Add generic object type configuration support to Configurator (NationalSecurityAgency#1344)

Author: rcameronm

src/main/java/emissary/config/Configurator.java

@@ -4,6 +4,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Function;
 
 /**
  * Interface for dealing with configured properties
@@ -174,7 +175,7 @@ public interface Configurator {
     long findLongEntry(String param, long dflt);
 
     /**
-     * Find config entry as an double
+     * Find config entry as a double
      *
      * @param param name of config entry
      * @param dflt default value when none found
@@ -183,7 +184,7 @@ public interface Configurator {
     double findDoubleEntry(String param, double dflt);
 
     /**
-     * Find config entry as an boolean
+     * Find config entry as a boolean
      *
      * @param param name of config entry
      * @param dflt default value when none found
@@ -193,14 +194,25 @@ public interface Configurator {
 
 
     /**
-     * Find config entry as an boolean
+     * Find config entry as a boolean
      *
      * @param param name of config entry
      * @param dflt default value when none found
      * @return boolean value or dflt when none found or not a boolean
      */
     boolean findBooleanEntry(String param, String dflt);
 
+    /**
+     * Find config entry as a generic Object
+     *
+     * @param param name of config entry
+     * @param parser method to turn entry from String into the correct type
+     * @param dflt default value when none found
+     * @return object value or dflt when none found or not the right type
+     * @param <T> the type of the return object
+     */
+    <T> T findObjectEntry(String param, Function<String, T> parser, T dflt);
+
     /**
      * Get the names of all entries for this config. This set is not backed by the configuration and any changes to it are
      * not relflected in the configuration.

src/main/java/emissary/config/ServiceConfigGuide.java

@@ -33,6 +33,7 @@
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
+import java.util.function.Function;
 
 /**
  * This class implements the Configurator interface for services within the Emissary framework.
@@ -1157,6 +1158,25 @@ public boolean findBooleanEntry(final String theParameter, final String dflt) {
         return findBooleanEntry(theParameter, Boolean.parseBoolean(dflt));
     }
 
+    /**
+     * Return the first entry matching the key parameter or the default if no match is found
+     *
+     * @param theParameter the key to match
+     * @param parser method to turn the matched value from a String into the correct type
+     * @param dflt the value to use when no matches are found
+     * @return the first matching value or the default when none found
+     * @param <T> the expected return type
+     */
+    @Override
+    public <T> T findObjectEntry(String theParameter, Function<String, T> parser, T dflt) {
+        final List<String> matchingEntries = findEntries(theParameter);
+        if (!matchingEntries.isEmpty()) {
+            String el = matchingEntries.get(0);
+            return parser.apply(el);
+        }
+        return dflt;
+    }
+
     /**
      * Get the value of a parameter that is purported to be numeric
      *

src/main/java/emissary/grpc/pool/ConnectionFactory.java

@@ -115,8 +115,8 @@ public ConnectionFactory(String host, int port, Configurator configG,
 
         // Specifies how the client chooses between multiple backend addresses
         // e.g. "pick_first" uses the first address only, "round_robin" cycles through all of them for client-side balancing
-        this.loadBalancingPolicy = LoadBalancingPolicy.getPolicyName(
-                configG.findStringEntry(GRPC_LOAD_BALANCING_POLICY), LoadBalancingPolicy.ROUND_ROBIN);
+        this.loadBalancingPolicy = configG.findObjectEntry(
+                GRPC_LOAD_BALANCING_POLICY, LoadBalancingPolicy::valueOf, LoadBalancingPolicy.ROUND_ROBIN).formattedName();
 
         // Max size (in bytes) for incoming messages and message metadata from the server
         this.maxInboundMessageByteSize = configG.findIntEntry(GRPC_MAX_INBOUND_MESSAGE_BYTE_SIZE, 4 << 20); // 4 MiB
@@ -142,8 +142,9 @@ public ConnectionFactory(String host, int port, Configurator configG,
         this.poolConfig.setMaxTotal(configG.findIntEntry(GRPC_POOL_MAX_SIZE, 8));
 
         // Order for pool to borrow connections
-        this.poolConfig.setLifo(PoolRetrievalOrdering.isLifo(
-                configG.findStringEntry(GRPC_POOL_RETRIEVAL_ORDER), PoolRetrievalOrdering.LIFO));
+        PoolRetrievalOrdering retrievalOrdering = configG.findObjectEntry(
+                GRPC_POOL_RETRIEVAL_ORDER, PoolRetrievalOrdering::valueOf, PoolRetrievalOrdering.LIFO);
+        this.poolConfig.setLifo(retrievalOrdering.equals(PoolRetrievalOrdering.LIFO));
 
         // Whether to validate channels when borrowing from the pool
         this.poolConfig.setTestOnBorrow(configG.findBooleanEntry(GRPC_POOL_TEST_BEFORE_BORROW, true));

src/main/java/emissary/grpc/pool/LoadBalancingPolicy.java

@@ -5,17 +5,7 @@
 public enum LoadBalancingPolicy {
     ROUND_ROBIN, PICK_FIRST;
 
-    public static LoadBalancingPolicy getPolicy(String input, LoadBalancingPolicy defaultPolicy) {
-        if (input == null) {
-            return defaultPolicy;
-        }
-        return LoadBalancingPolicy.valueOf(input.toUpperCase(Locale.ROOT));
-    }
-
-    public static String getPolicyName(String input, LoadBalancingPolicy defaultPolicy) {
-        return LoadBalancingPolicy
-                .getPolicy(input, defaultPolicy)
-                .name()
-                .toLowerCase(Locale.ROOT);
+    public String formattedName() {
+        return name().toLowerCase(Locale.ROOT);
     }
 }

src/main/java/emissary/grpc/pool/PoolRetrievalOrdering.java

@@ -1,22 +1,5 @@
 package emissary.grpc.pool;
 
-import java.util.Locale;
-
 public enum PoolRetrievalOrdering {
     LIFO, FIFO;
-
-    public static PoolRetrievalOrdering getOrder(String input, PoolRetrievalOrdering defaultOrdering) {
-        if (input == null) {
-            return defaultOrdering;
-        }
-        return PoolRetrievalOrdering.valueOf(input.toUpperCase(Locale.ROOT));
-    }
-
-    public static boolean isLifo(String order, PoolRetrievalOrdering defaultOrdering) {
-        return PoolRetrievalOrdering.getOrder(order, defaultOrdering) == LIFO;
-    }
-
-    public static boolean isFifo(String order, PoolRetrievalOrdering defaultOrdering) {
-        return PoolRetrievalOrdering.getOrder(order, defaultOrdering) == FIFO;
-    }
 }

src/test/java/emissary/config/ServiceConfigGuideTest.java

@@ -310,7 +310,8 @@ void testEntryPrimitives() throws IOException {
                         + "BOOLEANQ = \"BOGUS\"\n" + "SZP = \"123\"\n" + "SZB = \"123b\"\n" + "SZK = \"123k\"\n" + "SZM = \"123m\"\n"
                         + "SZG = \"123g\"\n" + "SZT = \"123t\"\n" + "SZQ = \"red balloons\"\n" + "SZ1 = \"111\"\n" + "SZ2 = \"222\"\n"
                         + "SZ3 = \"333\"\n" + "SZ4 = \"444\"\n" + "SZ5 = \"555\"\n" + "SZ6 = \"666\"\n" + "SZ7 = \"777\"\n" + "SZ8 = \"888\"\n"
-                        + "SZ9 = \"999\"\n" + "SZ0 = \"000\"\n" + "STRING = \"chars\"\n" + "LONG2 = 12345678901234").getBytes();
+                        + "SZ9 = \"999\"\n" + "SZ0 = \"000\"\n" + "STRING = \"chars\"\n" + "LONG2 = 12345678901234\n"
+                        + "OBJECTM = \"MATCH_VALUE\"\n").getBytes();
         final ByteArrayInputStream str = new ByteArrayInputStream(configData);
         final Configurator c = ConfigUtil.getConfigInfo(str);
         assertEquals(123, c.findIntEntry("INTEGER", 456), "Int entry with def");
@@ -352,6 +353,9 @@ void testEntryPrimitives() throws IOException {
         assertEquals(888L, c.findSizeEntry("SZ8", -1L), "Size digit check");
         assertEquals(999L, c.findSizeEntry("SZ9", -1L), "Size digit check");
         assertEquals(0L, c.findSizeEntry("SZ0", -1L), "Size digit check");
+
+        assertEquals(TestType.MATCH_VALUE, c.findObjectEntry("OBJECTM", TestType::valueOf, TestType.DEFAULT_VALUE));
+        assertEquals(TestType.DEFAULT_VALUE, c.findObjectEntry("OBJECTD", TestType::valueOf, TestType.DEFAULT_VALUE));
     }
 
     @Test
@@ -699,4 +703,7 @@ void testFindStringMatchMultiMapOrdered(boolean preserveCase) {
 
     }
 
+    private enum TestType {
+        DEFAULT_VALUE, MATCH_VALUE
+    }
 }

src/test/java/emissary/grpc/pool/ConnectionFactoryTest.java

@@ -70,7 +70,7 @@ void testFifoPoolRetrievalOrderConfig() {
     @Test
     void testBadLoadBalancingConfig() {
         Configurator configT = getDefaultConfigs();
-        configT.addEntry(ConnectionFactory.GRPC_LOAD_BALANCING_POLICY, "bad_scheduler");
+        configT.addEntry(ConnectionFactory.GRPC_LOAD_BALANCING_POLICY, "BAD_SCHEDULER");
         IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
                 () -> buildConnectionFactory(configT));
         assertEquals("No enum constant emissary.grpc.pool.LoadBalancingPolicy.BAD_SCHEDULER", e.getMessage());