fix: Optionally hide rendered environment variables (#798)

* new OriginType.ENV_VARIABLE
* deserialization of unknown originType ordinal, but this doesn't really
  help for compatibility if serialized with new version and deserialized
  with old version

build.sbt

@@ -95,7 +95,11 @@ lazy val configLib =  Project("config", file("config"))
       "CONFIG_FORCE_a__c" -> "3",
       "CONFIG_FORCE_a___c" -> "4",
       "CONFIG_FORCE_akka_version" -> "foo",
-      "CONFIG_FORCE_akka_event__handler__dispatcher_max__pool__size" -> "10")
+      "CONFIG_FORCE_akka_event__handler__dispatcher_max__pool__size" -> "10",
+      "SECRET_A" -> "A", // ConfigTest.renderShowEnvVariableValues
+      "SECRET_B" -> "B", // ConfigTest.renderShowEnvVariableValues
+      "SECRET_C" -> "C" // ConfigTest.renderShowEnvVariableValues
+    )
 
     OsgiKeys.exportPackage                 := Seq("com.typesafe.config", "com.typesafe.config.impl")
     publish                                := sys.error("use publishSigned instead of plain publish")

config/src/main/java/com/typesafe/config/ConfigRenderOptions.java

@@ -21,13 +21,15 @@ public final class ConfigRenderOptions {
     private final boolean comments;
     private final boolean formatted;
     private final boolean json;
+    private final boolean showEnvVariableValues;
 
     private ConfigRenderOptions(boolean originComments, boolean comments, boolean formatted,
-            boolean json) {
+            boolean json, boolean showEnvVariableValues) {
         this.originComments = originComments;
         this.comments = comments;
         this.formatted = formatted;
         this.json = json;
+        this.showEnvVariableValues = showEnvVariableValues;
     }
 
     /**
@@ -38,7 +40,7 @@ public final class ConfigRenderOptions {
      * @return the default render options
      */
     public static ConfigRenderOptions defaults() {
-        return new ConfigRenderOptions(true, true, true, true);
+        return new ConfigRenderOptions(true, true, true, true, true);
     }
 
     /**
@@ -48,7 +50,7 @@ public final class ConfigRenderOptions {
      * @return the concise render options
      */
     public static ConfigRenderOptions concise() {
-        return new ConfigRenderOptions(false, false, false, true);
+        return new ConfigRenderOptions(false, false, false, true, true);
     }
 
     /**
@@ -64,7 +66,7 @@ public final class ConfigRenderOptions {
         if (value == comments)
             return this;
         else
-            return new ConfigRenderOptions(originComments, value, formatted, json);
+            return new ConfigRenderOptions(originComments, value, formatted, json, showEnvVariableValues);
     }
 
     /**
@@ -97,7 +99,7 @@ public final class ConfigRenderOptions {
         if (value == originComments)
             return this;
         else
-            return new ConfigRenderOptions(value, comments, formatted, json);
+            return new ConfigRenderOptions(value, comments, formatted, json, showEnvVariableValues);
     }
 
     /**
@@ -122,7 +124,7 @@ public final class ConfigRenderOptions {
         if (value == formatted)
             return this;
         else
-            return new ConfigRenderOptions(originComments, comments, value, json);
+            return new ConfigRenderOptions(originComments, comments, value, json, showEnvVariableValues);
     }
 
     /**
@@ -150,7 +152,32 @@ public final class ConfigRenderOptions {
         if (value == json)
             return this;
         else
-            return new ConfigRenderOptions(originComments, comments, formatted, value);
+            return new ConfigRenderOptions(originComments, comments, formatted, value, showEnvVariableValues);
+    }
+
+    /**
+     * Returns options with showEnvVariableValues toggled. This controls if values set from
+     * environment variables are included in the rendered string.
+     *
+     * @param value
+     *            true to include environment variable values in the render
+     * @return options with requested setting for environment variables
+     */
+    public ConfigRenderOptions setShowEnvVariableValues(boolean value) {
+        if (value == showEnvVariableValues)
+            return this;
+        else
+            return new ConfigRenderOptions(originComments, comments, formatted, json, value);
+    }
+
+    /**
+     * Returns whether the options enable rendering of environment variable values. This method is mostly used
+     * by the config lib internally, not by applications.
+     *
+     * @return true if environment variable values should be rendered
+     */
+    public boolean getShowEnvVariableValues() {
+        return showEnvVariableValues;
     }
 
     /**
@@ -174,6 +201,8 @@ public final class ConfigRenderOptions {
             sb.append("formatted,");
         if (json)
             sb.append("json,");
+        if (showEnvVariableValues)
+            sb.append("showEnvVariableValues,");
         if (sb.charAt(sb.length() - 1) == ',')
             sb.setLength(sb.length() - 1);
         sb.append(")");

config/src/main/java/com/typesafe/config/impl/AbstractConfigValue.java

@@ -357,8 +357,20 @@ abstract class AbstractConfigValue implements ConfigValue, MergeableValue {
     }
 
     protected void render(StringBuilder sb, int indent, boolean atRoot, ConfigRenderOptions options) {
-        Object u = unwrapped();
+        if (hideEnvVariableValue(options)) {
-        sb.append(u.toString());
+            sb.append("<env variable>");
+        } else {
+            Object u = unwrapped();
+            sb.append(u.toString());
+        }
+    }
+
+    protected boolean hideEnvVariableValue(ConfigRenderOptions options) {
+        return !options.getShowEnvVariableValues() && origin.originType() == OriginType.ENV_VARIABLE;
+    }
+
+    protected void appendHiddenEnvVariableValue(StringBuilder sb) {
+        sb.append("\"<env variable>\"");
     }
 
     @Override

config/src/main/java/com/typesafe/config/impl/ConfigImpl.java

@@ -342,7 +342,7 @@ public class ConfigImpl {
     }
 
     private static AbstractConfigObject loadEnvVariables() {
-        return PropertiesParser.fromStringMap(newSimpleOrigin("env variables"), System.getenv());
+        return PropertiesParser.fromStringMap(newEnvVariable("env variables"), System.getenv());
     }
 
     private static class EnvVariablesHolder {
@@ -544,4 +544,8 @@ public class ConfigImpl {
     public static ConfigOrigin newURLOrigin(URL url) {
         return SimpleConfigOrigin.newURL(url);
     }
+
+    public static ConfigOrigin newEnvVariable(String description) {
+        return SimpleConfigOrigin.newEnvVariable(description);
+    }
 }

config/src/main/java/com/typesafe/config/impl/ConfigString.java

@@ -80,11 +80,15 @@ abstract class ConfigString extends AbstractConfigValue implements Serializable
 
     @Override
     protected void render(StringBuilder sb, int indent, boolean atRoot, ConfigRenderOptions options) {
-        String rendered;
+        if (hideEnvVariableValue(options)) {
-        if (options.getJson())
+            appendHiddenEnvVariableValue(sb);
-            rendered = ConfigImplUtil.renderJsonString(value);
+        } else {
-        else
+            String rendered;
-            rendered = ConfigImplUtil.renderStringUnquotedIfPossible(value);
+            if (options.getJson())
-        sb.append(rendered);
+                rendered = ConfigImplUtil.renderJsonString(value);
+            else
+                rendered = ConfigImplUtil.renderStringUnquotedIfPossible(value);
+            sb.append(rendered);
+        }
     }
 }

config/src/main/java/com/typesafe/config/impl/OriginType.java

@@ -5,5 +5,6 @@ enum OriginType {
     GENERIC,
     FILE,
     URL,
-    RESOURCE
+    RESOURCE,
+    ENV_VARIABLE
 }

config/src/main/java/com/typesafe/config/impl/SimpleConfigOrigin.java

@@ -77,6 +77,10 @@ final class SimpleConfigOrigin implements ConfigOrigin {
         return newResource(resource, null);
     }
 
+    static SimpleConfigOrigin newEnvVariable(String description) {
+        return new SimpleConfigOrigin(description, -1, -1, OriginType.ENV_VARIABLE, null, null, null);
+    }
+
     @Override
     public SimpleConfigOrigin withLineNumber(int lineNumber) {
         if (lineNumber == this.lineNumber && lineNumber == this.endLineNumber) {
@@ -139,6 +143,10 @@ final class SimpleConfigOrigin implements ConfigOrigin {
         }
     }
 
+    OriginType originType() {
+        return originType;
+    }
+
     @Override
     public boolean equals(Object other) {
         if (other instanceof SimpleConfigOrigin) {
@@ -484,7 +492,11 @@ final class SimpleConfigOrigin implements ConfigOrigin {
         Number originTypeOrdinal = (Number) m.get(SerializedField.ORIGIN_TYPE);
         if (originTypeOrdinal == null)
             throw new IOException("Missing ORIGIN_TYPE field");
-        OriginType originType = OriginType.values()[originTypeOrdinal.byteValue()];
+        OriginType originType;
+        if (originTypeOrdinal.byteValue() < OriginType.values().length)
+            originType = OriginType.values()[originTypeOrdinal.byteValue()];
+        else
+            originType = OriginType.GENERIC; // ENV_VARIABLE was added in a later version
         String urlOrNull = (String) m.get(SerializedField.ORIGIN_URL);
         String resourceOrNull = (String) m.get(SerializedField.ORIGIN_RESOURCE);
         @SuppressWarnings("unchecked")

config/src/test/resources/env-variables.conf

@@ -0,0 +1,4 @@
+secret = a
+secret = ${?SECRET_A}
+secrets = ["b", "c"]
+secrets = [${?SECRET_B}, ${?SECRET_C}]

config/src/test/scala/Rendering.scala

@@ -1,3 +1,5 @@
+package foo;
+
 import com.typesafe.config.ConfigFactory
 import com.typesafe.config.ConfigRenderOptions
 
@@ -6,11 +8,13 @@ object RenderExample extends App {
     val originComments = args.contains("--origin-comments")
     val comments = args.contains("--comments")
     val hocon = args.contains("--hocon")
+    val hideEnvVariableValues = args.contains("--hide-env-variable-values")
     val options = ConfigRenderOptions.defaults()
         .setFormatted(formatted)
         .setOriginComments(originComments)
         .setComments(comments)
         .setJson(!hocon)
+        .setShowEnvVariableValues(!hideEnvVariableValues)
 
     def render(what: String) {
         val conf = ConfigFactory.defaultOverrides()

config/src/test/scala/com/typesafe/config/impl/ConfigTest.scala

@@ -1207,6 +1207,35 @@ class ConfigTest extends TestUtils {
         }
     }
 
+    @Test
+    def renderShowEnvVariableValues(): Unit = {
+        val config = ConfigFactory.load("env-variables")
+        assertEquals("A", config.getString("secret"))
+        assertEquals("B", config.getStringList("secrets").get(0))
+        assertEquals("C", config.getStringList("secrets").get(1))
+        val hideRenderOpt = ConfigRenderOptions.defaults().setShowEnvVariableValues(false)
+        val rendered1 = config.root().render(hideRenderOpt)
+        assertTrue(rendered1.contains(""""secret" : "<env variable>""""))
+        assertTrue(rendered1.contains(
+            """|    "secrets" : [
+               |        # env variables
+               |        "<env variable>",
+               |        # env variables
+               |        "<env variable>"
+               |    ]""".stripMargin))
+
+        val showRenderOpt = ConfigRenderOptions.defaults()
+        val rendered2 = config.root().render(showRenderOpt)
+        assertTrue(rendered2.contains(""""secret" : "A""""))
+        assertTrue(rendered2.contains(
+            """|    "secrets" : [
+               |        # env variables
+               |        "B",
+               |        # env variables
+               |        "C"
+               |    ]""".stripMargin))
+    }
+
     @Test
     def serializeRoundTrip() {
         for (i <- 1 to 10) {