Initial implementation of Caddy module (#84)

* only supports pmtiles in top level of bucket, mounted at the root route
* does not have any custom credentials logic

caddy/pmtiles_proxy.go

@@ -0,0 +1,109 @@
+package pmtiles_proxy
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"strconv"
+
+	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
+	"github.com/protomaps/go-pmtiles/pmtiles"
+	"go.uber.org/zap"
+	"time"
+)
+
+func init() {
+	caddy.RegisterModule(Middleware{})
+	httpcaddyfile.RegisterHandlerDirective("pmtiles_proxy", parseCaddyfile)
+}
+
+type Middleware struct {
+	Bucket    string `json:"bucket"`
+	CacheSize int    `json:"cache_size"`
+	logger    *zap.Logger
+	server    *pmtiles.Server
+}
+
+func (Middleware) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		ID:  "http.handlers.pmtiles_proxy",
+		New: func() caddy.Module { return new(Middleware) },
+	}
+}
+
+func (m *Middleware) Provision(ctx caddy.Context) error {
+	m.logger = ctx.Logger()
+	logger := log.New(io.Discard, "", log.Ldate)
+	prefix := "." // serve only the root of the bucket for now, at the root route of Caddyfile
+	server, err := pmtiles.NewServer(m.Bucket, prefix, logger, 64, "", "https://example.com")
+	if err != nil {
+		return err
+	}
+	m.server = server
+	server.Start()
+	return nil
+}
+
+func (m *Middleware) Validate() error {
+	if m.Bucket == "" {
+		return fmt.Errorf("no bucket")
+	}
+	if m.CacheSize <= 0 {
+		m.CacheSize = 64
+	}
+	return nil
+}
+
+func (m Middleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
+	start := time.Now()
+	status_code, headers, body := m.server.Get(r.Context(), r.URL.Path)
+	for k, v := range headers {
+		w.Header().Set(k, v)
+	}
+	w.WriteHeader(status_code)
+	w.Write(body)
+	m.logger.Info("response", zap.Int("status", status_code), zap.String("path", r.URL.Path), zap.Duration("duration", time.Since(start)))
+
+	return next.ServeHTTP(w, r)
+}
+
+func (m *Middleware) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
+	for d.Next() {
+		for nesting := d.Nesting(); d.NextBlock(nesting); {
+			switch d.Val() {
+			case "bucket":
+				if !d.Args(&m.Bucket) {
+					return d.ArgErr()
+				}
+			case "cache_size":
+				var cacheSize string
+				if !d.Args(&cacheSize) {
+					return d.ArgErr()
+				}
+				num, err := strconv.Atoi(cacheSize)
+				if err != nil {
+					return d.ArgErr()
+				}
+				m.CacheSize = num
+			}
+		}
+	}
+	return nil
+}
+
+func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
+	var m Middleware
+	err := m.UnmarshalCaddyfile(h.Dispenser)
+	return m, err
+}
+
+var (
+	_ caddy.Provisioner           = (*Middleware)(nil)
+	_ caddy.Validator             = (*Middleware)(nil)
+	_ caddyhttp.MiddlewareHandler = (*Middleware)(nil)
+	_ caddyfile.Unmarshaler       = (*Middleware)(nil)
+)