Add a few warnings to the connection switcher

lib/active_record_shards/configuration_parser.rb

@@ -10,6 +10,11 @@ def explode(conf)
 
       conf.to_a.each do |env_name, env_config|
         next unless shards = env_config.delete('shards')
+
+        unless shards.keys.all? { |shard_name| shard_name.is_a?(Integer) }
+          raise "All shard names must be integers: #{shards.keys.inspect}."
+        end
+
         env_config['shard_names'] = shards.keys
         shards.each do |shard_name, shard_conf|
           expand_child!(env_config, shard_conf)

lib/active_record_shards/connection_switcher.rb

@@ -120,7 +120,7 @@ def connection_specification_name
       name = current_shard_selection.resolve_connection_name(sharded: is_sharded?, configurations: configurations)
 
       unless configurations[name] || name == "primary"
-        raise ActiveRecord::AdapterNotSpecified, "No database defined by #{name} in database.yml"
+        raise ActiveRecord::AdapterNotSpecified, "No database defined by #{name} in your database config. (configurations: #{configurations.inspect})"
       end
 
       name
@@ -144,7 +144,10 @@ def current_shard_id
 
     def shard_names
       unless config = configurations[shard_env]
-        raise "Did not find #{shard_env} in configurations, did you forget to add it to your database.yml ? (configurations: #{configurations.inspect})"
+        raise "Did not find #{shard_env} in configurations, did you forget to add it to your database config? (configurations: #{configurations.inspect})"
+      end
+      unless config.fetch(SHARD_NAMES_CONFIG_KEY, []).all? { |shard_name| shard_name.is_a?(Integer) }
+        raise "All shard names must be integers: #{config[SHARD_NAMES_CONFIG_KEY].inspect}."
       end
       config[SHARD_NAMES_CONFIG_KEY] || []
     end
@@ -158,6 +161,9 @@ def switch_connection(options)
         end
 
         if options.key?(:shard)
+          unless config = configurations[shard_env]
+            raise "Did not find #{shard_env} in configurations, did you forget to add it to your database config? (configurations: #{configurations.inspect})"
+          end
           current_shard_selection.shard = options[:shard]
         end
 

test/configuration_parser_test.rb

@@ -19,78 +19,78 @@
           "username"    => "root",
           "password"    => nil,
           "host"        => "main_slave_host",
-          "shard_names" => ["a", "b"].to_set
+          "shard_names" => [500, 501].to_set
         }, @conf)
       end
     end
 
     describe "shard a" do
       describe "master" do
-        before { @conf = @exploded_conf["test_shard_a"] }
+        before { @conf = @exploded_conf["test_shard_500"] }
         it "be exploded" do
           @conf["shard_names"] = @conf["shard_names"].to_set
           assert_equal({
             "adapter"     => "mysql",
             "encoding"    => "utf8",
-            "database"    => "ars_test_shard_a",
+            "database"    => "ars_test_shard_500",
             "port"        => 123,
             "username"    => "root",
             "password"    => nil,
-            "host"        => "shard_a_host",
-            "shard_names" => ["a", "b"].to_set
+            "host"        => "shard_500_host",
+            "shard_names" => [500, 501].to_set
           }, @conf)
         end
       end
 
       describe "slave" do
-        before { @conf = @exploded_conf["test_shard_a_slave"] }
+        before { @conf = @exploded_conf["test_shard_500_slave"] }
         it "be exploded" do
           @conf["shard_names"] = @conf["shard_names"].to_set
           assert_equal({
             "adapter"     => "mysql",
             "encoding"    => "utf8",
-            "database"    => "ars_test_shard_a",
+            "database"    => "ars_test_shard_500",
             "port"        => 123,
             "username"    => "root",
             "password"    => nil,
-            "host"        => "shard_a_slave_host",
-            "shard_names" => ["a", "b"].to_set
+            "host"        => "shard_500_slave_host",
+            "shard_names" => [500, 501].to_set
           }, @conf)
         end
       end
     end
 
     describe "shard b" do
       describe "master" do
-        before { @conf = @exploded_conf["test_shard_b"] }
+        before { @conf = @exploded_conf["test_shard_501"] }
         it "be exploded" do
           @conf["shard_names"] = @conf["shard_names"].to_set
           assert_equal({
             "adapter"     => "mysql",
             "encoding"    => "utf8",
-            "database"    => "ars_test_shard_b",
+            "database"    => "ars_test_shard_501",
             "port"        => 123,
             "username"    => "root",
             "password"    => nil,
-            "host"        => "shard_b_host",
-            "shard_names" => ["a", "b"].to_set
+            "host"        => "shard_501_host",
+            "shard_names" => [500, 501].to_set
           }, @conf)
         end
       end
 
       describe "slave" do
-        before { @conf = @exploded_conf["test_shard_b_slave"] }
+        before { @conf = @exploded_conf["test_shard_501_slave"] }
         it "be exploded" do
           @conf["shard_names"] = @conf["shard_names"].to_set
           assert_equal({
             "adapter"     => "mysql",
             "encoding"    => "utf8",
-            "database"    => "ars_test_shard_b_slave",
+            "database"    => "ars_test_shard_501_slave",
             "port"        => 123,
             "username"    => "root",
             "password"    => nil,
-            "host"        => "shard_b_host",
-            "shard_names" => ["a", "b"].to_set
+            "host"        => "shard_501_host",
+            "shard_names" => [500, 501].to_set
           }, @conf)
         end
       end

test/connection_switching_test.rb

@@ -75,8 +75,8 @@
         assert_includes(database_names, @shard_1_master.select_value("SELECT DATABASE()"))
 
         assert_equal(2, database_shards.size)
-        assert_includes(database_shards, "0")
-        assert_includes(database_shards, "1")
+        assert_includes(database_shards, 0)
+        assert_includes(database_shards, 1)
       end
 
       it "execute the block unsharded" do

test/database.yml

@@ -11,7 +11,7 @@ mysql: &MYSQL
 test:
   <<: *MYSQL
   database: ars_test
-  shard_names: ['0', '1']
+  shard_names: [0, 1]
 
 test_slave:
   <<: *MYSQL

test/database_parse_test.yml

@@ -9,13 +9,13 @@ test:
   slave:
     host: main_slave_host
   shards:
-    a:
-      database: ars_test_shard_a
-      host: shard_a_host
+    500:
+      database: ars_test_shard_500
+      host: shard_500_host
       slave:
-        host: shard_a_slave_host
-    b:
-      database: ars_test_shard_b
-      host: shard_b_host
+        host: shard_500_slave_host
+    501:
+      database: ars_test_shard_501
+      host: shard_501_host
       slave:
-        database: ars_test_shard_b_slave
+        database: ars_test_shard_501_slave

test/database_tasks.yml

@@ -10,7 +10,7 @@ test:
   slave:
     database: ars_tasks_test_slave
   shards:
-    a:
+    0:
       database: ars_tasks_test_shard_a
-    b:
+    1:
       database: ars_tasks_test_shard_b