Add jdbc_tracing configuration option to control Snowflake JDBC driver logging

- Add jdbc_tracing parameter to SnowflakePluginTask interface with default value "INFO"
- Set tracing property in JDBC connection properties based on configuration
- Update README documentation with new configuration option
- Allows users to control verbosity of Snowflake JDBC driver logs (OFF, SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST, ALL)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: kentoyoshida

README.md

@@ -25,6 +25,7 @@ Snowflake output plugin for Embulk loads records to Snowflake.
 - **max_retry_wait**: upper limit of retry wait, which will be doubled at every retry (integer, default: 1800000 (30 minutes))
 - **max_upload_retries**: maximum number of retries for file upload to Snowflake (integer, default: 3).
 - **max_copy_retries**: maximum number of retries for COPY operations in Snowflake (integer, default: 3). Retries occur when transient errors such as communication failures happen during the COPY process.
+- **jdbc_tracing**: JDBC driver logging level. This controls the verbosity of Snowflake JDBC driver logs. Valid values are: OFF, SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST, ALL (string, default: "INFO").
 - **mode**: "insert", "insert_direct", "truncate_insert", "replace" or "merge". See below. (string, required)
 - **merge_keys**: key column names for merging records in merge mode (string array, required in merge mode if table doesn't have primary key)
 - **merge_rule**: list of column assignments for updating existing records used in merge mode, for example `"foo" = T."foo" + S."foo"` (`T` means target table and `S` means source table). (string array, default: always overwrites with new values)

src/main/java/org/embulk/output/SnowflakeOutputPlugin.java

@@ -91,6 +91,10 @@ public interface SnowflakePluginTask extends PluginTask {
     @ConfigDefault("\"none\"")
     public MatchByColumnName getMatchByColumnName();
 
+    @Config("jdbc_tracing")
+    @ConfigDefault("\"INFO\"")
+    public String getJdbcTracing();
+
     public void setCopyIntoTableColumnNames(String[] columnNames);
 
     public String[] getCopyIntoTableColumnNames();
@@ -198,6 +202,8 @@ protected JdbcOutputConnector getConnector(PluginTask task, boolean retryableMet
     props.setProperty("CLIENT_METADATA_REQUEST_USE_CONNECTION_CTX", "true");
     props.setProperty("MULTI_STATEMENT_COUNT", "0");
 
+    props.setProperty("tracing", t.getJdbcTracing());
+
     props.putAll(t.getOptions());
 
     logConnectionProperties(url, props);