refactoring ConfigHelper and ConfigurationSources to simplify code readability and hide supported-configuration details

Author: mhlidd

utils/config-utils/src/main/java/datadog/trace/config/inversion/ConfigHelper.java

@@ -82,32 +82,29 @@ public Map<String, String> getEnvironmentVariables() {
     for (Map.Entry<String, String> entry : env.entrySet()) {
       String key = entry.getKey();
       String value = entry.getValue();
-      Map<String, String> aliasMapping = configSource.getAliasMapping();
-      if (key.startsWith("DD_") || key.startsWith("OTEL_") || aliasMapping.containsKey(key)) {
-        String baseConfig;
-        if (configSource.getSupportedConfigurations().contains(key)) {
+      String primaryEnv = configSource.primaryEnvFromAlias(key);
+      if (key.startsWith("DD_") || key.startsWith("OTEL_") || null != primaryEnv) {
+        if (configSource.supported(key)) {
           configs.put(key, value);
           // If this environment variable is the alias of another, and we haven't processed the
           // original environment variable yet, handle it here.
-        } else if (aliasMapping.containsKey(key)
-            && !configs.containsKey(baseConfig = aliasMapping.get(key))) {
-          List<String> aliasList = configSource.getAliases().get(baseConfig);
-          for (String alias : aliasList) {
+        } else if (null != primaryEnv && !configs.containsKey(primaryEnv)) {
+          List<String> aliases = configSource.getAliases(primaryEnv);
+          for (String alias : aliases) {
             if (env.containsKey(alias)) {
-              configs.put(baseConfig, env.get(alias));
+              configs.put(primaryEnv, env.get(alias));
               break;
             }
           }
         }
-        // TODO: Follow-up - Add deprecation handling
-        if (configSource.getDeprecatedConfigurations().containsKey(key)) {
+        String envFromDeprecated;
+        if ((envFromDeprecated = configSource.primaryEnvFromDeprecated(key)) != null) {
           String warning =
               "Environment variable "
                   + key
-                  + " is deprecated. "
-                  + (configSource.getAliasMapping().containsKey(key)
-                      ? "Please use " + configSource.getAliasMapping().get(key) + " instead."
-                      : configSource.getDeprecatedConfigurations().get(key));
+                  + " is deprecated. Please use "
+                  + (primaryEnv != null ? primaryEnv : envFromDeprecated)
+                  + " instead.";
           log.warn(warning);
         }
       } else {
@@ -123,8 +120,8 @@ public String getEnvironmentVariable(String name) {
     }
 
     if ((name.startsWith("DD_") || name.startsWith("OTEL_"))
-        && !configSource.getAliasMapping().containsKey(name)
-        && !configSource.getSupportedConfigurations().contains(name)) {
+        && null != configSource.primaryEnvFromAlias(name)
+        && !configSource.supported(name)) {
       if (configInversionStrict != StrictnessPolicy.TEST) {
         ConfigInversionMetricCollectorProvider.get().setUndocumentedEnvVarMetric(name);
       }
@@ -136,7 +133,7 @@ public String getEnvironmentVariable(String name) {
 
     String config = EnvironmentVariables.get(name);
     List<String> aliases;
-    if (config == null && (aliases = configSource.getAliases().get(name)) != null) {
+    if (config == null && (aliases = configSource.getAliases(name)) != null) {
       for (String alias : aliases) {
         String aliasValue = EnvironmentVariables.get(alias);
         if (aliasValue != null) {

utils/config-utils/src/main/java/datadog/trace/config/inversion/SupportedConfigurationSource.java

@@ -1,32 +1,30 @@
 package datadog.trace.config.inversion;
 
 import java.util.List;
-import java.util.Map;
-import java.util.Set;
 
 /**
  * This class uses {@link #GeneratedSupportedConfigurations} for handling supported configurations
  * for Config Inversion Can be extended for testing with custom configuration data.
  */
 class SupportedConfigurationSource {
 
-  /** @return Set of supported configuration keys */
-  public Set<String> getSupportedConfigurations() {
-    return GeneratedSupportedConfigurations.SUPPORTED;
+  /** @return Set of supported environment variable keys */
+  public boolean supported(String env) {
+    return GeneratedSupportedConfigurations.SUPPORTED.contains(env);
   }
 
-  /** @return Map of configuration keys to their aliases */
-  public Map<String, List<String>> getAliases() {
-    return GeneratedSupportedConfigurations.ALIASES;
+  /** @return List of aliases for an environment variable */
+  public List<String> getAliases(String env) {
+    return GeneratedSupportedConfigurations.ALIASES.getOrDefault(env, null);
   }
 
-  /** @return Map of alias keys to their primary configuration keys */
-  public Map<String, String> getAliasMapping() {
-    return GeneratedSupportedConfigurations.ALIAS_MAPPING;
+  /** @return Primary environment variable for a queried alias */
+  public String primaryEnvFromAlias(String alias) {
+    return GeneratedSupportedConfigurations.ALIAS_MAPPING.getOrDefault(alias, null);
   }
 
   /** @return Map of deprecated configurations */
-  public Map<String, String> getDeprecatedConfigurations() {
-    return GeneratedSupportedConfigurations.DEPRECATED;
+  public String primaryEnvFromDeprecated(String deprecated) {
+    return GeneratedSupportedConfigurations.DEPRECATED.getOrDefault(deprecated, null);
   }
 }

utils/config-utils/src/test/java/datadog/trace/config/inversion/TestSupportedConfigurationSource.java

@@ -23,22 +23,22 @@ public TestSupportedConfigurationSource(
   }
 
   @Override
-  public Set<String> getSupportedConfigurations() {
-    return supported;
+  public boolean supported(String env) {
+    return supported.contains(env);
   }
 
   @Override
-  public Map<String, List<String>> getAliases() {
-    return aliases;
+  public List<String> getAliases(String env) {
+    return aliases.getOrDefault(env, null);
   }
 
   @Override
-  public Map<String, String> getAliasMapping() {
-    return aliasMapping;
+  public String primaryEnvFromAlias(String alias) {
+    return aliasMapping.getOrDefault(alias, null);
   }
 
   @Override
-  public Map<String, String> getDeprecatedConfigurations() {
-    return deprecated;
+  public String primaryEnvFromDeprecated(String deprecated) {
+    return this.deprecated.getOrDefault(deprecated, null);
   }
 }