Making file extension mandatory (#69)

File extension is optional parameter but when we try to process parquet file using CsvFileIngestService class, it throws parsing error when it tries to process parquet file.

pravega-sensor-collector/src/main/java/io/pravega/sensor/collector/DeviceDriver.java

@@ -39,7 +39,7 @@ public DeviceDriver(DeviceDriverConfig config) {
     public String getProperty(String key) {
         final String value = config.getProperties().get(key);
         if (value == null || value.isEmpty()) {
-            throw new IllegalArgumentException(MessageFormat.format("Missing required parameter {0}", key));
+            throw new IllegalArgumentException(MessageFormat.format("PSC Service Error: Missing required parameter {0} in config", key));
         }
         return value;
     }

pravega-sensor-collector/src/main/java/io/pravega/sensor/collector/file/FileIngestService.java

@@ -99,7 +99,7 @@ String getFileSpec() {
         return getProperty(FILE_SPEC_KEY);
     }
     String getFileExtension() {
-        return getProperty(FILE_EXT, "");
+        return getProperty(FILE_EXT);
     }
 
     boolean getDeleteCompletedFiles() {