[cdc-cli][cdc-dist] Support loading global config from FLINK_CDC_HOME (#2822)

This closes #2822.

flink-cdc-cli/src/main/java/com/ververica/cdc/cli/CliFrontend.java

@@ -42,6 +42,7 @@ import java.util.stream.Collectors;
 public class CliFrontend {
     private static final Logger LOG = LoggerFactory.getLogger(CliFrontend.class);
     private static final String FLINK_HOME_ENV_VAR = "FLINK_HOME";
+    private static final String FLINK_CDC_HOME_ENV_VAR = "FLINK_CDC_HOME";
 
     public static void main(String[] args) throws Exception {
         Options cliOptions = CliFrontendOptions.initializeOptions();
@@ -127,11 +128,27 @@ public class CliFrontend {
     }
 
     private static Configuration getGlobalConfig(CommandLine commandLine) throws Exception {
+        // Try to get global config path from command line
         String globalConfig = commandLine.getOptionValue(CliFrontendOptions.GLOBAL_CONFIG);
-        if (globalConfig == null) {
-            return new Configuration();
+        if (globalConfig != null) {
+            Path globalConfigPath = Paths.get(globalConfig);
+            LOG.info("Using global config in command line: {}", globalConfigPath);
+            return ConfigurationUtils.loadMapFormattedConfig(globalConfigPath);
+        }
+
+        // Fallback to Flink CDC home
+        String flinkCdcHome = System.getenv(FLINK_CDC_HOME_ENV_VAR);
+        if (flinkCdcHome != null) {
+            Path globalConfigPath =
+                    Paths.get(flinkCdcHome).resolve("conf").resolve("flink-cdc.yaml");
+            LOG.info("Using global config in FLINK_CDC_HOME: {}", globalConfigPath);
+            return ConfigurationUtils.loadMapFormattedConfig(globalConfigPath);
         }
-        return ConfigurationUtils.loadMapFormattedConfig(Paths.get(globalConfig));
+
+        // Fallback to empty configuration
+        LOG.warn(
+                "Cannot find global configuration in command-line or FLINK_CDC_HOME. Will use empty global configuration.");
+        return new Configuration();
     }
 
     private static void printExecutionInfo(PipelineExecution.ExecutionInfo info) {

flink-cdc-cli/src/main/java/com/ververica/cdc/cli/parser/YamlPipelineDefinitionParser.java

@@ -148,7 +148,7 @@ public class YamlPipelineDefinitionParser implements PipelineDefinitionParser {
     }
 
     private Configuration toPipelineConfig(JsonNode pipelineConfigNode) {
-        if (pipelineConfigNode == null) {
+        if (pipelineConfigNode == null || pipelineConfigNode.isNull()) {
             return new Configuration();
         }
         Map<String, String> pipelineConfigMap =

flink-cdc-dist/src/main/flink-cdc-bin/bin/flink-cdc.sh

@@ -44,6 +44,7 @@ FLINK_CONF_DIR=$FLINK_HOME/conf
 # Define Flink CDC directories
 SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 FLINK_CDC_HOME="$SCRIPT_DIR"/..
+export FLINK_CDC_HOME=$FLINK_CDC_HOME
 FLINK_CDC_CONF="$FLINK_CDC_HOME"/conf
 FLINK_CDC_LIB="$FLINK_CDC_HOME"/lib
 FLINK_CDC_LOG="$FLINK_CDC_HOME"/log

flink-cdc-dist/src/main/flink-cdc-bin/conf/flink-cdc.yaml

@@ -1,14 +1,20 @@
-<!--
-  Copyright 2023 Ververica Inc.
+################################################################################
+#  Copyright 2023 Ververica Inc.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#  http://www.apache.org/licenses/LICENSE-2.0
+#  Unless required by applicable law or agreed to in writing,
+#  software distributed under the License is distributed on an
+#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+################################################################################
 
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-  http://www.apache.org/licenses/LICENSE-2.0
-  Unless required by applicable law or agreed to in writing,
-  software distributed under the License is distributed on an
-  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-  KIND, either express or implied.  See the License for the
-  specific language governing permissions and limitations
-  under the License.
-  -->
+# Parallelism of the pipeline
+parallelism: 4
+
+# Behavior for handling schema change events from source
+schema.change.behavior: EVOLVE