cli: warn the user if the time zone database is unavailable

Release note (cli change): CockroachDB will now print out an error
message and an informative hint if the time zone database is unusable.

pkg/cli/demo.go

@@ -173,6 +173,8 @@ func runDemo(cmd *cobra.Command, gen workload.Generator) error {
 `, adminURL)
 	}
 
+	checkTzDatabaseAvailability(context.Background())
+
 	conn := makeSQLConn(connURL)
 	defer conn.Close()
 

pkg/cli/start.go

@@ -491,6 +491,11 @@ func runStart(cmd *cobra.Command, args []string) error {
 	// registered.
 	reportConfiguration(ctx)
 
+	// Until/unless CockroachDB embeds its own tz database, we want
+	// an early sanity check. It's better to inform the user early
+	// than to get surprising errors during SQL queries.
+	checkTzDatabaseAvailability(ctx)
+
 	// ReadyFn will be called when the server has started listening on
 	// its network sockets, but perhaps before it has done bootstrapping
 	// and thus before Start() completes.
@@ -916,6 +921,15 @@ func clientFlags() string {
 	return strings.Join(flags, " ")
 }
 
+func checkTzDatabaseAvailability(ctx context.Context) {
+	if _, err := timeutil.LoadLocation("America/New_York"); err != nil {
+		log.Shout(ctx, log.Severity_ERROR,
+			"unable to load named time zones, time zone support will be degraded.\n"+
+				"Hint: check that the time zone database is installed on your system, or\n"+
+				"set the ZONEINFO environment variable to a Go time zone .zip archive.")
+	}
+}
+
 func reportConfiguration(ctx context.Context) {
 	serverCfg.Report(ctx)
 	if envVarsUsed := envutil.GetEnvVarsUsed(); len(envVarsUsed) > 0 {