add "Run your own ziglang.org/download mirror" docs

Signed-off-by: Stephen Gutekanst <[email protected]>

README.md

@@ -83,3 +83,40 @@ This will give you a URL you can visit to add the bot to your server.
 2. Download release binary, rename to `.exe`
 3. Place at `C:/wrench.exe` or some other location. Put on PATH if desired.
 4. In admin terminal run `wrench.exe setup`
+
+## Run your own ziglang.org/download mirror
+
+If you want to mirror https://ziglang.org/download on-demand, similar to what https://pkg.machengine.org does,
+you may do so using e.g. this `config.toml` with `Mode = "zig"` which disables all other Wrench functionality so it only mirrors Zig downloads:
+
+```toml
+# Note: data will be written in a directory relative to this config file.
+Mode = "zig"
+
+# HTTP configuration
+ExternalURL = "http://foobar.com"
+Address = ":80"
+
+# HTTPS configuration (optional, uses LetsEncrypt)
+#ExternalURL = "https://foobar.com"
+#Address = ":443"
+#LetsEncryptEmail = "[email protected]"
+```
+
+Wrench will save data relative to that config file, so generally you should put that `config.toml` into e.g. a `wrench/` directory somewhere.
+
+Running `wrench svc run` will start the server. Then you can fetch e.g.:
+
+* http://localhost/
+* http://localhost/zig/zig-linux-x86_64-0.13.0.tar.xz
+* http://localhost/zig/index.json - a strict superset of https://ziglang.org/download/index.json
+
+Downloads like http://localhost/zig/zig-linux-x86_64-0.13.0.tar.xz will be fetched on-demand from ziglang.org and then cached on the local filesystem forever after that.
+
+http://localhost/zig/index.json is like https://ziglang.org/download/index.json with some small differences:
+
+* It is fetched from ziglang.org once every 15 minutes and cached in-memory.
+* Entries from https://machengine.org/zig/index.json are added so the index.json _additionally_ contains Mach [nominated Zig versions](https://machengine.org/about/nominated-zig/)
+* `tarball` fields are rewritten to point to the configured `ExternalURL`
+
+If you want to run Wrench as a system service, have it auto-start after reboot, etc. then you can e.g. put the config file in `/root/wrench/config.toml`, run `wrench svc install` as root to install the systemd service, use `wrench svc start` to start the service, and `wrench svc status` to see the status and log file locations.

internal/wrench/bot.go

@@ -45,6 +45,9 @@ func (b *Bot) loadConfig() error {
 			return errors.New("expected Config or ConfigFile to be specified")
 		}
 		b.Config = &Config{}
+		if absPath, err := filepath.Abs(b.ConfigFile); err == nil {
+			b.logf("loading config file: %s", absPath)
+		}
 		return LoadConfig(b.ConfigFile, b.Config)
 	}
 	return nil
@@ -120,7 +123,7 @@ func (b *Bot) run(s service.Service) error {
 	}
 
 	if b.Config.Runner == "" {
-		if !b.Config.PkgProxy {
+		if b.Config.ModeType() == ModeWrench {
 			b.store, err = OpenStore(filepath.Join(b.Config.WrenchDir, "wrench.db") + "?_pragma=busy_timeout%3d10000")
 			if err != nil {
 				return errors.Wrap(err, "OpenStore")
@@ -135,7 +138,7 @@ func (b *Bot) run(s service.Service) error {
 		if err := b.httpStart(); err != nil {
 			return errors.Wrap(err, "http")
 		}
-		if !b.Config.PkgProxy {
+		if b.Config.ModeType() == ModeWrench {
 			if err := b.schedulerStart(); err != nil {
 				return errors.Wrap(err, "scheduler")
 			}

internal/wrench/config.go

@@ -9,6 +9,14 @@ import (
 	"github.com/hexops/wrench/internal/wrench/api"
 )
 
+type ModeType string
+
+const (
+	ModeWrench ModeType = "wrench"
+	ModePkg    ModeType = "pkg"
+	ModeZig    ModeType = "zig"
+)
+
 type Config struct {
 	// ExternalURL where Wrench is hosted, if any.
 	ExternalURL string
@@ -21,61 +29,97 @@ type Config struct {
 	// Act as a Zig package proxy like pkg.machengine.org, instead of as a regular wrench server.
 	PkgProxy bool `toml:"PkgProxy,omitempty"`
 
+	// Mode to operate in, one of:
+	//
+	// * "wrench" -> https://wrench.machengine.org - custom CI system, etc.
+	// * "pkg" -> https://pkg.machengine.org - package mirror and Zig download mirror
+	// * "zig" -> Zig download mirror only (subset of pkg.machengine.org)
+	Mode string `toml:"Mode,omitempty"`
+
+	// (optional) Directory for caching LetsEncrypt certificates
+	LetsEncryptCacheDir string `toml:"LetsEncryptCacheDir,omitempty"`
+
+	// (optional) Email to use for LetsEncrypt notifications
+	LetsEncryptEmail string `toml:"LetsEncryptEmail,omitempty"`
+
+	// Where Wrench should store its data, cofiguration, etc. Defaults to the directory containing
+	// this config file.
+	WrenchDir string `toml:"WrenchDir,omitempty"`
+
+	// All options below here are only used in "wrench" mode.
+
 	// (optional) Discord bot token. See README.md for details on how to create this.
 	//
 	// Disabled if an empty string.
+	//
+	// Only used in "wrench" mode.
 	DiscordBotToken string `toml:"DiscordBotToken,omitempty"`
 
 	// (required if DiscordBotToken is set) Discord guild/server ID to operate in.
 	//
 	// Find this via User Settings -> Advanced -> Enabled developer mode, then right-click on any
 	// server and Copy ID)
+	//
+	// Only used in "wrench" mode.
 	DiscordGuildID string `toml:"DiscordGuildID,omitempty"`
 
 	// (optional) Discord channel name for Wrench to send messages in. Defaults to "wrench"
+	//
+	// Only used in "wrench" mode.
 	DiscordChannel string `toml:"DiscordChannel,omitempty"`
 
 	// (optional) Discord channel name for Wrench to relay all Discord messages to. Defaults to "disabled"
+	//
+	// Only used in "wrench" mode.
 	ActivityChannel string `toml:"ActivityChannel,omitempty"`
 
-	// (optional) Directory for caching LetsEncrypt certificates
-	LetsEncryptCacheDir string `toml:"LetsEncryptCacheDir,omitempty"`
-
-	// (optional) Email to use for LetsEncrypt notifications
-	LetsEncryptEmail string `toml:"LetsEncryptEmail,omitempty"`
-
 	// (optional) When specified, this is an arbitrary secret of your choosing which can be used to
 	// send GitHub webhook events from the github.com/hexops/wrench repository itself to Wrench. It
 	// will respond to these by recompiling and launching itself:
 	//
 	// The webhook URL should be: /webhook/github/self
 	//
+	// Only used in "wrench" mode.
 	GitHubWebHookSecret string `toml:"GitHubWebHookSecret,omitempty"`
 
 	// (optional) When specified Wrench can send PRs and assist with GitHub.
 	//
 	// Only applicable if running as the Wrench server.
+	//
+	// Only used in "wrench" mode.
 	GitHubAccessToken string `toml:"GitHubAccessToken,omitempty"`
 
 	// (optional) When specified wrench runners can push to Git using this configuration.
 	// It is suggested to use a limited push access token for the password since it will
 	// be distributed to all runners.
 	//
 	// Only applicable if running as the Wrench server.
+	//
+	// Only used in "wrench" mode.
 	GitPushUsername    string `toml:"GitPushUsername,omitempty"`
 	GitPushPassword    string `toml:"GitPushPassword,omitempty"`
 	GitConfigUserName  string `toml:"GitConfigUserName,omitempty"`
 	GitConfigUserEmail string `toml:"GitConfigUserEmail,omitempty"`
 
 	// (optional) Generic secret used to authenticate with this server. Any arbitrary string.
+	//
+	// Only used in "wrench" mode.
 	Secret string `toml:"Secret,omitempty"`
 
 	// (optional) Act as a runner, connecting to the root Wrench server specified in ExternalURL.
+	//
+	// Only used in "wrench" mode.
 	Runner string `toml:"Runner,omitempty"`
+}
 
-	// Where Wrench should store its data, cofiguration, etc. Defaults to the directory containing
-	// this config file.
-	WrenchDir string `toml:"WrenchDir,omitempty"`
+func (c *Config) ModeType() ModeType {
+	if c.Mode != "" {
+		return ModeType(c.Mode)
+	}
+	if c.PkgProxy {
+		return ModePkg
+	}
+	return ModeWrench
 }
 
 func (c *Config) LogFilePath() string {

internal/wrench/http.go

@@ -46,11 +46,17 @@ func (b *Bot) httpStart() error {
 	}
 
 	var mux http.Handler
-	if b.Config.PkgProxy {
-		b.logf("http: PkgProxy mode enabled")
+	if b.Config.ModeType() == ModePkg {
+		b.logf("http: pkg mirror mode enabled")
 		mux = b.httpMuxPkgProxy(handler)
-	} else {
+	} else if b.Config.ModeType() == ModeZig {
+		b.logf("http: zig mirror mode enabled")
+		mux = b.httpMuxPkgProxy(handler)
+	} else if b.Config.ModeType() == ModeWrench {
+		b.logf("http: wrench mode enabled")
 		mux = b.httpMuxDefault(handler)
+	} else {
+		b.logf("invalid config mode=%q", b.Config.ModeType())
 	}
 
 	b.logf("http: listening on %v - %v", b.Config.Address, b.Config.ExternalURL)