Github user mattyb149 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/642#discussion_r71093459
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/ListDatabaseTables.java
---
@@ -0,0 +1,304 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+package org.apache.nifi.processors.standard;
+
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.Stateful;
+import org.apache.nifi.annotation.behavior.TriggerSerially;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.Validator;
+import org.apache.nifi.components.state.Scope;
+import org.apache.nifi.components.state.StateManager;
+import org.apache.nifi.components.state.StateMap;
+import org.apache.nifi.dbcp.DBCPService;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.util.StringUtils;
+
+import java.io.IOException;
+import java.sql.Connection;
+import java.sql.DatabaseMetaData;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * A processor to retrieve a list of tables (and their metadata) from a
database connection
+ */
+@TriggerSerially
+@InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN)
+@Tags({"sql", "list", "jdbc", "table", "database"})
+@CapabilityDescription("Generates a set of flow files, each containing
attributes corresponding to metadata about a table from a database connection.")
+@WritesAttributes({
+ @WritesAttribute(attribute = "db.table.name", description =
"Contains the name of a database table from the connection"),
+ @WritesAttribute(attribute = "db.table.catalog", description =
"Contains the name of the catalog to which the table belongs (may be null)"),
+ @WritesAttribute(attribute = "db.table.schema", description =
"Contains the name of the schema to which the table belongs (may be null)"),
+ @WritesAttribute(attribute = "db.table.fullname", description =
"Contains the fully-qualifed table name (possibly including catalog, schema,
etc.)"),
+ @WritesAttribute(attribute = "db.table.type",
+ description = "Contains the type of the database table
from the connection. Typical types are \"TABLE\", \"VIEW\", \"SYSTEM TABLE\", "
+ + "\"GLOBAL TEMPORARY\", \"LOCAL TEMPORARY\",
\"ALIAS\", \"SYNONYM\""),
+ @WritesAttribute(attribute = "db.table.remarks", description =
"Contains the name of a database table from the connection"),
+ @WritesAttribute(attribute = "db.table.count", description =
"Contains the number of rows in the table")
+})
+@Stateful(scopes = {Scope.LOCAL}, description = "After performing a
listing of tables, the timestamp of the query is stored. "
+ + "This allows the Processor to not re-list tables the next time
that the Processor is run. Changing any of the processor properties will "
+ + "indicate that the processor should reset state and thus re-list
the tables using the new configuration. This processor is meant to be "
+ + "run on the primary node only.")
+public class ListDatabaseTables extends AbstractProcessor {
+
+ // Attribute names
+ public static final String DB_TABLE_NAME = "db.table.name";
+ public static final String DB_TABLE_CATALOG = "db.table.catalog";
+ public static final String DB_TABLE_SCHEMA = "db.table.schema";
+ public static final String DB_TABLE_FULLNAME = "db.table.fullname";
+ public static final String DB_TABLE_TYPE = "db.table.type";
+ public static final String DB_TABLE_REMARKS = "db.table.remarks";
+ public static final String DB_TABLE_COUNT = "db.table.count";
+
+ // Relationships
+ public static final Relationship REL_SUCCESS = new
Relationship.Builder()
+ .name("success")
+ .description("All FlowFiles that are received are routed to
success")
+ .build();
+
+ // Property descriptors
+ public static final PropertyDescriptor DBCP_SERVICE = new
PropertyDescriptor.Builder()
+ .name("list-db-tables-db-connection")
+ .displayName("Database Connection Pooling Service")
+ .description("The Controller Service that is used to obtain
connection to database")
+ .required(true)
+ .identifiesControllerService(DBCPService.class)
+ .build();
+
+ public static final PropertyDescriptor CATALOG = new
PropertyDescriptor.Builder()
+ .name("list-db-tables-catalog")
+ .displayName("Catalog")
+ .description("The name of a catalog from which to list
database tables. The name must match the catalog name as it is stored in the
database. "
+ + "If the property is not set, the catalog name will
not be used to narrow the search for tables. If the property is set to an empty
string, "
+ + "tables without a catalog will be listed.")
+ .required(false)
+ .addValidator(Validator.VALID)
+ .build();
+
+ public static final PropertyDescriptor SCHEMA_PATTERN = new
PropertyDescriptor.Builder()
+ .name("list-db-tables-schema-pattern")
+ .displayName("Schema Pattern")
+ .description("A pattern for matching schemas in the database.
Within a pattern, \"%\" means match any substring of 0 or more characters, "
+ + "and \"_\" means match any one character. The
pattern must match the schema name as it is stored in the database. "
+ + "If the property is not set, the schema name will
not be used to narrow the search for tables. If the property is set to an empty
string, "
+ + "tables without a schema will be listed.")
+ .required(false)
+ .addValidator(Validator.VALID)
+ .build();
+
+ public static final PropertyDescriptor TABLE_NAME_PATTERN = new
PropertyDescriptor.Builder()
+ .name("list-db-tables-name-pattern")
+ .displayName("Table Name Pattern")
+ .description("A pattern for matching tables in the database.
Within a pattern, \"%\" means match any substring of 0 or more characters, "
+ + "and \"_\" means match any one character. The
pattern must match the table name as it is stored in the database. "
+ + "If the property is not set, all tables will be
retrieved.")
+ .required(false)
+ .addValidator(Validator.VALID)
+ .build();
+
+ public static final PropertyDescriptor TABLE_TYPES = new
PropertyDescriptor.Builder()
+ .name("list-db-tables-types")
+ .displayName("Table Types")
+ .description("A comma-separated list of table types to
include. For example, some databases support TABLE and VIEW types. If the
property is not set, "
+ + "tables of all types will be returned.")
+ .required(false)
+ .defaultValue("TABLE")
+ .addValidator(Validator.VALID)
+ .build();
+
+ public static final PropertyDescriptor INCLUDE_COUNT = new
PropertyDescriptor.Builder()
+ .name("list-db-include-count")
+ .displayName("Include Count")
+ .description("Whether to include the table's row count as a
flow file attribute. This affects performance as a database query will be
generated "
+ + "for each table in the retrieved list.")
+ .required(true)
+ .allowableValues("true", "false")
+ .defaultValue("false")
+ .build();
+
+ private static final List<PropertyDescriptor> propertyDescriptors;
+ private static final Set<Relationship> relationships;
+
+ private boolean resetState = false;
+
+ /*
+ * Will ensure that the list of property descriptors is build only
once.
+ * Will also create a Set of relationships
+ */
+ static {
+ List<PropertyDescriptor> _propertyDescriptors = new ArrayList<>();
+ _propertyDescriptors.add(DBCP_SERVICE);
+ _propertyDescriptors.add(CATALOG);
+ _propertyDescriptors.add(SCHEMA_PATTERN);
+ _propertyDescriptors.add(TABLE_NAME_PATTERN);
+ _propertyDescriptors.add(TABLE_TYPES);
+ _propertyDescriptors.add(INCLUDE_COUNT);
+ propertyDescriptors =
Collections.unmodifiableList(_propertyDescriptors);
+
+ Set<Relationship> _relationships = new HashSet<>();
+ _relationships.add(REL_SUCCESS);
+ relationships = Collections.unmodifiableSet(_relationships);
+ }
+
+ @Override
+ protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+ return propertyDescriptors;
+ }
+
+ @Override
+ public Set<Relationship> getRelationships() {
+ return relationships;
+ }
+
+ @OnScheduled
+ public void setup(ProcessContext context) {
+ try {
+ if (resetState) {
+ context.getStateManager().clear(Scope.LOCAL);
+ resetState = false;
+ }
+ } catch (IOException ioe) {
+ throw new ProcessException(ioe);
+ }
+ }
+
+ @Override
+ public void onTrigger(ProcessContext context, ProcessSession session)
throws ProcessException {
+ final ComponentLog logger = getLogger();
+ final DBCPService dbcpService =
context.getProperty(DBCP_SERVICE).asControllerService(DBCPService.class);
+ final String catalog = context.getProperty(CATALOG).getValue();
+ final String schemaPattern =
context.getProperty(SCHEMA_PATTERN).getValue();
+ final String tableNamePattern =
context.getProperty(TABLE_NAME_PATTERN).getValue();
+ final String[] tableTypes =
context.getProperty(TABLE_TYPES).isSet()
+ ?
context.getProperty(TABLE_TYPES).getValue().split("\\s*,\\s*")
+ : null;
+ final boolean includeCount =
context.getProperty(INCLUDE_COUNT).asBoolean();
+
+ final StateManager stateManager = context.getStateManager();
+ final StateMap stateMap;
+ final Map<String, String> stateMapProperties;
+ try {
+ stateMap = stateManager.getState(Scope.LOCAL);
+ stateMapProperties = new HashMap<>(stateMap.toMap());
+ } catch (IOException ioe) {
+ throw new ProcessException(ioe);
+ }
+
+ try (final Connection con = dbcpService.getConnection()) {
+
+ DatabaseMetaData dbMetaData = con.getMetaData();
+ ResultSet rs = dbMetaData.getTables(catalog, schemaPattern,
tableNamePattern, tableTypes);
+ while (rs.next()) {
+ final String tableCatalog = rs.getString(1);
+ final String tableSchema = rs.getString(2);
+ final String tableName = rs.getString(3);
+ final String tableType = rs.getString(4);
+ final String tableRemarks = rs.getString(5);
+
+ // Build fully-qualified name
+ String fqn = Stream.of(tableCatalog, tableSchema,
tableName)
+ .filter(segment -> !StringUtils.isEmpty(segment))
+ .collect(Collectors.joining("."));
+
+ String fqTableName = stateMap.get(fqn);
+ if (fqTableName == null) {
+ FlowFile flowFile = session.create();
+ logger.info("Found {}: {}", new Object[]{tableType,
fqn});
+ if (includeCount) {
+ try (Statement st = con.createStatement()) {
+ final String countQuery = "SELECT COUNT(1)
FROM " + fqn;
+
+ logger.debug("Executing query: {}", new
Object[]{countQuery});
+ ResultSet countResult =
st.executeQuery(countQuery);
+ if (countResult.next()) {
+ flowFile = session.putAttribute(flowFile,
DB_TABLE_COUNT, Long.toString(countResult.getLong(1)));
+ }
+ } catch (SQLException se) {
+ logger.error("Couldn't get row count for {}",
new Object[]{fqn});
+ session.remove(flowFile);
--- End diff --
It's a data generator, so not sure what counts as data loss. I could add a
"failure" relationship but I didn't see any precedence for transferring
newly-created flowfiles.
If you mean that an error getting the count shouldn't prevent the flow file
(minus the count) from being transferred, then yeah I can make that change.
Just wasn't sure from a UX perspective if they want a count and can't get one,
should the flow file be transferred?
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
