v2.0.47: HTTPS Everywhere — TLS-only control plane, agents/CLI/MCP

Breaking change release. Plaintext HTTP listener removed. The certctl
control plane now terminates TLS 1.3 on :8443 via
http.Server.ListenAndServeTLS. No CERTCTL_TLS_ENABLED=false escape
hatch. No dual-listener mode. One-step cutover per docs/upgrade-to-tls.md.

Server
- cmd/server/tls.go: certHolder with SIGHUP hot-reload + atomic cert
  swap, buildServerTLSConfig (TLS 1.3 min, GetCertificate callback),
  preflightServerTLS validation
- cmd/server/main.go: ListenAndServeTLS in place of ListenAndServe,
  watchSIGHUP wiring, cert/key path config threading
- tls_test.go: 418-line regression coverage of reload, preflight,
  callback behavior, SAN validation

Config
- CERTCTL_TLS_CERT_PATH / CERTCTL_TLS_KEY_PATH (required)
- Plaintext rejection: agents/CLI/MCP pre-flight-fail on http://
  URLs with a pointer to docs/upgrade-to-tls.md

Agents, CLI, MCP
- All three pre-flight-reject http:// URLs with fail-loud diagnostic
- CERTCTL_SERVER_CA_BUNDLE_PATH for private-CA trust
- CERTCTL_SERVER_TLS_INSECURE_SKIP_VERIFY for dev-only bypass
  (loud warning on startup)
- install-agent.sh emits both vars as commented template lines

docker-compose
- certctl-tls-init sidecar generates SAN-valid self-signed cert into
  deploy/test/certs/ on first boot
- All demo-stack curls pin against ca.crt with --cacert

Helm chart
- Three TLS provisioning modes, exactly one required:
  - server.tls.existingSecret (operator-supplied)
  - server.tls.certManager.enabled (cert-manager integration)
  - server.tls.selfSigned.enabled (eval only — not for production)
- server-certificate.yaml template for cert-manager mode
- helm install without a TLS source fails at template render with
  a pointer to docs/tls.md

CI
- .github/workflows/ci.yml Helm Chart Validation step renders the
  chart in both existingSecret and cert-manager modes, plus an
  inverse guard-regression test that asserts helm template MUST
  refuse to render when no TLS source is configured. Previously
  the single `helm template` invocation hit the certctl.tls.required
  fail-loud guard and exit-1'd CI. Four invocations now: lint
  (existingSecret), template (existingSecret), template
  (cert-manager), template (no args — must fail).

Integration tests
- deploy/test/integration_test.go stands up the Compose stack over
  HTTPS, extracts the CA bundle, and exercises every certctl API
  over https://localhost:8443
- All 34 integration subtests green (per Phase 8 local CI-parity)

Documentation
- New: docs/tls.md (provisioning patterns, rotation, SIGHUP reload)
- New: docs/upgrade-to-tls.md (one-step cutover, no-downgrade
  warnings, fleet-roll sequencing)
- CHANGELOG.md: v2.2.0 "HTTPS Everywhere — The Irony" entry
  (file heading unchanged; release tag is v2.0.47)
- All curls in docs/, examples/, deploy/helm/ guides use
  https://localhost:8443 --cacert

Verification
- grep -rn "ListenAndServe[^T]" cmd/ internal/ → 0 hits
- grep -rn "\"http://" cmd/ internal/ → 2 benign hits (Caddy admin
  API default, SSRF doc comment) — zero certctl endpoints
- Tasks #197–#206 (Phases 0–8) all closed in the tracker

Files: 65 changed, 3489 insertions, 372 deletions (pre-CI-fix).

cmd/mcp-server/main.go

@@ -4,8 +4,10 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"net/url"
 	"os"
 	"os/signal"
+	"strings"
 
 	gomcp "github.com/modelcontextprotocol/go-sdk/mcp"
 
@@ -16,14 +18,33 @@ import (
 var Version = "dev"
 
 func main() {
+	// HTTPS-Everywhere (v2.2): the server is HTTPS-only. The default URL
+	// uses https://; plaintext http:// is rejected by validateHTTPSScheme
+	// below with a fail-loud pre-flight diagnostic pointing at
+	// docs/upgrade-to-tls.md, so operators never get a TCP-refused or
+	// TLS-handshake-error downstream. See docs/tls.md for CA bundle and
+	// insecure-skip-verify guidance.
 	serverURL := os.Getenv("CERTCTL_SERVER_URL")
 	if serverURL == "" {
-		serverURL = "http://localhost:8443"
+		serverURL = "https://localhost:8443"
+	}
+
+	if err := validateHTTPSScheme(serverURL); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		fmt.Fprintf(os.Stderr, "\nThe certctl control plane is HTTPS-only as of v2.2.\n")
+		fmt.Fprintf(os.Stderr, "See docs/upgrade-to-tls.md for the cutover walkthrough.\n")
+		os.Exit(1)
 	}
 
 	apiKey := os.Getenv("CERTCTL_API_KEY")
+	caBundlePath := os.Getenv("CERTCTL_SERVER_CA_BUNDLE_PATH")
+	insecure := strings.EqualFold(os.Getenv("CERTCTL_SERVER_TLS_INSECURE_SKIP_VERIFY"), "true")
 
-	client := mcp.NewClient(serverURL, apiKey)
+	client, err := mcp.NewClient(serverURL, apiKey, caBundlePath, insecure)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
 
 	server := gomcp.NewServer(&gomcp.Implementation{
 		Name:    "certctl",
@@ -41,3 +62,26 @@ func main() {
 		log.Fatalf("MCP server error: %v", err)
 	}
 }
+
+// validateHTTPSScheme rejects plaintext and empty-scheme server URLs at
+// startup so operators get a fail-loud diagnostic before any network call,
+// not a TCP-refused or TLS-handshake-error downstream. See docs/upgrade-to-tls.md.
+func validateHTTPSScheme(serverURL string) error {
+	if serverURL == "" {
+		return fmt.Errorf("server URL is empty — set CERTCTL_SERVER_URL to an https:// URL (e.g., https://certctl-server:8443)")
+	}
+	u, err := url.Parse(serverURL)
+	if err != nil {
+		return fmt.Errorf("server URL %q is not a valid URL: %w", serverURL, err)
+	}
+	switch strings.ToLower(u.Scheme) {
+	case "https":
+		return nil
+	case "http":
+		return fmt.Errorf("server URL %q uses plaintext http:// — the certctl control plane is HTTPS-only", serverURL)
+	case "":
+		return fmt.Errorf("server URL %q is missing a scheme — expected https://", serverURL)
+	default:
+		return fmt.Errorf("server URL %q uses unsupported scheme %q — expected https://", serverURL, u.Scheme)
+	}
+}