Donavan Fritz
ff3ec65719
Synthetic CoreDNS Plugin CI/CD Build / test (push) Has been cancelled
Dockerfile used golang:1.21 but go.mod requires 1.25; CI was broken. Refactored plugin code with proper godoc comments, extracted helpers to eliminate duplicated response-building logic, modernized tests with t.Run subtests and shared assertion helpers, and rewrote README with configuration reference table and professional structure. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
104 lines
2.5 KiB
Go
104 lines
2.5 KiB
Go
package synthetic
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import (
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"fmt"
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"net"
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"strconv"
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"strings"
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"github.com/coredns/caddy"
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/plugin"
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)
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// syntheticConfig holds the parsed Corefile configuration for the synthetic plugin.
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type syntheticConfig struct {
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// net is the set of IP networks for which synthetic forward responses are
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// generated. Only addresses falling within these CIDRs will be resolved.
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net []*net.IPNet
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// forward is the DNS zone appended to synthetic hostnames when generating
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// PTR records (e.g., "example.com").
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forward string
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// ttl is the time-to-live value applied to all synthetic responses.
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// Defaults to 0 (no caching).
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ttl uint32
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// prefix is the hostname label prefix used to identify synthetic queries
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// (e.g., "ip-"). A trailing dash is appended automatically if absent.
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prefix string
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}
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func init() { plugin.Register("synthetic", setup) }
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// setup parses the Corefile configuration block for the synthetic plugin and
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// registers it in the CoreDNS handler chain.
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func setup(c *caddy.Controller) error {
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config, err := parseConfig(c)
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if err != nil {
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return err
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}
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dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
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return synthetic{Next: next, Config: config}
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})
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return nil
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}
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// parseConfig reads the synthetic { ... } block from the Corefile and returns
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// a validated syntheticConfig.
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func parseConfig(c *caddy.Controller) (syntheticConfig, error) {
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var config syntheticConfig
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for c.Next() {
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for c.NextBlock() {
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switch v := c.Val(); v {
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case "net":
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for _, arg := range c.RemainingArgs() {
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_, cidr, err := net.ParseCIDR(arg)
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if err != nil {
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return config, fmt.Errorf("synthetic: invalid CIDR notation: %v", arg)
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}
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config.net = append(config.net, cidr)
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}
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case "forward":
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args := c.RemainingArgs()
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if len(args) > 0 {
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config.forward = args[0]
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}
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case "ttl":
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for _, arg := range c.RemainingArgs() {
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ttl64, err := strconv.ParseUint(arg, 10, 32)
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if err != nil {
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return config, fmt.Errorf("synthetic: invalid ttl value: %v", arg)
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}
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config.ttl = uint32(ttl64)
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}
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case "prefix":
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args := c.RemainingArgs()
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if len(args) > 0 {
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config.prefix = args[0]
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}
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default:
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return config, c.Errf("unknown property '%s'", v)
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}
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}
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}
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// Apply defaults.
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if config.prefix == "" {
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config.prefix = "ip"
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}
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if !strings.HasSuffix(config.prefix, "-") {
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config.prefix += "-"
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}
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return config, nil
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}
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