Move to yaml-based configuration

This commit updates the configuration to be yaml-based and updates the
configuration to read in a yaml file.

internal/config/http.go

@@ -0,0 +1,94 @@
+package config
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/tkw1536/goprogram/lib/collection"
+)
+
+type HTTPConfig struct {
+	// Each created Drupal Instance corresponds to a single domain name.
+	// These domain names should either be a complete domain name or a sub-domain of a default domain.
+	// This setting configures the default domain-name to create subdomains of.
+	PrimaryDomain string `yaml:"domain" default:"localhost.kwarc.info" validate:"domain"`
+
+	// By default, only the 'self' domain above is caught.
+	// To catch additional domains, add them here (comma seperated)
+	ExtraDomains []string `yaml:"domains" validate:"domains"`
+
+	// The system can support setting up certificate(s) automatically.
+	// It can be enabled by setting an email for certbot certificates.
+	// This email address can be configured here.
+	CertbotEmail string `yaml:"certbot_email" validate:"email"`
+}
+
+// HTTPSEnabled returns if the distillery has HTTPS enabled, and false otherwise.
+func (hcfg HTTPConfig) HTTPSEnabled() bool {
+	return hcfg.CertbotEmail != ""
+}
+
+// HTTPSEnabledEnv returns "true" if https is enabled, and "false" otherwise.
+func (hcfg HTTPConfig) HTTPSEnabledEnv() string {
+	if hcfg.HTTPSEnabled() {
+		return "true"
+	}
+	return "false"
+}
+
+// HostFromSlug returns the hostname belonging to a given slug.
+// When the slug is empty, returns the default (top-level) domain.
+func (cfg HTTPConfig) HostFromSlug(slug string) string {
+	if slug == "" {
+		return cfg.PrimaryDomain
+	}
+	return fmt.Sprintf("%s.%s", slug, cfg.PrimaryDomain)
+}
+
+// SlugFromHost returns the slug belonging to the appropriate host.'
+//
+// When host is a top-level domain, returns "", true.
+// When no slug is found, returns "", false.
+func (cfg HTTPConfig) SlugFromHost(host string) (slug string, ok bool) {
+	// extract an ':port' that happens to be in the host.
+	domain, _, _ := strings.Cut(host, ":")
+	domain = TrimSuffixFold(domain, ".wisski") // remove optional ".wisski" ending that is used inside docker
+
+	domainL := strings.ToLower(domain)
+
+	// check all the possible domain endings
+	for _, suffix := range append([]string{cfg.PrimaryDomain}, cfg.ExtraDomains...) {
+		suffixL := strings.ToLower(suffix)
+		if domainL == suffixL {
+			return "", true
+		}
+		if strings.HasSuffix(domainL, "."+suffixL) {
+			return domain[:len(domain)-len(suffix)-1], true
+		}
+	}
+
+	// no domain found!
+	return "", ok
+}
+
+func TrimSuffixFold(s string, suffix string) string {
+	if len(s) >= len(suffix) && strings.EqualFold(s[len(s)-len(suffix):], suffix) {
+		return s[:len(s)-len(suffix)]
+	}
+	return s
+}
+
+// HostRule returns a traefik rule for the given names
+// TODO: Move this over!
+func HostRule(names ...string) string {
+	quoted := collection.MapSlice(names, func(name string) string {
+		return "`" + name + "`"
+	})
+	return fmt.Sprintf("Host(%s)", strings.Join(quoted, ","))
+}
+
+// DefaultHostRule returns the default traefik hostname rule for this distillery.
+// This consists of the [DefaultDomain] as well as [ExtraDomains].
+func (cfg HTTPConfig) DefaultHostRule() string {
+	return HostRule(append([]string{cfg.PrimaryDomain}, cfg.ExtraDomains...)...)
+}