feat(config): accept templates for PROXIED and TTL (#214)

* feat(config): PROXIED and TTL accept templates

* docs: document Go templates

* test: improve coverage

* test: improve coverage

.golangci.yaml

@@ -24,6 +24,7 @@ linters:
     - ifshort # deprecated
     - interfacer # deprecated
     - ireturn # ireturn works poorly for the style with private types and public interfaces
+    - maintidx # It seems the linter never leads to code changes
     - maligned # deprecated, and I value readability over bytes saved by alignment
     - nlreturn # I don't agree with the style enforced by nlreturn
     - nonamedreturns # named returns are needed in the internal updator package

README.markdown

@@ -345,12 +345,26 @@ In most cases, `CF_ACCOUNT_ID` is not needed.
 | `PROXIED` | Boolean values, such as `true`, `false`, `0` and `1`. See [strconv.ParseBool](https://pkg.go.dev/strconv#ParseBool) | Whether new DNS records should be proxied by Cloudflare | No | `false`
 | `TTL` | Time-to-live (TTL) values in seconds | The TTL values used to create new DNS records | No | `1` (This means “automatic” to Cloudflare)
 
-🧪 Experimental features: (Please [share your case at this GitHub issue](https://github.com/favonia/cloudflare-ddns/issues/199) so that we can further revise the design. Thanks!)
+> <details>
+> <summary>🧪 Experimental support of Go templates:</summary>
+>
+> Both `PROXIED` and `TTL` can be [Go templates](https://pkg.go.dev/text/template) for per-domain settings. For example, `PROXIED={{not (suffix "example.org")}}` means all domains should be proxied except domains like `www.example.org` and `example.org`. The Go templates are executed with the following two custom functions:
+> - `domain(patterns ...string) bool`
+>
+>   Returns `true` if and only if the target domain matches one of `patterns`. All domains are normalized before comparison; for example, internationalized domain names are converted to Punycode before comparing them.
+> - `suffix(patterns ...string) bool`
+>
+>   Returns `true` if and only if the target domain has one of `patterns` as itself or its parent (or ancestor). Note that labels in domains must fully match; for example, the suffix `b.org` will not match `www.bb.org` because `bb.org` and `b.org` are incomparable, while the suffix `bb.org` will match `www.bb.org`.
+>
+> Some examples:
+> - `TTL={{if suffix "b.c"}} 60 {{else if domain "d.e.f" "a.bb.c" }} 90 {{else}} 120 {{end}}`
+>
+>   For the domain `b.c` and its descendants, the TTL is 60, and for the domains `d.e.f` and `a.bb.c`, the TTL is 90, and then for all other domains, the TTL is 120.
+> - `PROXIED={{and (suffix "b.c") (not (domain "a.b.c"))}}`
+>
+>   Proxy the domain `b.c` and its descendants except for the domain `a.b.c`.
+> </details>
 
-| Name | Valid Values | Meaning | Required? | Default Value |
-| ---- | ------------ | ------- | --------- | ------------- |
-| `PROXIED_DOMAINS` | Comma-separated fully qualified domain names or wildcard domain names | The domains for which the new DNS records should be proxied by Cloudflare, overriding the global setting (`PROXIED`) for these domains | No | `""` (empty)
-| `NON_PROXIED_DOMAINS` | Comma-separated fully qualified domain names or wildcard domain names | The domains for which the new DNS records should **not** be proxied by Cloudflare, overriding the global setting (`PROXIED`) for these domains | No | `""` (empty)
 </details>
 
 <details>
@@ -412,7 +426,7 @@ If you are using Kubernetes, run `kubectl replace -f cloudflare-ddns.yaml` after
 | `cloudflare.authentication.api_key` | ❌ | _Use the newer, more secure [API tokens](https://dash.cloudflare.com/profile/api-tokens)_ |
 | `cloudflare.zone_id` | ✔️ | Not needed; automatically retrieved from the server |
 | `cloudflare.subdomains[].name` | ✔️ | Use `DOMAINS` with **fully qualified domain names** (FQDNs); for example, if your zone is `example.org` and your subdomain is `www`, use `DOMAINS=sub.example.org` |
-| `cloudflare.subdomains[].proxied` | ✔️ | Use `PROXIED=true` or `PROXIED=false` to specify the global proxy setting, and then use `PROXIED_DOMAINS` and `NON_PROXIED_DOMAINS` with **fully qualified domain names** (FQDNs) to override the global setting if desired |
+| `cloudflare.subdomains[].proxied` | ✔️ | Use the experimental support of Go templates in `PROXIED` to specify per-domain settings; see above for the detailed documentation |
 | `a` | ✔️ | Both IPv4 and IPv6 are enabled by default; use `IP4_PROVIDER=none` to disable IPv4 |
 | `aaaa` | ✔️ | Both IPv4 and IPv6 are enabled by default; use `IP6_PROVIDER=none` to disable IPv6 |
 | `proxied` | ✔️ | Use `PROXIED=true` or `PROXIED=false` |

cmd/ddns.go

@@ -68,7 +68,7 @@ func initConfig(ctx context.Context, ppfmt pp.PP) (*config.Config, api.Handle, s
 	}
 
 	// Get the setter
-	s, ok := setter.New(ppfmt, h, c.TTL)
+	s, ok := setter.New(ppfmt, h)
 	if !ok {
 		bye()
 	}

internal/api/ttl.go

@@ -1,11 +1,14 @@
 package api
 
 import (
+	"sort"
 	"strconv"
 )
 
 type TTL int
 
+const TTLAuto = 1
+
 func (t TTL) Int() int {
 	return int(t)
 }
@@ -15,8 +18,12 @@ func (t TTL) String() string {
 }
 
 func (t TTL) Describe() string {
-	if t == 1 {
-		return "1 (automatic)"
+	if t == TTLAuto {
+		return "1 (auto)"
 	}
 	return strconv.Itoa(t.Int())
 }
+
+func SortTTLs(s []TTL) {
+	sort.Slice(s, func(i, j int) bool { return int(s[i]) < int(s[j]) })
+}

internal/api/ttl_test.go

@@ -15,7 +15,7 @@ func TestTTLDescribe(t *testing.T) {
 		seconds     int
 		description string
 	}{
-		"automatic": {1, "1 (automatic)"},
+		"automatic": {1, "1 (auto)"},
 		"2":         {2, "2"},
 		"30":        {30, "30"},
 		"293":       {293, "293"},