Merge pull request #96 from zonkyio/configurable-database-connections

#93 Make max_connections property configurable for all providers

Author: tomix26

embedded-database-spring-test/src/main/java/io/zonky/test/db/provider/impl/OpenTablePostgresDatabaseProvider.java

@@ -32,6 +32,7 @@
 import org.apache.commons.lang3.RandomStringUtils;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.core.env.Environment;
+import org.springframework.jdbc.core.JdbcTemplate;
 
 import javax.sql.DataSource;
 import java.io.IOException;
@@ -51,8 +52,6 @@
 
 public class OpenTablePostgresDatabaseProvider implements DatabaseProvider {
 
-    private static final int MAX_DATABASE_CONNECTIONS = 300;
-
     private static final LoadingCache<DatabaseConfig, DatabaseInstance> databases = CacheBuilder.newBuilder()
             .build(new CacheLoader<DatabaseConfig, DatabaseInstance>() {
                 public DatabaseInstance load(DatabaseConfig config) throws IOException {
@@ -122,7 +121,12 @@ private DatabaseInstance(DatabaseConfig config) throws IOException {
             config.applyTo(builder);
 
             postgres = builder.start();
-            semaphore = new Semaphore(MAX_DATABASE_CONNECTIONS);
+
+            DataSource dataSource = postgres.getDatabase("postgres", "postgres");
+            JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
+            Integer maxConnections = jdbcTemplate.queryForObject("show max_connections", Integer.class);
+
+            semaphore = new Semaphore(maxConnections);
         }
 
         public DatabaseTemplate getTemplate(ClientConfig config, DatabasePreparer preparer) {
@@ -204,11 +208,11 @@ private DatabaseConfig(Map<String, String> initdbProperties, Map<String, String>
         }
 
         public final void applyTo(EmbeddedPostgres.Builder builder) {
+            builder.setServerConfig("max_connections", "300");
             builder.setPGStartupWait(Duration.ofSeconds(20L));
             initdbProperties.forEach(builder::setLocaleConfig);
             configProperties.forEach(builder::setServerConfig);
             customizers.forEach(c -> c.accept(builder));
-            builder.setServerConfig("max_connections", String.valueOf(MAX_DATABASE_CONNECTIONS));
         }
 
         @Override

embedded-database-spring-test/src/main/java/io/zonky/test/db/provider/impl/ZonkyPostgresDatabaseProvider.java

@@ -32,6 +32,7 @@
 import org.apache.commons.lang3.RandomStringUtils;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.core.env.Environment;
+import org.springframework.jdbc.core.JdbcTemplate;
 
 import javax.sql.DataSource;
 import java.io.IOException;
@@ -51,8 +52,6 @@
 
 public class ZonkyPostgresDatabaseProvider implements DatabaseProvider {
 
-    private static final int MAX_DATABASE_CONNECTIONS = 300;
-
     private static final LoadingCache<ClusterKey, DatabaseInstance> databases = CacheBuilder.newBuilder()
             .build(new CacheLoader<ClusterKey, DatabaseInstance>() {
                 public DatabaseInstance load(ClusterKey key) throws IOException {
@@ -126,7 +125,12 @@ private DatabaseInstance(DatabaseConfig config) throws IOException {
             config.applyTo(builder);
 
             postgres = builder.start();
-            semaphore = new Semaphore(MAX_DATABASE_CONNECTIONS);
+
+            DataSource dataSource = postgres.getDatabase("postgres", "postgres");
+            JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
+            Integer maxConnections = jdbcTemplate.queryForObject("show max_connections", Integer.class);
+
+            semaphore = new Semaphore(maxConnections);
         }
 
         public DatabaseTemplate getTemplate(ClientConfig config, DatabasePreparer preparer) {
@@ -210,11 +214,11 @@ private DatabaseConfig(Map<String, String> initdbProperties, Map<String, String>
         }
 
         public final void applyTo(EmbeddedPostgres.Builder builder) {
+            builder.setServerConfig("max_connections", "300");
             builder.setPGStartupWait(Duration.ofSeconds(20L));
             initdbProperties.forEach(builder::setLocaleConfig);
             configProperties.forEach(builder::setServerConfig);
             customizers.forEach(c -> c.accept(builder));
-            builder.setServerConfig("max_connections", String.valueOf(MAX_DATABASE_CONNECTIONS));
         }
 
         @Override

embedded-database-spring-test/src/test/java/io/zonky/test/db/config/ConfigurationPropertiesIntegrationTest.java

@@ -54,7 +54,7 @@ public void testConfigurationProperties() throws Exception {
         assertThat(collate).isEqualTo("cs_CZ.UTF-8");
 
         String maxConnections = jdbcTemplate.queryForObject("show max_connections", String.class);
-        assertThat(maxConnections).isEqualTo("300"); // this is a default value that can not be changed
+        assertThat(maxConnections).isEqualTo("100");
 
         String sharedBuffers = jdbcTemplate.queryForObject("show shared_buffers", String.class);
         assertThat(sharedBuffers).isEqualTo("64MB");

embedded-database-spring-test/src/test/java/io/zonky/test/db/provider/impl/OpenTablePostgresDatabaseProviderTest.java

@@ -136,7 +136,7 @@ public void testConfigurationProperties() throws SQLException {
         assertThat(collate).isEqualTo("cs_CZ.UTF-8");
 
         String maxConnections = jdbcTemplate.queryForObject("show max_connections", String.class);
-        assertThat(maxConnections).isEqualTo("300");
+        assertThat(maxConnections).isEqualTo("100");
 
         String sharedBuffers = jdbcTemplate.queryForObject("show shared_buffers", String.class);
         assertThat(sharedBuffers).isEqualTo("64MB");

embedded-database-spring-test/src/test/java/io/zonky/test/db/provider/impl/ZonkyPostgresDatabaseProviderTest.java

@@ -162,7 +162,7 @@ public void testConfigurationProperties() throws SQLException {
         assertThat(collate).isEqualTo("cs_CZ.UTF-8");
 
         String maxConnections = jdbcTemplate.queryForObject("show max_connections", String.class);
-        assertThat(maxConnections).isEqualTo("300");
+        assertThat(maxConnections).isEqualTo("100");
 
         String sharedBuffers = jdbcTemplate.queryForObject("show shared_buffers", String.class);
         assertThat(sharedBuffers).isEqualTo("64MB");