feat: Change renew rc when cert is still valid

Sometimes the lego Client may fail to contact the CA due to some
temporary networking issue on the host. The certificate may otherwise
still be valid, and a user may want to ignore this issue.

This change modifies the renew service so that if the lego client
is nil, but the certificate is not expired, the exit code of the
program will be 2 instead of 1.

In order to implement this, I had to change the setup function to remove
a usage of log.Fatalf which in turn required me to introduce explicit
os.Exit calls in some commands. Although this was the lowest patch delta
solution, I also considered refactoring the setup entirely to remove
log.Fatalf, and return setup errors instead.

cmd/cmd_renew.go

@@ -124,7 +124,9 @@ func createRenew() *cli.Command {
 
 func renew(ctx *cli.Context) error {
 	account, client := setup(ctx, NewAccountsStorage(ctx))
-	setupChallenges(ctx, client)
+	if client != nil {
+		setupChallenges(ctx, client)
+	}
 
 	if account.Registration == nil {
 		log.Fatalf("Account %s is not registered. Use 'run' to register a new account.\n", account.Email)
@@ -162,7 +164,7 @@ func renewForDomains(ctx *cli.Context, client *lego.Client, certsStorage *Certif
 	var ariRenewalTime *time.Time
 	var replacesCertID string
 
-	if !ctx.Bool(flgARIDisable) {
+	if !ctx.Bool(flgARIDisable) && client != nil {
 		ariRenewalTime = getARIRenewalTime(ctx, cert, domain, client)
 		if ariRenewalTime != nil {
 			now := time.Now().UTC()
@@ -186,9 +188,23 @@ func renewForDomains(ctx *cli.Context, client *lego.Client, certsStorage *Certif
 
 	if ariRenewalTime == nil && !needRenewal(cert, domain, ctx.Int(flgDays)) &&
 		(!forceDomains || slices.Equal(certDomains, domains)) {
+		// Warn the user that renewal check occurred offline, but the cert is not expired yet.
+		if client == nil {
+			log.Warnf(
+				"[%s] Failed to check ARI as there is no client."+
+					" Check previous error messages for possible initialization issues.",
+				domain,
+			)
+			os.Exit(2)
+		}
 		return nil
 	}
 
+	if client == nil {
+		// Abort renewal if we don't have a lego client
+		os.Exit(1)
+	}
+
 	// This is just meant to be informal for the user.
 	timeLeft := cert.NotAfter.Sub(time.Now().UTC())
 	log.Infof("[%s] acme: Trying renewal with %d hours remaining", domain, int(timeLeft.Hours()))
@@ -274,7 +290,7 @@ func renewForCSR(ctx *cli.Context, client *lego.Client, certsStorage *Certificat
 	var ariRenewalTime *time.Time
 	var replacesCertID string
 
-	if !ctx.Bool(flgARIDisable) {
+	if !ctx.Bool(flgARIDisable) && client != nil {
 		ariRenewalTime = getARIRenewalTime(ctx, cert, domain, client)
 		if ariRenewalTime != nil {
 			now := time.Now().UTC()
@@ -293,9 +309,23 @@ func renewForCSR(ctx *cli.Context, client *lego.Client, certsStorage *Certificat
 	}
 
 	if ariRenewalTime == nil && !needRenewal(cert, domain, ctx.Int(flgDays)) {
+		// Warn the user that renewal check occurred offline, but the cert is not expired yet.
+		if client == nil {
+			log.Warnf(
+				"[%s] Failed to check ARI as there is no client."+
+					" Check previous error messages for an indicator of initialization issues.",
+				domain,
+			)
+			os.Exit(2)
+		}
 		return nil
 	}
 
+	if client == nil {
+		// Abort renewal if we don't have a lego client
+		os.Exit(1)
+	}
+
 	// This is just meant to be informal for the user.
 	timeLeft := cert.NotAfter.Sub(time.Now().UTC())
 	log.Infof("[%s] acme: Trying renewal with %d hours remaining", domain, int(timeLeft.Hours()))

cmd/cmd_revoke.go

@@ -1,6 +1,8 @@
 package cmd
 
 import (
+	"os"
+
 	"github.com/go-acme/lego/v4/acme"
 	"github.com/go-acme/lego/v4/log"
 	"github.com/urfave/cli/v2"
@@ -39,6 +41,9 @@ func createRevoke() *cli.Command {
 
 func revoke(ctx *cli.Context) error {
 	acc, client := setup(ctx, NewAccountsStorage(ctx))
+	if client == nil {
+		os.Exit(1)
+	}
 
 	if acc.Registration == nil {
 		log.Fatalf("Account %s is not registered. Use 'run' to register a new account.\n", acc.Email)

cmd/cmd_run.go

@@ -94,6 +94,9 @@ func run(ctx *cli.Context) error {
 	accountsStorage := NewAccountsStorage(ctx)
 
 	account, client := setup(ctx, accountsStorage)
+	if client == nil {
+		os.Exit(1)
+	}
 	setupChallenges(ctx, client)
 
 	if account.Registration == nil {

cmd/setup.go

@@ -58,7 +58,8 @@ func newClient(ctx *cli.Context, acc registration.User, keyType certcrypto.KeyTy
 
 	client, err := lego.NewClient(config)
 	if err != nil {
-		log.Fatalf("Could not create client: %v", err)
+		log.Warnf("Could not create client: %v", err)
+		return nil
 	}
 
 	if client.GetExternalAccountRequired() && !ctx.IsSet(flgEAB) {