From 3903b63d70d56bfe2590526cc83934f1b4737d71 Mon Sep 17 00:00:00 2001
From: Lucas Lara <lucaslorentzlara@hotmail.com>
Date: Thu, 12 Mar 2026 07:30:14 +0100
Subject: [PATCH] Support escaping dots in label keys with \.

The dot character is used as a nesting separator in Docker label keys,
making it impossible to use literal dots in directive names (e.g.
domain names like mydomain.fr or Caddy's {blocks.name} syntax).

This adds support for \. as an escaped literal dot, so:
  caddy.dynamic_dns.domains.mydomain\.fr
produces:
  dynamic_dns { domains { mydomain.fr } }

Fixes #767
Fixes #699

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 caddyfile/fromlabels.go                    |  7 ++++++-
 caddyfile/testdata/labels/escaped_dots.txt | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 caddyfile/testdata/labels/escaped_dots.txt

diff --git a/caddyfile/fromlabels.go b/caddyfile/fromlabels.go
index 61e7b98e..82d96396 100644
--- a/caddyfile/fromlabels.go
+++ b/caddyfile/fromlabels.go
@@ -5,12 +5,15 @@ import (
 	"math"
 	"regexp"
 	"strconv"
+	"strings"
 	"text/template"
 )
 
 var whitespaceRegex = regexp.MustCompile("\\s+")
 var labelParserRegex = regexp.MustCompile(`^(?:(.+)\.)?(?:(\d+)_)?([^.]+?)(?:_(\d+))?$`)
 
+const escapedDotPlaceholder = "\x00"
+
 // FromLabels converts key value labels into a caddyfile
 func FromLabels(labels map[string]string, templateData interface{}, templateFuncs template.FuncMap) (*Container, error) {
 	container := CreateContainer()
@@ -37,7 +40,9 @@ func getOrCreateBlock(container *Container, path string, blocksByPath map[string
 		return block
 	}
 
-	parentPath, order, name := parsePath(path)
+	parentPath, order, name := parsePath(strings.ReplaceAll(path, `\.`, escapedDotPlaceholder))
+	parentPath = strings.ReplaceAll(parentPath, escapedDotPlaceholder, `\.`)
+	name = strings.ReplaceAll(name, escapedDotPlaceholder, ".")
 
 	block := CreateBlock()
 	block.Order = order
diff --git a/caddyfile/testdata/labels/escaped_dots.txt b/caddyfile/testdata/labels/escaped_dots.txt
new file mode 100644
index 00000000..90a8d802
--- /dev/null
+++ b/caddyfile/testdata/labels/escaped_dots.txt
@@ -0,0 +1,22 @@
+caddy = (extendable-proxy)
+caddy.reverse_proxy.{blocks\.proxy_target} =
+caddy.reverse_proxy.{blocks\.proxy_options} =
+
+caddy_1 = localhost
+caddy_1.dynamic_dns.provider = cloudflare token123
+caddy_1.dynamic_dns.domains.mydomain\.fr =
+----------
+(extendable-proxy) {
+	reverse_proxy {
+		{blocks.proxy_options}
+		{blocks.proxy_target}
+	}
+}
+localhost {
+	dynamic_dns {
+		domains {
+			mydomain.fr
+		}
+		provider cloudflare token123
+	}
+}