feat: support for HTTP transport

connector/src/main/java/io/questdb/kafka/BufferingSender.java

@@ -4,6 +4,8 @@
 import io.questdb.std.BoolList;
 import io.questdb.std.LongList;
 
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
@@ -96,17 +98,22 @@ public Sender boolColumn(CharSequence name, boolean value) {
     }
 
     @Override
-    public Sender timestampColumn(CharSequence name, long value) {
+    public Sender timestampColumn(CharSequence name, long value, ChronoUnit unit) {
         if (symbolColumns.contains(name)) {
             symbolColumnNames.add(name);
             symbolColumnValues.add(String.valueOf(value));
         } else {
             timestampNames.add(name);
-            timestampValues.add(value);
+            timestampValues.add(unitToMicros(value, unit));
         }
         return this;
     }
 
+    @Override
+    public Sender timestampColumn(CharSequence charSequence, Instant instant) {
+        return null;
+    }
+
     @Override
     public Sender symbol(CharSequence name, CharSequence value) {
         symbolColumnNames.add(name);
@@ -164,16 +171,36 @@ private void transferFields() {
         for (int i = 0, n = timestampNames.size(); i < n; i++) {
             CharSequence fieldName = timestampNames.get(i);
             long fieldValue = timestampValues.get(i);
-            sender.timestampColumn(fieldName, fieldValue);
+            sender.timestampColumn(fieldName, fieldValue, ChronoUnit.MICROS);
         }
         timestampNames.clear();
         timestampValues.clear();
     }
 
+    private static long unitToMicros(long value, ChronoUnit unit) {
+        switch (unit) {
+            case NANOS:
+                return value / 1000L;
+            case MICROS:
+                return value;
+            case MILLIS:
+                return value * 1000L;
+            case SECONDS:
+                return value * 1_000_000L;
+            default:
+                throw new IllegalArgumentException("Unsupported unit: " + unit);
+        }
+    }
+
     @Override
-    public void at(long timestamp) {
+    public void at(long timestamp, ChronoUnit unit) {
         transferFields();
-        sender.at(timestamp);
+        sender.at(timestamp, unit);
+    }
+
+    @Override
+    public void at(Instant instant) {
+        throw new UnsupportedOperationException();
     }
 
     @Override

connector/src/main/java/io/questdb/kafka/QuestDBSinkConnectorConfig.java

@@ -61,6 +61,9 @@ public final class QuestDBSinkConnectorConfig extends AbstractConfig {
     public static final String TLS_VALIDATION_MODE_CONFIG = "tls.validation.mode";
     public static final String TLS_VALIDATION_MODE_DOC = "TLS validation mode. Possible values: default, insecure";
 
+    public static final String CONFIGURATION_STRING_CONFIG = "client.conf.string";
+    public static final String CONFIGURATION_STRING_DOC = "Configuration string for QuestDB client";
+
     public static final String RETRY_BACKOFF_MS = "retry.backoff.ms";
     private static final String RETRY_BACKOFF_MS_DOC = "The time in milliseconds to wait following an error before a retry attempt is made";
 
@@ -70,15 +73,6 @@ public final class QuestDBSinkConnectorConfig extends AbstractConfig {
     public static final String TIMESTAMP_FORMAT = "timestamp.string.format";
     private static final String TIMESTAMP_FORMAT_DOC = "Timestamp format. Used when parsing timestamp string fields";
 
-    public static final String DEDUPLICATION_REWIND_CONFIG = "dedup.rewind.offset";
-    private static final String DEDUPLICATION_REWIND_DOC = "Rewind offset for deduplication. " +
-            "On failure, the connector will rewind the offset by this amount and retry. This is designed to work in concert with QuestDB " +
-            "deduplication feature. The rewind offset must be greater than or equal to the maximum number of records that can lost in the event of a failure. " +
-            "If the rewind is too small, some events might be missing from QuestDB. If the rewind is too large, the connector will be slower to recover " +
-            "as it will have to reprocess a large number of records and QuestDB will have to do extra work with deduplication. If you are testing this " +
-            "feature for the first time then 150000 is a good starting point.";
-
-
     private static final String DEFAULT_TIMESTAMP_FORMAT = "yyyy-MM-ddTHH:mm:ss.SSSUUUZ";
 
     public QuestDBSinkConnectorConfig(ConfigDef config, Map<String, String> parsedConfig) {
@@ -91,7 +85,7 @@ public QuestDBSinkConnectorConfig(Map<String, String> parsedConfig) {
 
     public static ConfigDef conf() {
         return new ConfigDef()
-                .define(HOST_CONFIG, Type.STRING, Importance.HIGH, HOST_DOC)
+                .define(HOST_CONFIG, Type.STRING, null, Importance.HIGH, HOST_DOC)
                 .define(TABLE_CONFIG, Type.STRING, null, TablenameValidator.INSTANCE, Importance.HIGH, TABLE_DOC)
                 .define(KEY_PREFIX_CONFIG, Type.STRING, "key", Importance.MEDIUM, KEY_PREFIX_DOC)
                 .define(VALUE_PREFIX_CONFIG, Type.STRING, "", Importance.MEDIUM, VALUE_PREFIX_DOC)
@@ -109,12 +103,12 @@ public static ConfigDef conf() {
                 .define(TIMESTAMP_FORMAT, Type.STRING, DEFAULT_TIMESTAMP_FORMAT, TimestampFormatValidator.INSTANCE, Importance.MEDIUM, TIMESTAMP_FORMAT_DOC)
                 .define(TIMESTAMP_STRING_FIELDS, Type.STRING, null, Importance.MEDIUM, TIMESTAMP_STRING_FIELDS_DOC)
                 .define(DESIGNATED_TIMESTAMP_KAFKA_NATIVE_CONFIG, Type.BOOLEAN, false, Importance.MEDIUM, DESIGNATED_TIMESTAMP_KAFKA_NATIVE_DOC)
-                .define(DEDUPLICATION_REWIND_CONFIG, Type.LONG, 0, Importance.MEDIUM, DEDUPLICATION_REWIND_DOC)
-                .define(TLS_VALIDATION_MODE_CONFIG, Type.STRING, "default", ConfigDef.ValidString.in("default", "insecure"), Importance.LOW, TLS_VALIDATION_MODE_DOC);
+                .define(TLS_VALIDATION_MODE_CONFIG, Type.STRING, "default", ConfigDef.ValidString.in("default", "insecure"), Importance.LOW, TLS_VALIDATION_MODE_DOC)
+                .define(CONFIGURATION_STRING_CONFIG, Type.STRING, null, Importance.HIGH, CONFIGURATION_STRING_DOC);
     }
 
-    public long getDeduplicationRewindOffset() {
-        return getLong(DEDUPLICATION_REWIND_CONFIG);
+    public String getConfigurationString() {
+        return getString(CONFIGURATION_STRING_CONFIG);
     }
 
     public String getTlsValidationMode() {