Allow TC_INITSCRIPT to support absolute/relative path via file: URI

docs/modules/databases/index.md

@@ -64,14 +64,20 @@ Insert `tc:` after `jdbc:` as follows. Note that the hostname, port and database
 
 `jdbc:tc:postgis:9.6://hostname/databasename`
 
-## Using an init script
+## Using a classpath init script
 
 Testcontainers can run an initscript after the database container is started, but before your code is given a connection to it. The script must be on the classpath, and is referenced as follows:
 
 `jdbc:tc:mysql:5.7.22://hostname/databasename?TC_INITSCRIPT=somepath/init_mysql.sql`
 
 This is useful if you have a fixed script for setting up database schema, etc.
 
+## Using an init script from a file
+
+If the init script path is prefixed `file:`, it will be loaded from a file (relative to the working directory, which will usually be the project root).
+
+`jdbc:tc:mysql:5.7.22://hostname/databasename?TC_INITSCRIPT=file:src/main/resources/init_mysql.sql`
+
 #### Using an init function
 
 Instead of running a fixed script for DB setup, it may be useful to call a Java function that you define. This is intended to allow you to trigger database schema migration tools. To do this, add TC_INITFUNCTION to the URL as follows, passing a full path to the class name and method:

modules/jdbc-test/sql/init_mysql.sql

@@ -0,0 +1,5 @@
+CREATE TABLE bar (
+  foo VARCHAR(255)
+);
+
+INSERT INTO bar (foo) VALUES ('hello world');

modules/jdbc-test/src/test/java/org/testcontainers/jdbc/JDBCDriverTest.java

@@ -46,6 +46,7 @@ public static Iterable<Object[]> data() {
                 {"jdbc:tc:mysql://hostname/databasename?user=someuser&TC_INITSCRIPT=somepath/init_mysql.sql", EnumSet.of(Options.ScriptedSchema, Options.JDBCParams)},
                 {"jdbc:tc:mysql:5.5.43://hostname/databasename?user=someuser&TC_INITFUNCTION=org.testcontainers.jdbc.JDBCDriverTest::sampleInitFunction", EnumSet.of(Options.ScriptedSchema, Options.JDBCParams)},
                 {"jdbc:tc:mysql:5.5.43://hostname/databasename?user=someuser&password=somepwd&TC_INITSCRIPT=somepath/init_mysql.sql", EnumSet.of(Options.ScriptedSchema, Options.JDBCParams)},
+                {"jdbc:tc:mysql:5.5.43://hostname/databasename?user=someuser&password=somepwd&TC_INITSCRIPT=file:sql/init_mysql.sql", EnumSet.of(Options.ScriptedSchema, Options.JDBCParams)},
                 {"jdbc:tc:mysql:5.5.43://hostname/databasename?user=someuser&password=somepwd&TC_INITFUNCTION=org.testcontainers.jdbc.JDBCDriverTest::sampleInitFunction", EnumSet.of(Options.ScriptedSchema, Options.JDBCParams)},
                 {"jdbc:tc:mysql:5.5.43://hostname/databasename?TC_INITSCRIPT=somepath/init_unicode_mysql.sql&useUnicode=yes&characterEncoding=utf8", EnumSet.of(Options.CharacterSet)},
                 {"jdbc:tc:mysql:5.5.43://hostname/databasename", EnumSet.noneOf(Options.class)},

modules/jdbc/src/main/java/org/testcontainers/jdbc/ContainerDatabaseDriver.java

@@ -41,6 +41,7 @@ public class ContainerDatabaseDriver implements Driver {
     private static final Map<String, Set<Connection>> containerConnections = new HashMap<>();
     private static final Map<String, JdbcDatabaseContainer> jdbcUrlContainerCache = new HashMap<>();
     private static final Set<String> initializedContainers = new HashSet<>();
+    private static final String FILE_PATH_PREFIX = "file:";
 
     static {
         load();
@@ -177,8 +178,14 @@ private void runInitScriptIfRequired(final ConnectionUrl connectionUrl, Database
         if (connectionUrl.getInitScriptPath().isPresent()) {
             String initScriptPath = connectionUrl.getInitScriptPath().get();
             try {
-                URL resource = Thread.currentThread().getContextClassLoader().getResource(initScriptPath);
-
+                URL resource;
+                if (initScriptPath.startsWith(FILE_PATH_PREFIX)) {
+                    //relative workdir path
+                    resource = new URL(initScriptPath);
+                } else {
+                    //classpath resource
+                    resource = Thread.currentThread().getContextClassLoader().getResource(initScriptPath);
+                }
                 if (resource == null) {
                     LOGGER.warn("Could not load classpath init script: {}", initScriptPath);
                     throw new SQLException("Could not load classpath init script: " + initScriptPath + ". Resource not found.");