Rename the settings whose names do not say what they control (closes #234)

Applies the setting renames of the naming audit under the SWW_WAF_ and
SWW_RPROXY_ prefixes, with sneak's names for the IP reputation cache
time and the two time limits, which now take milliseconds. The rproxy
log field default_disposition becomes waf_backend_no_answer, and
config.Config and config.FromEnvironment become config.WAF and
config.WAFFromEnvironment. Go fields, test names and prose follow. No
aliases; nothing reads the old names.

Model: opus-5-5

internal/config/rproxy.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
-	"math"
 	"net/netip"
 	"net/url"
 	"strconv"
@@ -25,13 +24,15 @@ type RProxy struct {
 	TrustedProxies []netip.Prefix
 	// WAFBackend is waf's URL (SWW_RPROXY_WAF_BACKEND).
 	WAFBackend *url.URL
-	// Timeout is how long rproxy waits for waf's answer to a question,
-	// and to a report (SWW_RPROXY_TIMEOUT_MS). It cannot be off.
-	Timeout time.Duration
-	// DefaultDisposition is what is done with a request when waf cannot be
-	// connected to, does not answer at all, or does not answer within Timeout:
-	// allow or deny (SWW_RPROXY_DEFAULT_DISPOSITION).
-	DefaultDisposition string
+	// WAFBackendTimeout is how long rproxy waits for waf's answer to a
+	// question, and to a report (SWW_RPROXY_WAF_BACKEND_TIMEOUT_MS). It
+	// cannot be off.
+	WAFBackendTimeout time.Duration
+	// WAFBackendNoAnswerDisposition is what is done with a request when waf
+	// cannot be connected to, does not answer at all, or does not answer
+	// within WAFBackendTimeout: allow or deny
+	// (SWW_RPROXY_WAF_BACKEND_NO_ANSWER_DISPOSITION).
+	WAFBackendNoAnswerDisposition string
 	// MaxRequestSize is the largest request body (SWW_RPROXY_MAX_REQUEST_SIZE), and
 	// MaxResponseSize the largest response body (SWW_RPROXY_MAX_RESPONSE_SIZE).
 	MaxRequestSize  int64
@@ -62,9 +63,7 @@ var (
 			"such as http://127.0.0.1:8081")
 	errNeedsWAFBackend = errors.New(
 		"is required: it is waf's URL, such as http://waf:8080")
-	errNotDisposition  = errors.New("is not allow or deny")
-	errNotMilliseconds = errors.New(
-		"is not a whole number of milliseconds above zero, such as 2000")
+	errNotDisposition       = errors.New("is not allow or deny")
 	errNotMillisecondsOrOff = errors.New(
 		"is not a whole number of milliseconds above zero, such as 60000, or off",
 	)
@@ -89,9 +88,12 @@ func RProxyFromEnvironment(v *viper.Viper) (*RProxy, error) {
 			privateRanges,
 		),
 		WAFBackend: env.wafBackend("SWW_RPROXY_WAF_BACKEND"),
-		Timeout:    env.milliseconds("SWW_RPROXY_TIMEOUT_MS", "2000"),
-		DefaultDisposition: env.disposition(
-			"SWW_RPROXY_DEFAULT_DISPOSITION",
+		WAFBackendTimeout: env.milliseconds(
+			"SWW_RPROXY_WAF_BACKEND_TIMEOUT_MS",
+			"2000",
+		),
+		WAFBackendNoAnswerDisposition: env.disposition(
+			"SWW_RPROXY_WAF_BACKEND_NO_ANSWER_DISPOSITION",
 			"allow",
 		),
 		MaxRequestSize:  env.size("SWW_RPROXY_MAX_REQUEST_SIZE", "100M"),
@@ -173,19 +175,6 @@ func (e *environment) disposition(name, defaultValue string) string {
 	return value
 }
 
-// milliseconds reads a setting that is a whole number of milliseconds above
-// zero.
-func (e *environment) milliseconds(name, defaultValue string) time.Duration {
-	value := e.value(name, defaultValue)
-
-	duration, valid := parseMilliseconds(value)
-	if !valid {
-		e.check(name, fmt.Errorf("%q %w", value, errNotMilliseconds))
-	}
-
-	return duration
-}
-
 // millisecondsOrOff reads a setting that is a whole number of milliseconds
 // above zero, or off, which is 0.
 func (e *environment) millisecondsOrOff(
@@ -204,17 +193,6 @@ func (e *environment) millisecondsOrOff(
 	return duration
 }
 
-// parseMilliseconds reads a whole number of milliseconds above zero, and
-// reports whether it is one.
-func parseMilliseconds(value string) (time.Duration, bool) {
-	n, err := strconv.ParseInt(value, 10, 64)
-	if err != nil || n <= 0 || n > math.MaxInt64/int64(time.Millisecond) {
-		return 0, false
-	}
-
-	return time.Duration(n) * time.Millisecond, true
-}
-
 // parseUpstreamURL reads the app's URL: http or https, a host and an
 // optional port from 1 to 65535, and nothing else, since the request's
 // own path and query go to the app unchanged.