Use system properties in Jacoco agent configuration

org.jacoco.agent.rt.test/src/org/jacoco/agent/rt/internal/ConfigLoaderTest.java

@@ -48,10 +48,68 @@ public void testSystemProperties() {
 		system.setProperty("output", "tcpserver"); // no prefix
 		system.setProperty("jacoco-agent.sessionid", "testid");
 		Properties config = ConfigLoader.load(
-				"/org/jacoco/agent/rt/agent-test.properties", system);
+				"/org/jacoco/agent/rt/internal/agent-test.properties", system);
 
 		assertEquals("mbean", config.get("output"));
 		assertEquals("testid", config.get("sessionid"));
 	}
 
-}
+	@Test
+	public void testEnvironmentVariableReplacement() {
+		Properties system = new Properties();
+		system.setProperty("user.home", "/user/home");
+		system.setProperty("java.version", "1.2.3");
+
+		Properties config = ConfigLoader.load(
+				"/org/jacoco/agent/rt/internal/agent-env-test.properties",
+				system);
+
+		assertEquals("/user/home/coverage/unit-test-agent-1.2.3.exec",
+				config.get("destfile"));
+	}
+
+	@Test
+	public void testSystemPropertiesEscpaingDollarCharacter() {
+		Properties system = new Properties();
+		system.setProperty("user.home", "/user/gerrit");
+		system.setProperty("jacoco-agent.replaceproperties", "true");
+
+		setSystemPropAndAssertEquals(system, "\\\\${ my test \\{ \\}",
+				"\\\\${ my test \\{ \\}");
+		setSystemPropAndAssertEquals(system, "${mytest", "${mytest");
+		setSystemPropAndAssertEquals(system, "$${user.home}", "$/user/gerrit");
+		setSystemPropAndAssertEquals(system, "\\${user.home}", "\\/user/gerrit");
+		setSystemPropAndAssertEquals(system, "${user.home}/test/path",
+				"/user/gerrit/test/path");
+	}
+
+	@Test
+	public void testSystemPropertiesNoPropertiesReplacement() {
+		Properties system = new Properties();
+		system.setProperty("user.home", "/user/gerrit");
+		system.setProperty("jacoco-agent.replaceproperties", "false");
+
+		setSystemPropAndAssertEquals(system, "$${user.home}", "$${user.home}");
+		setSystemPropAndAssertEquals(system, "\\${user.home}", "\\${user.home}");
+		setSystemPropAndAssertEquals(system, "${user.home}/test/path",
+				"${user.home}/test/path");
+	}
+
+	/**
+	 * @param systemPropertyValue
+	 *            Sets <code>system</code>'s &quot;jacoco-agent.destfile&quot;
+	 *            in <code>system</code> properties
+	 * @param expectedValue
+	 *            <code>expectedValue</code> returned by
+	 *            {@link ConfigLoader#load(String, Properties)} for key
+	 *            &quot;destfile&quot;
+	 */
+	private void setSystemPropAndAssertEquals(Properties system,
+			String systemPropertyValue, String expectedValue) {
+		system.setProperty("jacoco-agent.destfile", systemPropertyValue);
+		Properties config = ConfigLoader.load(
+				"/org/jacoco/agent/rt/internal/agent-env-test.properties",
+				system);
+		assertEquals(expectedValue, config.get("destfile"));
+	}
+}

org.jacoco.agent.rt.test/src/org/jacoco/agent/rt/internal/agent-env-test.properties

@@ -0,0 +1,2 @@
+destfile=${user.home}/coverage/unit-test-agent-${java.version}.exec
+replaceproperties=true

org.jacoco.agent.rt/src/org/jacoco/agent/rt/internal/ConfigLoader.java

@@ -15,6 +15,8 @@
 import java.io.InputStream;
 import java.util.Map;
 import java.util.Properties;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * Internal utility to load runtime configuration from a classpath resource and
@@ -48,6 +50,37 @@ static Properties load(final String resource, final Properties system) {
 			}
 		}
 
+		// 3. Perform environment variable replacement
+		if (Boolean.parseBoolean(result.getProperty("replaceproperties",
+				"false"))) {
+			final Pattern replacementPattern = Pattern
+					.compile("\\$\\{([A-Za-z_0-9.-]+)\\}");
+			for (final Map.Entry<Object, Object> entry : result.entrySet()) {
+				final String value = (String) entry.getValue();
+				final Matcher m = replacementPattern.matcher(value);
+				if (m.find()) {
+					final StringBuffer sb = new StringBuffer(value.length() * 2);
+					int offset = 0;
+					do {
+						final String propertyName = m.group(1);
+						if (propertyName != null) {
+							sb.append(value, offset, m.start());
+							// replace match by system property
+							sb.append(system.getProperty(propertyName, ""));
+						} else {
+							// keep original string
+							sb.append(value, offset, m.end());
+						}
+						offset = m.end();
+					} while (m.find());
+					if (offset < value.length()) {
+						sb.append(value, offset, value.length());
+					}
+					entry.setValue(sb.toString());
+				}
+			}
+		}
+
 		return result;
 	}
 

org.jacoco.build/pom.xml

@@ -515,7 +515,7 @@
             </goals>
             <configuration>
               <target>
-                <fileset dir="${basedir}" includes="**/*.java,**/*.xml,**/*.bsh" excludes="target/**,.idea/**,nb-configuration.xml" id="missinglicense.fileset">
+                <fileset dir="${basedir}" includes="**/*.java,**/*.xml,**/*.bsh" excludes="bin/**,target/**,.idea/**,nb-configuration.xml" id="missinglicense.fileset">
                   <not>
                     <and>
                       <contains text="Copyright (c) 2009, 2014 Mountainminds GmbH &amp; Co. KG and Contributors"/>

org.jacoco.doc/docroot/doc/agent.html

@@ -73,7 +73,7 @@ <h1>Java Agent</h1>
   <tbody>
     <tr>
       <td><code>destfile</code></td>
-      <td>Path to the output file for execution data.</td>
+      <td>Path to the output file for execution data. See also <code>replaceproperties</code> enabling system property replacement.</td>
       <td><code>jacoco.exec</code></td>
     </tr>
     <tr>
@@ -145,7 +145,9 @@ <h1>Java Agent</h1>
       <td>Output method to use for writing coverage data. Valid options are:
         <ul>
           <li><code>file</code>: At VM termination execution data is written to
-              the file specified in the <code>destfile</code> attribute.</li>
+              the file specified in the <code>destfile</code> attribute. See
+              also <code>replaceproperties</code> enabling system property
+              replacement.</li>
           <li><code>tcpserver</code>: The agent listens for incoming connections
               on the TCP port specified by the <code>address</code> and
               <code>port</code> attribute. Execution data is written to this
@@ -197,6 +199,16 @@ <h1>Java Agent</h1>
       </td>
       <td><code>false</code></td>
     </tr>
+    <tr>
+      <td><code>replaceproperties</code></td>
+      <td>If set to <code>true</code> the agent replaces 
+          <code>${system-property-name}</code> occurrences by the value of Java 
+          system property with key &quot;system-property-name&quot;. If the
+          property does not exist an empty string is used. Introduced in version 0.7.3.
+          Also see section about replacing system properties below.
+      </td>
+      <td><code>false</code></td>
+    </tr>
   </tbody>
 </table>
 
@@ -211,6 +223,30 @@ <h2>Security Consideration for Remote Agent Control</h2>
   application might be revealed or DOS attacks are possible. 
 </p>
 
+<h2>Replacing system properties in Agent configuration</h2>
+
+<p>
+  Example file <code>jacoco-agent.properties</code> for the agent's
+  <code>destfile</code>:
+
+   <pre><code>
+    replaceproperties=true
+    destfile=${user.home}/coverage-data/coverage.exec
+   </code></pre>
+
+   By default the replacement feature is disabled. The first line in the
+   example above enables it. Once enabled replacement is applied to all
+   Jacoco agent properties. Java's system properties can be used to override
+   the compile time configuration by adding
+   <code>-Djacoco-agent.replacementproperties=true</code> or
+   <code>-Djacoco-agent.destfile=${java.io.tempdir}/coverage.exec</code>
+   to Java's command line.<br/>
+   A regular expression <code>\$\{[A-Za-z_0-9.-]+\}</code> is used to
+   recognize and replace all occurrences. No escaping mechanism has been
+   implemented because backslash &quot;\&quot; is a path separator on Windows
+   and dollar &quot;$&quot; occurs in filenames of anonymous or inner classes.
+</p>
+
 </div>
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