Polish "Add support for environment variables"

Closes gh-12800

spring-boot-project/spring-boot-docs/src/main/asciidoc/howto.adoc

@@ -2771,14 +2771,6 @@ See {spring-boot-maven-plugin-site}/examples/run-debug.html[this example] for mo
 details.
 
 
-[[howto-set-env-maven-run]]
-=== Run Spring Boot Application with Environment variables Started with Maven
-To set up the environment variables to a Spring Boot application that was started with Maven, you
-can use the `environmentVariables` property of the {spring-boot-maven-plugin-site}[maven plugin].
-
-See {spring-boot-maven-plugin-site}/examples/run-with-env.html[this example] for more
-details.
-
 
 [[howto-build-an-executable-archive-with-ant]]
 === Build an Executable Archive from Ant without Using `spring-boot-antlib`

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/RunProcess.java

@@ -69,12 +69,8 @@ public class RunProcess {
 		return run(waitForProcess, Arrays.asList(args), Collections.emptyMap());
 	}
 
-	public int run(boolean waitForProcess, String[] args, Map<String, String> environmentVariables) throws IOException {
-		return run(waitForProcess, Arrays.asList(args), environmentVariables);
-	}
-
-	protected int run(boolean waitForProcess, Collection<String> args, Map<String, String> environmentVariables)
-			throws IOException {
+	public int run(boolean waitForProcess, Collection<String> args,
+			Map<String, String> environmentVariables) throws IOException {
 		ProcessBuilder builder = new ProcessBuilder(this.command);
 		builder.directory(this.workingDirectory);
 		builder.command().addAll(args);

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/it/run-envargs/src/main/java/org/test/SampleApplication.java

@@ -18,7 +18,6 @@ package org.test;
 
 public class SampleApplication {
 
-
 	public static void main(String[] args) {
 		assertEnvValue("ENV1", "5000");
 		assertEnvValue("ENV2", "Some Text");
@@ -26,14 +25,13 @@ public class SampleApplication {
 		assertEnvValue("ENV4", "");
 
 		System.out.println("I haz been run");
-
 	}
 
-
-	static void assertEnvValue(String envKey, String expectedValue) {
+	private static void assertEnvValue(String envKey, String expectedValue) {
 		String actual = System.getenv(envKey);
 		if (!expectedValue.equals(actual)) {
-			throw new IllegalStateException("env property [" + envKey + "] mismatch (got [" + actual + "], expected [" + expectedValue + "]");
+			throw new IllegalStateException("env property [" + envKey + "] mismatch "
+					+ "(got [" + actual + "], expected [" + expectedValue + "]");
 		}
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractRunMojo.java

@@ -24,7 +24,6 @@ import java.net.URL;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -118,12 +117,12 @@ public abstract class AbstractRunMojo extends AbstractDependencyFilterMojo {
 	private Map<String, String> systemPropertyVariables;
 
 	/**
-	 * List of Environment variables that should be associated with the forked process used to run the
-	 * application.
-	 * <p>NOTE: the use of Environment variables means that processes will be started by forking a
-	 * new JVM.
+	 * List of Environment variables that should be associated with the forked process
+	 * used to run the application. NOTE: the use of Environment variables means that
+	 * processes will be started by forking a new JVM.
+	 * @since 2.1
 	 */
-	@Parameter(property = "spring-boot.run.environmentVariables")
+	@Parameter
 	private Map<String, String> environmentVariables;
 
 	/**
@@ -231,7 +230,6 @@ public abstract class AbstractRunMojo extends AbstractDependencyFilterMojo {
 		return (this.environmentVariables != null && !this.environmentVariables.isEmpty());
 	}
 
-
 	private boolean hasWorkingDirectorySet() {
 		return this.workingDirectory != null;
 	}
@@ -273,22 +271,19 @@ public abstract class AbstractRunMojo extends AbstractDependencyFilterMojo {
 	private void doRunWithForkedJvm(String startClassName)
 			throws MojoExecutionException, MojoFailureException {
 		List<String> args = new ArrayList<>();
-		Map<String, String> envVariables = new LinkedHashMap<>();
 		addAgents(args);
 		addJvmArgs(args);
 		addClasspath(args);
 		args.add(startClassName);
 		addArgs(args);
-		addEnvironmentVariables(envVariables);
-		runWithForkedJvm(this.workingDirectory, args, envVariables);
+		runWithForkedJvm(this.workingDirectory, args, determineEnvironmentVariables());
 	}
 
-
 	/**
 	 * Run with a forked VM, using the specified command line arguments.
 	 * @param workingDirectory the working directory of the forked JVM
 	 * @param args the arguments (JVM arguments and application arguments)
-	 * @param environmentVariables the environment variables;
+	 * @param environmentVariables the environment variables
 	 * @throws MojoExecutionException in case of MOJO execution errors
 	 * @throws MojoFailureException in case of MOJO failures
 	 */
@@ -316,27 +311,24 @@ public abstract class AbstractRunMojo extends AbstractDependencyFilterMojo {
 		return runArguments;
 	}
 
-
 	/**
 	 * Resolve the environment variables to use.
-	 *
 	 * @return a {@link EnvVariables} defining the environment variables
 	 */
 	protected EnvVariables resolveEnvVariables() {
 		return new EnvVariables(this.environmentVariables);
 	}
 
-
 	private void addArgs(List<String> args) {
 		RunArguments applicationArguments = resolveApplicationArguments();
 		Collections.addAll(args, applicationArguments.asArray());
 		logArguments("Application argument(s): ", this.arguments);
 	}
 
-	private void addEnvironmentVariables(Map<String, String> environmentVariables) {
+	private Map<String, String> determineEnvironmentVariables() {
 		EnvVariables envVariables = resolveEnvVariables();
-		environmentVariables.putAll(envVariables.asMap());
 		logArguments("Environment variable(s): ", envVariables.asArray());
+		return envVariables.asMap();
 	}
 
 	/**

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/EnvVariables.java

@@ -29,53 +29,39 @@ import java.util.Map;
  */
 class EnvVariables {
 
-	private static final String SPACE = "=";
-	private static final String NO_VALUE = "";
+	private final Map<String, String> variables;
 
-	private final Map<String, String> args = new LinkedHashMap<>();
-
-	EnvVariables(Map<String, String> args) {
-		this.args.putAll(getArgs(args));
-	}
-
-	Map<String, String> asMap() {
-		return Collections.unmodifiableMap(this.args);
-	}
-
-	String[] asArray() {
-		List<String> args = new ArrayList<>(this.args.size());
-		for (Map.Entry<String, String> arg : this.args.entrySet()) {
-			args.add(arg.getKey() + SPACE + arg.getValue());
-		}
-		return args.toArray(new String[args.size()]);
+	EnvVariables(Map<String, String> variables) {
+		this.variables = parseEnvVariables(variables);
 	}
 
-
-	private Map<String, String> getArgs(Map<String, String> args) {
-
+	private static Map<String, String> parseEnvVariables(Map<String, String> args) {
 		if (args == null || args.isEmpty()) {
 			return Collections.emptyMap();
 		}
-
 		Map<String, String> result = new LinkedHashMap<>();
 		for (Map.Entry<String, String> e : args.entrySet()) {
-			if (hasText(e.getKey())) {
+			if (e.getKey() != null) {
 				result.put(e.getKey(), getValue(e.getValue()));
 			}
 		}
 		return result;
 	}
 
-	private String getValue(String value) {
-		if (hasText(value)) {
-			return value;
-		}
-		return NO_VALUE;
+	private static String getValue(String value) {
+		return (value != null ? value : "");
 	}
 
-	private boolean hasText(String source) {
-		return source != null && !source.trim().isEmpty();
+	public Map<String, String> asMap() {
+		return Collections.unmodifiableMap(this.variables);
 	}
 
+	public String[] asArray() {
+		List<String> args = new ArrayList<>(this.variables.size());
+		for (Map.Entry<String, String> arg : this.variables.entrySet()) {
+			args.add(arg.getKey() + "=" + arg.getValue());
+		}
+		return args.toArray(new String[0]);
+	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RunMojo.java

@@ -66,14 +66,15 @@ public class RunMojo extends AbstractRunMojo {
 	}
 
 	@Override
-	protected void runWithForkedJvm(File workingDirectory, List<String> args, Map<String, String> environmentVariables)
+	protected void runWithForkedJvm(File workingDirectory, List<String> args,
+			Map<String, String> environmentVariables)
 			throws MojoExecutionException {
 		try {
 			RunProcess runProcess = new RunProcess(workingDirectory,
 					new JavaExecutable().toString());
 			Runtime.getRuntime()
 					.addShutdownHook(new Thread(new RunProcessKiller(runProcess)));
-			int exitCode = runProcess.run(true, args.toArray(new String[0]), environmentVariables);
+			int exitCode = runProcess.run(true, args, environmentVariables);
 			if (exitCode == 0 || exitCode == EXIT_CODE_SIGINT) {
 				return;
 			}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/StartMojo.java

@@ -47,7 +47,6 @@ import org.springframework.boot.loader.tools.RunProcess;
  * stopped after.
  *
  * @author Stephane Nicoll
- * @author Dmytro Nosan
  * @since 1.3.0
  * @see StopMojo
  */
@@ -90,7 +89,8 @@ public class StartMojo extends AbstractRunMojo {
 	private final Object lock = new Object();
 
 	@Override
-	protected void runWithForkedJvm(File workingDirectory, List<String> args, Map<String, String> environmentVariables)
+	protected void runWithForkedJvm(File workingDirectory, List<String> args,
+			Map<String, String> environmentVariables)
 			throws MojoExecutionException, MojoFailureException {
 		RunProcess runProcess = runProcess(workingDirectory, args, environmentVariables);
 		try {
@@ -102,12 +102,13 @@ public class StartMojo extends AbstractRunMojo {
 		}
 	}
 
-	private RunProcess runProcess(File workingDirectory, List<String> args, Map<String, String> environmentVariables)
+	private RunProcess runProcess(File workingDirectory, List<String> args,
+			Map<String, String> environmentVariables)
 			throws MojoExecutionException {
 		try {
 			RunProcess runProcess = new RunProcess(workingDirectory,
 					new JavaExecutable().toString());
-			runProcess.run(false, args.toArray(new String[0]), environmentVariables);
+			runProcess.run(false, args, environmentVariables);
 			return runProcess;
 		}
 		catch (Exception ex) {

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/apt/examples/run-with-env.apt.vm → spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/apt/examples/run-env-variables.apt.vm

  -----
- Specify environment variables
+ Using environment variables
  -----
 Dmytro Nosan
  -----
  2018-04-08
  -----
 
-  The environmnet variables to use for a particular application can be specified using the <<<environmentVariables>>>
-  argument. The following configuration enables the 'ENV1', 'ENV2', 'ENV3', 'ENV4' env variables:
+  Environment variables can be specified using the <<<environmentVariables>>> attribute.
+  The following sets the 'ENV1', 'ENV2', 'ENV3', 'ENV4' env variables:
 
 ---
 <project>
@@ -38,6 +38,13 @@ Dmytro Nosan
 </project>
 ---
 
-  Note that since you specified some Environment variables, the process is forked automatically.
+  If the value is empty or not defined (i.e. <<<<MY_ENV/>>>>), the env variable is set
+  with an empty String as the value.
+
+  Any String typed Maven variable can be passed as system properties. Any attempt to pass
+  any other Maven variable type (e.g. a <<<List>>> or a <<<URL>>> variable) will cause the
+  variable expression to be passed literally (unevaluated).
+
+  Environment variables defined this way take precedence over existing values.
 
 

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/apt/index.apt

@@ -54,14 +54,14 @@ Spring Boot Maven Plugin
 
   * {{{./examples/run-system-properties.html}Using system properties}}
 
+  * {{{./examples/run-env-variables.html}Using environment variables}}
+
   * {{{./examples/it-random-port.html}Random port for integration tests}}
 
   * {{{./examples/it-skip.html}Skip integration tests}}
 
   * {{{./examples/run-profiles.html}Specify active profiles}}
 
-  * {{{./examples/run-with-env.html}Specify Environment variables}}
-
   * {{{./examples/build-info.html}Generate build information}}
 
   * {{{./examples/custom-layout.html}Custom layout}}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/apt/usage.apt.vm

@@ -140,11 +140,12 @@ mvn spring-boot:run
 
   If you need to specify some JVM arguments (i.e. for debugging purposes), you can use
   the <<<jvmArguments>>> parameter, see {{{./examples/run-debug.html}Debug the application}}
-  for more details. There is also explicit support
-  {{{./examples/run-system-properties.html}for system properties}} and
-  {{{./examples/run-with-env.html}environment variables}}. As a convenience, the profiles
-  to enable are handled by a specific property (<<<profiles>>>), see
-  {{{./examples/run-profiles.html}Specify active profiles}}.
+  for more details. There is also explicit support for
+  {{{./examples/run-system-properties.html}system properties}} and
+  {{{./examples/run-env-variables.html}environment variables}}.
+
+  As a convenience, the profiles to enable are handled by a specific property (
+  <<<profiles>>>), see {{{./examples/run-profiles.html}Specify active profiles}}.
 
   Spring Boot 1.3 has introduced <<<devtools>>>, a module to improve the development-time
   experience when working on Spring Boot applications. To enable it, just add the following

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/site.xml

@@ -12,10 +12,10 @@
 			<item name="Exclude a dependency" href="examples/exclude-dependency.html"/>
 			<item name="Debug the application" href="examples/run-debug.html"/>
 			<item name="Using system properties" href="examples/run-system-properties.html"/>
+			<item name="Using environment variable" href="examples/run-env-variables.html"/>
 			<item name="Random port for integration tests" href="examples/it-random-port.html"/>
 			<item name="Skip integration tests" href="examples/it-skip.html"/>
 			<item name="Specify active profiles" href="examples/run-profiles.html"/>
-			<item name="Specify environment variables" href="examples/run-with-env.html"/>
 			<item name="Generate build information" href="examples/build-info.html"/>
 			<item name="Custom layout" href="examples/custom-layout.html"/>
 		</menu>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/EnvVariablesTests.java

@@ -22,6 +22,7 @@ import java.util.Map;
 import org.junit.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
 
 /**
  * Tests for {@link EnvVariables}.
@@ -33,40 +34,29 @@ public class EnvVariablesTests {
 	@Test
 	public void asNull() {
 		Map<String, String> args = new EnvVariables(null).asMap();
-		assertThat(args).hasSize(0);
+		assertThat(args).isEmpty();
 	}
 
-
 	@Test
 	public void asArray() {
 		assertThat(new EnvVariables(getTestArgs()).asArray())
-				.contains("key=My Value")
-				.contains("key1= tt ")
-				.contains("key2=")
-				.contains("key3=");
+				.contains("key=My Value", "key1= tt ", "key2=   ", "key3=");
 	}
 
 	@Test
 	public void asMap() {
-		assertThat(new EnvVariables(getTestArgs()).asMap())
-				.containsEntry("key", "My Value")
-				.containsEntry("key1", " tt ")
-				.containsEntry("key2", "")
-				.containsEntry("key3", "");
+		assertThat(new EnvVariables(getTestArgs()).asMap()).containsExactly(
+				entry("key", "My Value"), entry("key1", " tt "), entry("key2", "   "),
+				entry("key3", ""));
 	}
 
-
 	private Map<String, String> getTestArgs() {
 		Map<String, String> args = new LinkedHashMap<>();
 		args.put("key", "My Value");
-		//should not be trimmed
 		args.put("key1", " tt ");
 		args.put("key2", "   ");
 		args.put("key3", null);
 		return args;
 	}
 
-
-
-
 }