Require region codes are globally unique

This is required for the ENX redirector, but we've also always made the
assumption that these need to be globally unique.

Note that this requires changing the column to citext (for
case-insensitive matching) and to NULL out the default of '', since ''
is a duplicate of ''.

It also handles any existing duplicates by appending -N to them before
applying the database-level unique constraint.

cmd/server/assets/realmadmin/_form_general.html

@@ -22,11 +22,12 @@
     <small class="form-text text-muted">
       The realm name is displayed on the realm selection page and in the header
       when selected. Choose a descriptive name that your team will recognize.
+      This value must be globally unique in the system.
     </small>
   </div>
 
   <div class="form-label-group">
-    <input type="text" name="region_code" id="region-code" class="form-control{{if $realm.ErrorsFor "regionCode"}} is-invalid{{end}}"
+    <input type="text" name="region_code" id="region-code" class="form-control text-uppercase{{if $realm.ErrorsFor "regionCode"}} is-invalid{{end}}"
       value="{{$realm.RegionCode}}" placeholder="Region code" />
     <label for="region-code">Region code</label>
     {{if $realm.ErrorsFor "regionCode"}}
@@ -41,6 +42,7 @@
       <a href="https://en.wikipedia.org/wiki/List_of_ISO_3166_country_codes">ISO
       3166-1 country codes and ISO 3166-2 subdivision codes</a> where
       applicable. For example, Washington state would be <code>US-WA</code>.
+      This value must globally unique in the system.
     </small>
   </div>
 

pkg/controller/realmadmin/settings.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/google/exposure-notifications-verification-server/pkg/controller"
@@ -109,13 +110,13 @@ func (c *Controller) HandleSettings() http.Handler {
 		}
 
 		// General
-		if v := form.Name; v != "" {
+		if v := strings.TrimSpace(form.Name); v != "" {
 			realm.Name = v
 		}
-		if v := form.RegionCode; v != "" {
-			realm.RegionCode = v
+		if v := strings.TrimSpace(form.RegionCode); v != "" {
+			realm.RegionCode = strings.ToUpper(v)
 		}
-		if v := form.WelcomeMessage; v != "" {
+		if v := strings.TrimSpace(form.WelcomeMessage); v != "" {
 			realm.WelcomeMessage = v
 		}
 
@@ -138,7 +139,7 @@ func (c *Controller) HandleSettings() http.Handler {
 		if v := form.LongCodeDurationHours; v > 0 {
 			realm.LongCodeDuration.Duration = time.Duration(v) * time.Minute
 		}
-		if v := form.SMSTextTemplate; v != "" {
+		if v := strings.TrimSpace(form.SMSTextTemplate); v != "" {
 			realm.SMSTextTemplate = v
 		}
 

pkg/database/migrations.go

@@ -1131,6 +1131,84 @@ func (db *Database) getMigrations(ctx context.Context) *gormigrate.Gormigrate {
 				return nil
 			},
 		},
+		{
+			ID: "00049-MakeRegionCodeUnique",
+			Migrate: func(tx *gorm.DB) error {
+				// Make any existing empty string region codes to NULL. Without this,
+				// the new unique constraint will fail.
+				if err := tx.Exec("UPDATE realms SET region_code = NULL WHERE TRIM(region_code) = ''").Error; err != nil {
+					return err
+				}
+
+				// Make all region codes uppercase.
+				if err := tx.Exec("UPDATE realms SET region_code = UPPER(region_code) WHERE region_code IS NOT NULL").Error; err != nil {
+					return err
+				}
+
+				// Find any existing duplicate region codes - this could be combined
+				// into a much large SQL statement with the next thing, but I'm
+				// optimizing for readability here.
+				var dupRegionCodes []string
+				if err := tx.Model(&Realm{}).
+					Unscoped().
+					Select("UPPER(region_code) AS region_code").
+					Where("region_code IS NOT NULL").
+					Group("region_code").
+					Having("COUNT(*) > 1").
+					Pluck("region_code", &dupRegionCodes).
+					Error; err != nil {
+					return err
+				}
+
+				// Update any duplicate regions to not be duplicate anymore.
+				for _, dupRegionCode := range dupRegionCodes {
+					logger.Warn("de-duplicating region code %q", dupRegionCode)
+
+					// I call this the "Microsoft method". For each duplicate realm,
+					// append -N, starting with 1. If there are 3 realms with the region
+					// code "PA", their new values will be "PA", "PA-1", and "PA-2"
+					// respectively.
+					sql := `
+						UPDATE
+							realms
+						SET region_code = CONCAT(realms.region_code, '-', (z-1)::text)
+						FROM (
+							SELECT
+								id,
+								region_code,
+								ROW_NUMBER() OVER (ORDER BY id ASC) AS z
+							FROM realms
+							WHERE UPPER(region_code) = UPPER($1)
+						) AS sq
+						WHERE realms.id = sq.id AND sq.z > 1`
+					if err := tx.Exec(sql, dupRegionCode).Error; err != nil {
+						return err
+					}
+				}
+
+				sqls := []string{
+					// There's already a runtime constraint and validation on names, this
+					// is just an extra layer of protection at the database layer.
+					"ALTER TABLE realms ALTER COLUMN name SET NOT NULL",
+
+					// Make region code case insensitive and unique.
+					"ALTER TABLE realms ALTER COLUMN region_code TYPE CITEXT",
+					"ALTER TABLE realms ALTER COLUMN region_code DROP DEFAULT",
+					"ALTER TABLE realms ALTER COLUMN region_code DROP NOT NULL",
+					"ALTER TABLE realms ADD CONSTRAINT uix_realms_region_code UNIQUE (region_code)",
+				}
+
+				for _, sql := range sqls {
+					if err := tx.Exec(sql).Error; err != nil {
+						return err
+					}
+				}
+				return nil
+			},
+			Rollback: func(tx *gorm.DB) error {
+				return nil
+			},
+		},
 	})
 }