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package main
import (
"fmt"
"net/http"
"os"
"path/filepath"
"time"
)
// =============================================================================
// hosty hello — example app + tree generator
// =============================================================================
func cmdHello(args []string) error {
if len(args) == 0 {
printHelloUsage()
return fmt.Errorf("subcommand required")
}
switch args[0] {
case "run-v1":
return cmdHelloServeV1()
case "run-v2":
return cmdHelloServeV2()
case "-h", "--help", "help":
printHelloUsage()
return nil
default:
fmt.Fprintf(os.Stderr, "hosty hello: unknown subcommand %q\n\n", args[0])
printHelloUsage()
os.Exit(1)
}
return nil
}
func printHelloUsage() {
fmt.Print(`Usage: hosty hello <subcommand>
Subcommands:
run-v1 Run the v0.1 HTTP server (visit counter only)
Requires: HOSTY_DB, HOSTY_PORT
Optional: HOSTY_FS (appends to visits.log, serves GET /log)
GREETING (response prefix, default: "Hello from hosty!")
run-v2 Run the v0.2 HTTP server (visit counter + last_visited timestamp)
Runs a DB migration on first start (adds last_visited column via PRAGMA user_version)
Requires: HOSTY_DB, HOSTY_PORT
Optional: HOSTY_FS (appends to visits.log, serves GET /log)
GREETING (response prefix, default: "Hello from hosty!")
To build a hosty-hello image:
hosty pack -name hosty-hello -version 0.1 \
-map /path/to/hosty:usr/bin/hosty \
-ExecStart "/usr/bin/hosty hello run-v1" \
-config "GREETING:Greeting message shown on GET /:optional,default=Hello from hosty!"
`)
}
// helloEnv reads and validates HOSTY_DB and HOSTY_PORT from the environment.
// HOSTY_FS is optional; fsDir is empty string if not set.
// GREETING is optional; defaults to "Hello from hosty!".
func helloEnv() (dbPath, port, fsDir, greeting string, err error) {
dbPath = os.Getenv("HOSTY_DB")
if dbPath == "" {
return "", "", "", "", fmt.Errorf("HOSTY_DB environment variable not set")
}
port = os.Getenv("HOSTY_PORT")
if port == "" {
return "", "", "", "", fmt.Errorf("HOSTY_PORT environment variable not set")
}
fsDir = os.Getenv("HOSTY_FS")
greeting = os.Getenv("GREETING")
if greeting == "" {
greeting = "Hello from hosty!"
}
return dbPath, port, fsDir, greeting, nil
}
// helloAppendVisit appends a line to <fsDir>/visits.log recording the visit
// count and current time. Silently does nothing if fsDir is empty.
func helloAppendVisit(fsDir string, count int) {
if fsDir == "" {
return
}
f, err := os.OpenFile(
filepath.Join(fsDir, "visits.log"),
os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644,
)
if err != nil {
fmt.Fprintf(os.Stderr, "hosty hello: open visits.log: %v\n", err)
return
}
defer f.Close()
ts := time.Now().UTC().Format("2006-01-02 15:04:05")
fmt.Fprintf(f, "visit #%d at %s\n", count, ts)
}
// cmdHelloServeV1 runs the v0.1 HTTP server: plain visit counter, no migrations.
func cmdHelloServeV1() error {
dbPath, port, fsDir, greeting, err := helloEnv()
if err != nil {
return err
}
db, err := openDB(dbPath)
if err != nil {
return fmt.Errorf("opening db: %w", err)
}
defer db.Close()
_, err = db.Exec(`
CREATE TABLE IF NOT EXISTS visits (
id INTEGER PRIMARY KEY CHECK (id = 1),
count INTEGER NOT NULL DEFAULT 0
);
INSERT OR IGNORE INTO visits (id, count) VALUES (1, 0);
`)
if err != nil {
return fmt.Errorf("init visits table: %w", err)
}
mux := http.NewServeMux()
mux.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
fmt.Fprint(w, "ok")
})
mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
var count int
err := db.QueryRow(`
UPDATE visits SET count = count + 1 WHERE id = 1
RETURNING count
`).Scan(&count)
if err != nil {
http.Error(w, fmt.Sprintf("db error: %v", err), http.StatusInternalServerError)
return
}
helloAppendVisit(fsDir, count)
w.Header().Set("Content-Type", "text/plain")
fmt.Fprintf(w, "%s Visit #%d\n", greeting, count)
})
mux.HandleFunc("/log", func(w http.ResponseWriter, r *http.Request) {
if fsDir == "" {
http.Error(w, "HOSTY_FS not set", http.StatusNotFound)
return
}
data, err := os.ReadFile(filepath.Join(fsDir, "visits.log"))
if err != nil {
http.Error(w, fmt.Sprintf("read log: %v", err), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "text/plain")
w.Write(data)
})
addr := ":" + port
fmt.Fprintf(os.Stderr, "hosty hello v0.1: listening on %s\n", addr)
return http.ListenAndServe(addr, mux)
}
// cmdHelloServeV2 runs the v0.2 HTTP server: visit counter with last_visited
// timestamp. Runs a DB migration on first start (schema version 0 → 1).
func cmdHelloServeV2() error {
dbPath, port, fsDir, greeting, err := helloEnv()
if err != nil {
return err
}
db, err := openDB(dbPath)
if err != nil {
return fmt.Errorf("opening db: %w", err)
}
defer db.Close()
// Create base table (idempotent, same as v0.1).
_, err = db.Exec(`
CREATE TABLE IF NOT EXISTS visits (
id INTEGER PRIMARY KEY CHECK (id = 1),
count INTEGER NOT NULL DEFAULT 0
);
INSERT OR IGNORE INTO visits (id, count) VALUES (1, 0);
`)
if err != nil {
return fmt.Errorf("init visits table: %w", err)
}
// Run pending migrations using PRAGMA user_version as the schema version.
var schemaVersion int
if err := db.QueryRow(`PRAGMA user_version`).Scan(&schemaVersion); err != nil {
return fmt.Errorf("reading schema version: %w", err)
}
if schemaVersion < 1 {
fmt.Fprintf(os.Stderr, "hosty hello: migrating schema 0 → 1 (adding last_visited column)\n")
if _, err := db.Exec(`ALTER TABLE visits ADD COLUMN last_visited TEXT`); err != nil {
return fmt.Errorf("migration 0→1: %w", err)
}
if _, err := db.Exec(`PRAGMA user_version = 1`); err != nil {
return fmt.Errorf("setting schema version: %w", err)
}
fmt.Fprintf(os.Stderr, "hosty hello: migration complete, schema is now version 1\n")
}
mux := http.NewServeMux()
mux.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
fmt.Fprint(w, "ok")
})
mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
var count int
var lastVisited string
err := db.QueryRow(`
UPDATE visits SET count = count + 1, last_visited = datetime('now')
WHERE id = 1
RETURNING count, last_visited
`).Scan(&count, &lastVisited)
if err != nil {
http.Error(w, fmt.Sprintf("db error: %v", err), http.StatusInternalServerError)
return
}
helloAppendVisit(fsDir, count)
w.Header().Set("Content-Type", "text/plain")
fmt.Fprintf(w, "%s Visit #%d (last visited: %s)\n", greeting, count, lastVisited)
})
mux.HandleFunc("/log", func(w http.ResponseWriter, r *http.Request) {
if fsDir == "" {
http.Error(w, "HOSTY_FS not set", http.StatusNotFound)
return
}
data, err := os.ReadFile(filepath.Join(fsDir, "visits.log"))
if err != nil {
http.Error(w, fmt.Sprintf("read log: %v", err), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "text/plain")
w.Write(data)
})
addr := ":" + port
fmt.Fprintf(os.Stderr, "hosty hello v0.2: listening on %s\n", addr)
return http.ListenAndServe(addr, mux)
}
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