add ability to read text in addition to secrets

Author: jaymode

docs/reference/setup/configuration.asciidoc

@@ -265,25 +265,27 @@ file which will resolve to an environment setting, for example:
 --------------------------------------------------
 
 Additionally, for settings that you do not wish to store in the configuration
-file, you can use the value `__prompt__` and start Elasticsearch in the
-foreground.
+file, you can use the value `__prompt:text__` or `__prompt:secret__` and start
+Elasticsearch in the foreground. `__prompt:secret__` has echoing disabled so
+that the value entered will not be shown in your terminal; `__prompt:text__`
+will allow you to see the value as you type it in. For example:
 
 [source,yaml]
 --------------------------------------------------
 node:
-  name: __prompt__
+  name: __prompt:text__
 --------------------------------------------------
 
 On execution of the `elasticsearch` command, you will be prompted to enter
 the actual value like so:
 
 [source,sh]
 --------------------------------------------------
-Enter value for [node.name] :
+Enter value for [node.name]:
 --------------------------------------------------
 
-NOTE: Elasticsearch will not start if `__prompt__` is used in the settings
-and the process is run as a service or in the background.
+NOTE: Elasticsearch will not start if `__prompt:text__` or `__prompt:secret__`
+is used in the settings and the process is run as a service or in the background.
 
 The location of the configuration file can be set externally using a
 system property:

src/main/java/org/elasticsearch/common/property/PromptPlaceholderResolver.java

@@ -19,12 +19,12 @@
 
 package org.elasticsearch.node.internal;
 
+import com.google.common.collect.UnmodifiableIterator;
 import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.common.Names;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.collect.Tuple;
-import org.elasticsearch.common.property.PromptPlaceholderResolver;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
@@ -40,6 +40,9 @@
  */
 public class InternalSettingsPreparer {
 
+    public static final String SECRET_PROMPT_VALUE = "__prompt:secret__";
+    public static final String TEXT_PROMPT_VALUE = "__prompt:text__";
+
     /**
      * Prepares the settings by gathering all elasticsearch system properties, optionally loading the configuration settings,
      * and then replacing all property placeholders. This method will not work with settings that have <code>__prompt__</code>
@@ -153,7 +156,7 @@ public static Tuple<Settings, Environment> prepareSettings(Settings pSettings, b
             settingsBuilder.put(ClusterName.SETTING, ClusterName.DEFAULT.value());
         }
 
-        Settings v1 = PromptPlaceholderResolver.replacePromptPlaceholders(settingsBuilder.build(), terminal);
+        Settings v1 = replacePromptPlaceholders(settingsBuilder.build(), terminal);
         environment = new Environment(v1);
 
         // put back the env settings
@@ -165,4 +168,45 @@ public static Tuple<Settings, Environment> prepareSettings(Settings pSettings, b
 
         return new Tuple<>(v1, environment);
     }
+
+    static Settings replacePromptPlaceholders(Settings settings, Terminal terminal) {
+        UnmodifiableIterator<Map.Entry<String, String>> iter = settings.getAsMap().entrySet().iterator();
+        ImmutableSettings.Builder builder = ImmutableSettings.builder();
+
+        while (iter.hasNext()) {
+            Map.Entry<String, String> entry = iter.next();
+            String value = entry.getValue();
+            String key = entry.getKey();
+            switch (value) {
+                case SECRET_PROMPT_VALUE:
+                    String secretValue = promptForValue(key, terminal, true);
+                    if (Strings.hasLength(secretValue)) {
+                        builder.put(key, secretValue);
+                    }
+                    break;
+                case TEXT_PROMPT_VALUE:
+                    String textValue = promptForValue(key, terminal, false);
+                    if (Strings.hasLength(textValue)) {
+                        builder.put(key, textValue);
+                    }
+                    break;
+                default:
+                    builder.put(key, value);
+                    break;
+            }
+        }
+
+        return builder.build();
+    }
+
+    static String promptForValue(String key, Terminal terminal, boolean secret) {
+        if (terminal == null) {
+            throw new UnsupportedOperationException("found property [" + key + "] with value [" + (secret ? SECRET_PROMPT_VALUE : TEXT_PROMPT_VALUE) +"]. prompting for property values is only supported when running elasticsearch in the foreground");
+        }
+
+        if (secret) {
+            return new String(terminal.readSecret("Enter value for [%s]: ", key));
+        }
+        return terminal.readText("Enter value for [%s]: ", key);
+    }
 }

src/main/java/org/elasticsearch/node/internal/InternalSettingsPreparer.java

@@ -23,10 +23,9 @@
 import org.apache.commons.cli.CommandLine;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.Strings;
-import org.elasticsearch.common.property.PromptPlaceholderResolver;
-import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
+import org.elasticsearch.node.internal.InternalSettingsPreparer;
 import org.junit.Test;
 
 import java.io.IOException;
@@ -277,32 +276,44 @@ public CliTool.ExitStatus execute(Settings settings, Environment env) {
     @Test
     public void testPromptForSetting() throws Exception {
         final AtomicInteger counter = new AtomicInteger();
-        final AtomicReference<String> promptedValue = new AtomicReference<>(null);
+        final AtomicReference<String> promptedSecretValue = new AtomicReference<>(null);
+        final AtomicReference<String> promptedTextValue = new AtomicReference<>(null);
         final Terminal terminal = new MockTerminal() {
             @Override
             public char[] readSecret(String text, Object... args) {
                 counter.incrementAndGet();
                 assertThat(args, arrayContaining((Object) "foo.password"));
                 return "changeit".toCharArray();
             }
+
+            @Override
+            public String readText(String text, Object... args) {
+                counter.incrementAndGet();
+                assertThat(args, arrayContaining((Object) "replace"));
+                return "replaced";
+            }
         };
         final NamedCommand cmd = new NamedCommand("noop", terminal) {
             @Override
             public CliTool.ExitStatus execute(Settings settings, Environment env) {
-                promptedValue.set(settings.get("foo.password"));
+                promptedSecretValue.set(settings.get("foo.password"));
+                promptedTextValue.set(settings.get("replace"));
                 return CliTool.ExitStatus.OK;
             }
         };
 
-        System.setProperty("es.foo.password", PromptPlaceholderResolver.PROMPT_VALUE);
+        System.setProperty("es.foo.password", InternalSettingsPreparer.SECRET_PROMPT_VALUE);
+        System.setProperty("es.replace", InternalSettingsPreparer.TEXT_PROMPT_VALUE);
         try {
             new SingleCmdTool("tool", terminal, cmd).execute();
         } finally {
             System.clearProperty("es.foo.password");
+            System.clearProperty("es.replace");
         }
 
-        assertThat(counter.intValue(), is(1));
-        assertThat(promptedValue.get(), is("changeit"));
+        assertThat(counter.intValue(), is(2));
+        assertThat(promptedSecretValue.get(), is("changeit"));
+        assertThat(promptedTextValue.get(), is("replaced"));
     }
 
     private void assertStatus(int status, CliTool.ExitStatus expectedStatus) {