmd/_conferences/gceu23/README.md
@@ -0,0 +1,34 @@
+# Reaching the Unix Philosophy's Logical Conclusion with WebAssembly
+
+Hey there! This is the example code I wrote for my talk at [GopherCon
+EU](https://gophercon.eu). This consists of a few folders with code:
+
+- `cmd`: Executable commands for the demo.
+- `cmd/aiyou`: The WebAssembly runner. It connects to `cmd/yuechu` and
+  exposes network connections as a filesystem. It is intended to run
+  `wasip1/echoclient.wasm`.
+- `cmd/yuechu`: The echo server that takes lines of inputs from
+  network connections and feeds them to WebAssembly modules then sends
+  the output back to the client. It runs `wasip1/promptreply.wasm` and
+  `wasip1/xesitemd.wasm`.
+- `wasip1`: A folder full of small demo programs. Each is built with
+  makefile commands.
+- `wasip1/echoclient.wasm`: A small Rust program that tries to connect
+  to the echo server, prompts for a line of input, prints what it got
+  back, and then exits.
+- `wasip1/promptreply.wasm`: A small Rust program that reads input
+  from standard in and then writes it to standard out.
+- `wasip1/xesitemd.wasm`: My [blog's](https://xeiaso.net) markdown to
+  HTML parser. It reads xesite-flavored markdown over standard input
+  and returns HTML over standard output.
+
+In order to build and run the code in this folder, you must be using
+Nix and be inside a `nix develop` shell. You can build most files in
+`wasip1` by using `make` such as like this:
+
+```
+make echoreply.wasm promptreply.wasm
+```
+
+If you have any questions, please [email
+me](https://xeiaso.net/contact) or open an issue on this repo.
diff --git a/cmd/_conferences/gceu23/cmd/aiyou/main.go b/cmd/_conferences/gceu23/cmd/aiyou/main.go
new file mode 100644
index 0000000..c36f428
--- /dev/null
+++ b/cmd/_conferences/gceu23/cmd/aiyou/main.go
@@ -0,0 +1,90 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io/fs"
+	"log"
+	"net"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
+	"within.website/x/internal"
+)
+
+var (
+	r    wazero.Runtime
+	code wazero.CompiledModule
+
+	binary = flag.String("wasm-binary", "./bin.wasm", "binary to run against every line of input from connections")
+)
+
+func main() {
+	internal.HandleStartup()
+	ctx := context.Background()
+
+	data, err := os.ReadFile(*binary)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	r = wazero.NewRuntime(ctx)
+
+	wasi_snapshot_preview1.MustInstantiate(ctx, r)
+
+	code, err = r.CompileModule(ctx, data)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	config := wazero.NewModuleConfig().
+		// OS stdio
+		WithStdout(os.Stdout).WithStdin(os.Stdin).WithStderr(os.Stderr).
+		// Placeholder argv[0]
+		WithArgs("aiyou").WithName("aiyou").
+		// Put network in /dev/net
+		WithFSConfig(wazero.NewFSConfig().WithFSMount(ConnFS{}, "/dev/"))
+
+	mod, err := r.InstantiateModule(ctx, code, config)
+	if err != nil {
+		log.Fatal(err)
+		return
+	}
+	defer mod.Close(ctx)
+}
+
+type ConnFS struct{}
+
+func (ConnFS) Open(name string) (fs.File, error) {
+	name = filepath.Base(name)
+	fmt.Println("connecting to", name)
+	conn, err := net.Dial("tcp", name)
+	if err != nil {
+		return nil, err
+	}
+
+	return ConnFile{Conn: conn}, nil
+}
+
+type ConnFile struct {
+	net.Conn
+}
+
+func (c ConnFile) Stat() (fs.FileInfo, error) {
+	return ConnFileInfo{c.Conn}, nil
+}
+
+type ConnFileInfo struct {
+	conn net.Conn
+}
+
+func (c ConnFileInfo) Name() string       { return c.conn.RemoteAddr().String() } // base name of the file
+func (c ConnFileInfo) Size() int64        { return 0 }                            // length in bytes for regular files; system-dependent for others
+func (c ConnFileInfo) Mode() fs.FileMode  { return 0 }                            // file mode bits
+func (c ConnFileInfo) ModTime() time.Time { return time.Now() }                   // modification time
+func (c ConnFileInfo) IsDir() bool        { return false }                        // abbreviation for Mode().IsDir()
+func (c ConnFileInfo) Sys() any           { return c.conn }                       // underlying data source (can return nil)
diff --git a/cmd/_conferences/gceu23/cmd/yuechu/main.go b/cmd/_conferences/gceu23/cmd/yuechu/main.go
new file mode 100644
index 0000000..b9798e9
--- /dev/null
+++ b/cmd/_conferences/gceu23/cmd/yuechu/main.go
@@ -0,0 +1,95 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"log/slog"
+	"math/rand"
+	"net"
+	"os"
+	"strconv"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
+	"within.website/x/internal"
+)
+
+var (
+	r    wazero.Runtime
+	code wazero.CompiledModule
+
+	binary = flag.String("wasm-binary", "./bin.wasm", "binary to run against every line of input from connections")
+	bind   = flag.String("bind", ":1997", "TCP host:port to bind on")
+)
+
+func main() {
+	internal.HandleStartup()
+	ctx := context.Background()
+
+	data, err := os.ReadFile(*binary)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	r = wazero.NewRuntime(ctx)
+
+	wasi_snapshot_preview1.MustInstantiate(ctx, r)
+
+	code, err = r.CompileModule(ctx, data)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	server, err := net.Listen("tcp", *bind)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	slog.Info("listening", "bind", *bind)
+
+	for {
+		conn, err := server.Accept()
+		if err != nil {
+			log.Println("Failed to accept conn.", err)
+			continue
+		}
+
+		fmt.Println(conn.RemoteAddr().String())
+
+		go func(conn net.Conn) {
+			defer func() {
+				fmt.Println("disconnect")
+				conn.Close()
+			}()
+
+			scn := bufio.NewScanner(conn)
+			scn.Split(bufio.ScanLines)
+
+			for scn.Scan() {
+				fout := &bytes.Buffer{}
+				fin := bytes.NewBuffer(scn.Bytes())
+
+				fmt.Println("<", fin.String())
+
+				name := strconv.Itoa(rand.Int())
+				config := wazero.NewModuleConfig().WithStdout(fout).WithStdin(fin).WithArgs("mastosan").WithName(name)
+
+				mod, err := r.InstantiateModule(ctx, code, config)
+				if err != nil {
+					slog.Error("can't instantiate module", "err", err, "remote_host", conn.RemoteAddr().String())
+					return
+				}
+				defer mod.Close(ctx)
+
+				fmt.Print(">", fout.String())
+
+				conn.Write(fout.Bytes())
+				conn.Close()
+			}
+		}(conn)
+	}
+}
diff --git a/cmd/_conferences/gceu23/diagram.dot b/cmd/_conferences/gceu23/diagram.dot
new file mode 100644
index 0000000..02dc327
--- /dev/null
+++ b/cmd/_conferences/gceu23/diagram.dot
@@ -0,0 +1,47 @@
+digraph G {
+    newrank=true;
+    graph [fontname = "Iosevka Aile Iaso"];
+    node [fontname = "Iosevka Aile Iaso"];
+    edge [fontname = "Iosevka Aile Iaso"];
+    
+    subgraph cluster_0 {
+        style=filled;
+        color=lightgrey;
+        node [style=filled,color=white];
+        label = "aiyou";
+        echoclient [label="echoclient.wasm"];
+        ConnFS;
+        connFile [label="connection"];
+    }
+
+    subgraph cluster_1 {
+        style=filled;
+        color=lightgrey;
+        node [style=filled,color=white];
+        label = "yuechu";
+        lis [label="net.Listener"];
+        conn [label="net.Conn"];
+        logger [label="ln.Logger"];
+        
+        subgraph cluster_2 {
+            style=filled;
+            color=grey;
+            node [style=filled,color=white];
+            label = "wasm program";
+            stdin;
+            stdout;
+            stderr;
+        }
+    }
+    
+    { rank=same; echoclient; lis; }
+    { rank=same; connFile; conn; }
+    
+    echoclient -> ConnFS [label="  mounted at /dev  "];
+    ConnFS -> connFile [label ="  opened to yuechu  "];
+    connFile -> lis [label = "TCP\nconnection"];
+    lis -> conn [label = "  accepted connection  "];
+    conn -> stdin [label = "input from\nuser"];
+    stdout -> conn [label = "  output from\nprogram"];
+    stderr -> logger [label = "error\nmessages"];
+}
diff --git a/cmd/_conferences/gceu23/wasip1/.gitignore b/cmd/_conferences/gceu23/wasip1/.gitignore
new file mode 100644
index 0000000..19e1bce
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/.gitignore
@@ -0,0 +1 @@
+*.wasm
diff --git a/cmd/_conferences/gceu23/wasip1/Makefile b/cmd/_conferences/gceu23/wasip1/Makefile
new file mode 100644
index 0000000..eed2dbd
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/Makefile
@@ -0,0 +1,15 @@
+GOBIN = gowasi
+
+export GOARCH = wasm
+export GOOS = wasip1
+
+SOURCES := $(wildcard *.go)
+OBJECTS := $(patsubst %.go, %.wasm, $(SOURCES))
+
+%.wasm: %.rs
+	rustc --target=wasm32-wasi $^
+
+%.wasm: %.go
+	$(GOBIN) build -o $@ $^
+
+all: $(OBJECTS)
diff --git a/cmd/_conferences/gceu23/wasip1/cat.go b/cmd/_conferences/gceu23/wasip1/cat.go
new file mode 100644
index 0000000..7033dbd
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/cat.go
@@ -0,0 +1,33 @@
+//go:build ignore
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+func main() {
+	flag.Usage = func() {
+		fmt.Printf("%s <file>\n\nprints file to standard out\n", os.Args[0])
+	}
+	flag.Parse()
+
+	if flag.NArg() != 1 {
+		log.Fatalf("wanted 1 arg, got %#v", os.Args)
+	}
+
+	fin, err := os.Open(flag.Arg(0))
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer fin.Close()
+
+	_, err = io.Copy(os.Stdout, fin)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/cmd/_conferences/gceu23/wasip1/echoclient.rs b/cmd/_conferences/gceu23/wasip1/echoclient.rs
new file mode 100644
index 0000000..4049203
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/echoclient.rs
@@ -0,0 +1,24 @@
+use std::{io, fs::File, str, thread, time};
+use std::io::prelude::*;
+
+fn main() -> io::Result<()> {
+    let stdin = io::stdin(); // We get `Stdin` here.
+    let mut fout = File::create("/dev/localhost:1997")?;
+    
+    print!("input>  ");
+    io::stdout().lock().flush()?;
+    let mut buf = String::new();
+    stdin.read_line(&mut buf)?;
+    write!(fout, "{}", buf)?;
+
+    let ten_millis = time::Duration::from_millis(10);
+    thread::sleep(ten_millis);
+
+    let mut buf = Vec::new();
+    fout.read_to_end(&mut buf)?;
+    let buf = unsafe { str::from_utf8_unchecked(&buf) };
+    print!("output> {}", buf);
+    io::stdout().lock().flush()?;
+
+    Ok(())
+}
diff --git a/cmd/_conferences/gceu23/wasip1/envdump.go b/cmd/_conferences/gceu23/wasip1/envdump.go
new file mode 100644
index 0000000..6f940c4
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/envdump.go
@@ -0,0 +1,18 @@
+//go:build ignore
+
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	if len(os.Environ()) == 0 {
+		fmt.Println("No environment variables found")
+		return
+	}
+	for _, kv := range os.Environ() {
+		fmt.Println(kv)
+	}
+}
diff --git a/cmd/_conferences/gceu23/wasip1/hello.go b/cmd/_conferences/gceu23/wasip1/hello.go
new file mode 100644
index 0000000..78a7f8f
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/hello.go
@@ -0,0 +1,9 @@
+//go:build ignore
+
+package main
+
+import "log"
+
+func main() {
+	log.Println("Hello, world!")
+}
diff --git a/cmd/_conferences/gceu23/wasip1/hello.rs b/cmd/_conferences/gceu23/wasip1/hello.rs
new file mode 100644
index 0000000..b4998a8
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/hello.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("hello, world!")
+}
diff --git a/cmd/_conferences/gceu23/wasip1/nihao.go b/cmd/_conferences/gceu23/wasip1/nihao.go
new file mode 100644
index 0000000..5a5c56e
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/nihao.go
@@ -0,0 +1,18 @@
+//go:build ignore
+
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+)
+
+func main() {
+	reader := bufio.NewReader(os.Stdin)
+	fmt.Print("你叫什么名字？")
+	os.Stdout.Sync()
+	名字, _ := reader.ReadString('\n')
+	fmt.Printf("你好%s!", strings.TrimSpace(名字))
+}
diff --git a/cmd/_conferences/gceu23/wasip1/promptreply.rs b/cmd/_conferences/gceu23/wasip1/promptreply.rs
new file mode 100644
index 0000000..09d29db
--- /dev/null
+++ b/cmd/_conferences/gceu23/wasip1/promptreply.rs
@@ -0,0 +1,9 @@
+use std::io;
+
+fn main() -> io::Result<()> {
+    let mut buffer = String::new();
+    let stdin = io::stdin(); // We get `Stdin` here.
+    stdin.read_line(&mut buffer)?;
+    println!("{}", buffer.trim());
+    Ok(())
+}