├── .gitignore ├── LICENSE ├── README.md ├── project.clj └── src └── jvm └── cascading └── dbmigrate ├── hadoop ├── DBConfiguration.java ├── DBInputFormat.java └── TupleWrapper.java └── tap └── DBMigrateTap.java /.gitignore: -------------------------------------------------------------------------------- 1 | _deps 2 | build 3 | target 4 | out 5 | lib 6 | pom.xml 7 | # use glob syntax. 8 | syntax: glob 9 | *.class 10 | *.jar 11 | *~ 12 | .DS_Store 13 | *.#* 14 | *#* 15 | *.classpath 16 | *.project 17 | *.settings 18 | *.dot 19 | .cake/ 20 | .lein-failures 21 | .lein-deps-sum 22 | doc 23 | *.ipr 24 | *.iws 25 | *.iml 26 | .idea 27 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright [yyyy] [name of copyright owner] 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | 203 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | cascading-dbmigrate 2 | =================== 3 | 4 | cascading-dbmigrate makes it easy to run Cascading flows on sql tables with a 5 | primary key of an int or a long. We use it at BackType to migrate data from our 6 | databases to HDFS. 7 | 8 | Cascading-DBMigrate is available [on Clojars](http://clojars.org/backtype/cascading-dbmigrate). 9 | 10 | Usage 11 | ----- 12 | 13 | To read data from a database in a Cascading flow, use DBMigrateTap. 14 | DBMigrateTap's constructor has the following signature: 15 | 16 | DBMigrateTap( 17 | int numChunks, // The number of splits to create of the database. 18 | // This will correspond to the number of mappers 19 | // created to read the database. 20 | String dbDriver, // For example, "com.mysql.jdbc.Driver" 21 | String dbUrl, // For example, "jdbc:mysql://localhost:3306/mydb" 22 | String username, // Username to connect to your database. 23 | String pwd, // Password to connect to your database. 24 | String tableName, // The table to read during the flow. 25 | String pkColumn, // The name of the primary key column of the table. 26 | String[] columnNames, // The names of the columns to read into the flow. 27 | Options ops // Optional, can provide min/max values to read. 28 | ) 29 | 30 | The tap will emit tuples containing one field for each column read, the field 31 | names being the column names. 32 | 33 | Examples 34 | -------- 35 | 36 | ### Cascalog 37 | 38 | ```clojure 39 | (defn db-range [min max] 40 | (let [opts (new cascading.dbmigrate.tap.DBMigrateTap$Options)] 41 | (set! (. opts :minId) min)) 42 | (set! (. opts :maxId) max)) 43 | opts)) 44 | 45 | (defn db-tap [table] 46 | (cascading.dbmigrate.tap.DBMigrateTap. 47 | 1 48 | "com.mysql.jdbc.Driver" 49 | "jdbc:mysql://localhost:3306/mydb" 50 | "root" 51 | "" 52 | table 53 | "id" 54 | (into-array ["id" "name"]) 55 | (db-range 1 100))) ;; Only load first 100 records 56 | 57 | 58 | (?<- (stdout) 59 | [?id ?name] 60 | ((db-tap "users") ?id ?name)) 61 | ``` 62 | 63 | Building 64 | -------- 65 | 66 | To build cascading-dbmigrate, follow these instructions: 67 | 68 | 1. Set `HADOOP_HOME` environment variable to the root directory of your hadoop distribution. 69 | 2. Set `CASCADING_HOME` environment variable to the root directory of your cascading distribution. 70 | 3. `ant jar` 71 | 72 | This will produce a single jar called `cascading_dbmigrate.jar` in the `build/` 73 | directory. 74 | 75 | 76 | Thanks to Chris Wensel for his help in developing this project. 77 | 78 | -------------------------------------------------------------------------------- /project.clj: -------------------------------------------------------------------------------- 1 | (defproject backtype/cascading-dbmigrate "1.1.0" 2 | :source-path "src/clj" 3 | :java-source-path "src/jvm" 4 | :javac-options {:debug "true" :fork "true"} 5 | :repositories {"conjars" "http://conjars.org/repo/"} 6 | :dependencies [[cascading/cascading-core "1.2.4" 7 | :exclusions [org.codehaus.janino/janino 8 | thirdparty/jgrapht-jdk1.6 9 | riffle/riffle]] 10 | [thirdparty/jgrapht-jdk1.6 "0.8.1"]] 11 | :dev-dependencies [[org.apache.hadoop/hadoop-core "0.20.2-dev"]]) 12 | -------------------------------------------------------------------------------- /src/jvm/cascading/dbmigrate/hadoop/DBConfiguration.java: -------------------------------------------------------------------------------- 1 | /** 2 | Copyright 2010 BackType 3 | 4 | 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. 5 | */ 6 | 7 | package cascading.dbmigrate.hadoop; 8 | 9 | import org.apache.hadoop.mapred.JobConf; 10 | 11 | import java.io.IOException; 12 | import java.sql.Connection; 13 | import java.sql.DriverManager; 14 | import java.sql.SQLException; 15 | 16 | public class DBConfiguration { 17 | 18 | public static final String DRIVER_CLASS_PROPERTY = "mapred.jdbc.driver.class"; 19 | public static final String URL_PROPERTY = "mapred.jdbc.url"; 20 | public static final String USERNAME_PROPERTY = "mapred.jdbc.username"; 21 | public static final String PASSWORD_PROPERTY = "mapred.jdbc.password"; 22 | public static final String INPUT_TABLE_NAME_PROPERTY = "mapred.jdbc.input.table.name"; 23 | public static final String INPUT_COLUMN_NAMES_PROPERTY = "mapred.jdbc.input.column.names"; 24 | public static final String PRIMARY_KEY_COLUMN = "mapred.jdbc.primary.key.name"; 25 | public static final String NUM_CHUNKS = "mapred.jdbc.num.chunks"; 26 | public static final String MIN_ID = "dbmigrate.min.id"; 27 | public static final String MAX_ID = "dbmigrate.max.id"; 28 | 29 | public void configureDB(String driverClass, String dbUrl, String userName, String passwd) { 30 | job.set(DRIVER_CLASS_PROPERTY, driverClass); 31 | job.set(URL_PROPERTY, dbUrl); 32 | 33 | if (userName != null) { 34 | job.set(USERNAME_PROPERTY, userName); 35 | } 36 | 37 | if (passwd != null) { 38 | job.set(PASSWORD_PROPERTY, passwd); 39 | } 40 | } 41 | 42 | public void configureDB(String driverClass, String dbUrl) { 43 | configureDB(driverClass, dbUrl, null, null); 44 | } 45 | 46 | public JobConf job; 47 | 48 | public DBConfiguration(JobConf job) { 49 | this.job = job; 50 | } 51 | 52 | public Connection getConnection() throws IOException { 53 | try { 54 | Class.forName(job.get(DBConfiguration.DRIVER_CLASS_PROPERTY)); 55 | } catch (ClassNotFoundException exception) { 56 | throw new IOException("unable to load conection driver", exception); 57 | } 58 | Connection ret; 59 | 60 | try { 61 | if (job.get(DBConfiguration.USERNAME_PROPERTY) == null) { 62 | ret = DriverManager.getConnection(job.get(DBConfiguration.URL_PROPERTY)); 63 | } else { 64 | ret = DriverManager.getConnection(job.get(DBConfiguration.URL_PROPERTY), job 65 | .get(DBConfiguration.USERNAME_PROPERTY), job 66 | .get(DBConfiguration.PASSWORD_PROPERTY)); 67 | } 68 | return ret; 69 | } catch (SQLException exception) { 70 | throw new IOException("unable to create connection", exception); 71 | } 72 | } 73 | 74 | public String getInputTableName() { 75 | return job.get(DBConfiguration.INPUT_TABLE_NAME_PROPERTY); 76 | } 77 | 78 | public void setInputTableName(String tableName) { 79 | job.set(DBConfiguration.INPUT_TABLE_NAME_PROPERTY, tableName); 80 | } 81 | 82 | public String[] getInputColumnNames() { 83 | return job.getStrings(DBConfiguration.INPUT_COLUMN_NAMES_PROPERTY); 84 | } 85 | 86 | public void setInputColumnNames(String... fieldNames) { 87 | job.setStrings(DBConfiguration.INPUT_COLUMN_NAMES_PROPERTY, fieldNames); 88 | } 89 | 90 | public String getPrimaryKeyColumn() { 91 | return job.get(PRIMARY_KEY_COLUMN); 92 | } 93 | 94 | public void setPrimaryKeyColumn(String key) { 95 | job.set(PRIMARY_KEY_COLUMN, key); 96 | } 97 | 98 | public void setNumChunks(int numChunks) { 99 | job.setInt(NUM_CHUNKS, numChunks); 100 | } 101 | 102 | public int getNumChunks() { 103 | return job.getInt(NUM_CHUNKS, 10); 104 | } 105 | 106 | public void setMinId(long id) { 107 | job.setLong(MIN_ID, id); 108 | } 109 | 110 | public Long getMinId() { 111 | if (job.get(MIN_ID) == null) { return null; } 112 | return job.getLong(MIN_ID, -1); 113 | } 114 | 115 | public void setMaxId(long id) { 116 | job.setLong(MAX_ID, id); 117 | } 118 | 119 | public Long getMaxId() { 120 | if (job.get(MAX_ID) == null) { return null; } 121 | return job.getLong(MAX_ID, -1); 122 | } 123 | } 124 | 125 | -------------------------------------------------------------------------------- /src/jvm/cascading/dbmigrate/hadoop/DBInputFormat.java: -------------------------------------------------------------------------------- 1 | /** 2 | Copyright 2010 BackType 3 | 4 | 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. 5 | */ 6 | package cascading.dbmigrate.hadoop; 7 | 8 | import cascading.tuple.Tuple; 9 | import org.apache.hadoop.io.BytesWritable; 10 | import org.apache.hadoop.io.LongWritable; 11 | import org.apache.hadoop.io.WritableUtils; 12 | import org.apache.hadoop.mapred.*; 13 | import org.slf4j.Logger; 14 | import org.slf4j.LoggerFactory; 15 | 16 | import java.io.DataInput; 17 | import java.io.DataOutput; 18 | import java.io.IOException; 19 | import java.math.BigDecimal; 20 | import java.math.BigInteger; 21 | import java.sql.*; 22 | 23 | public class DBInputFormat implements InputFormat { 24 | 25 | private static final Logger LOG = LoggerFactory.getLogger(DBInputFormat.class); 26 | 27 | public static class DBRecordReader implements RecordReader { 28 | 29 | private ResultSet results; 30 | private Statement statement; 31 | private Connection connection; 32 | private DBInputSplit split; 33 | private long pos = 0; 34 | 35 | protected DBRecordReader(DBInputSplit split, JobConf job) throws IOException { 36 | try { 37 | this.split = split; 38 | DBConfiguration conf = new DBConfiguration(job); 39 | connection = conf.getConnection(); 40 | 41 | statement = connection 42 | .createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY); 43 | 44 | //statement.setFetchSize(Integer.MIN_VALUE); 45 | String query = getSelectQuery(conf, split); 46 | LOG.info("Running query: " + query); 47 | try { 48 | results = statement.executeQuery(query); 49 | } catch (SQLException exception) { 50 | LOG.error("unable to execute select query: " + query, exception); 51 | throw new IOException("unable to execute select query: " + query, exception); 52 | } 53 | } catch (SQLException e) { 54 | throw new RuntimeException(e); 55 | } 56 | } 57 | 58 | public static String join(T[] arr, String sep) { 59 | String ret = ""; 60 | for (int i = 0; i < arr.length; i++) { 61 | ret = ret + arr[i]; 62 | if (i < arr.length - 1) { 63 | ret = ret + sep; 64 | } 65 | } 66 | return ret; 67 | } 68 | 69 | protected String getSelectQuery(DBConfiguration conf, DBInputSplit split) { 70 | StringBuilder query = new StringBuilder(); 71 | query.append("SELECT "); 72 | query.append(join(conf.getInputColumnNames(), ",")); 73 | query.append(" FROM "); 74 | query.append(conf.getInputTableName()); 75 | query.append(" WHERE "); 76 | query.append(split.primaryKeyColumn + ">=" + split.startId); 77 | query.append(" AND "); 78 | query.append(split.primaryKeyColumn + "<" + split.endId); 79 | return query.toString(); 80 | } 81 | 82 | public void close() throws IOException { 83 | try { 84 | results.close(); 85 | statement.close(); 86 | connection.close(); 87 | } catch (SQLException exception) { 88 | throw new IOException("unable to commit and close", exception); 89 | } 90 | } 91 | 92 | /** {@inheritDoc} */ 93 | public LongWritable createKey() { 94 | return new LongWritable(); 95 | } 96 | 97 | /** {@inheritDoc} */ 98 | public TupleWrapper createValue() { 99 | return new TupleWrapper(); 100 | } 101 | 102 | /** {@inheritDoc} */ 103 | public long getPos() throws IOException { 104 | return pos; 105 | } 106 | 107 | /** {@inheritDoc} */ 108 | public float getProgress() throws IOException { 109 | return (pos / (float) split.getLength()); 110 | } 111 | 112 | /** {@inheritDoc} */ 113 | public boolean next(LongWritable key, TupleWrapper value) throws IOException { 114 | try { 115 | if (!results.next()) { 116 | return false; 117 | } 118 | key.set(pos + split.startId); 119 | 120 | value.tuple = new Tuple(); 121 | 122 | for (int i = 0; i < results.getMetaData().getColumnCount(); i++) { 123 | Object o = results.getObject(i + 1); 124 | if (o instanceof byte[]) { 125 | o = new BytesWritable((byte[]) o); 126 | } else if (o instanceof BigInteger) { 127 | o = ((BigInteger) o).longValue(); 128 | } else if (o instanceof BigDecimal) { 129 | o = ((BigDecimal) o).doubleValue(); 130 | } 131 | try { 132 | value.tuple.add(o); 133 | } catch (Throwable t) { 134 | LOG.info("WTF: " + o.toString() + o.getClass().toString()); 135 | throw new RuntimeException(t); 136 | } 137 | } 138 | pos++; 139 | } catch (SQLException exception) { 140 | throw new IOException("unable to get next value", exception); 141 | } 142 | return true; 143 | } 144 | } 145 | 146 | protected static class DBInputSplit implements InputSplit { 147 | 148 | public long endId = 0; 149 | public long startId = 0; 150 | public String primaryKeyColumn; 151 | 152 | public DBInputSplit() { 153 | } 154 | 155 | public DBInputSplit(long start, long end, String primaryKeyColumn) { 156 | startId = start; 157 | endId = end; 158 | this.primaryKeyColumn = primaryKeyColumn; 159 | } 160 | 161 | public String[] getLocations() throws IOException { 162 | return new String[]{}; 163 | } 164 | 165 | public long getLength() throws IOException { 166 | return endId - startId; 167 | } 168 | 169 | public void readFields(DataInput input) throws IOException { 170 | startId = input.readLong(); 171 | endId = input.readLong(); 172 | primaryKeyColumn = WritableUtils.readString(input); 173 | } 174 | 175 | public void write(DataOutput output) throws IOException { 176 | output.writeLong(startId); 177 | output.writeLong(endId); 178 | WritableUtils.writeString(output, primaryKeyColumn); 179 | } 180 | } 181 | 182 | public RecordReader getRecordReader(InputSplit split, JobConf job, 183 | Reporter reporter) throws IOException { 184 | return new DBRecordReader((DBInputSplit) split, job); 185 | } 186 | 187 | private long getMaxId(DBConfiguration conf, Connection conn, String tableName, String col) { 188 | if (conf.getMaxId() != null) { 189 | return conf.getMaxId(); 190 | } 191 | try { 192 | PreparedStatement s = 193 | conn.prepareStatement("SELECT MAX(" + col + ") FROM " + tableName); 194 | ResultSet rs = s.executeQuery(); 195 | rs.next(); 196 | long ret = rs.getLong(1); 197 | rs.close(); 198 | s.close(); 199 | return ret; 200 | } catch (SQLException e) { 201 | throw new RuntimeException(e); 202 | } 203 | } 204 | 205 | private long getMinId(DBConfiguration conf, Connection conn, String tableName, String col) { 206 | if (conf.getMinId() != null) { 207 | return conf.getMinId(); 208 | } 209 | try { 210 | PreparedStatement s = 211 | conn.prepareStatement("SELECT MIN(" + col + ") FROM " + tableName); 212 | ResultSet rs = s.executeQuery(); 213 | rs.next(); 214 | long ret = rs.getLong(1); 215 | rs.close(); 216 | s.close(); 217 | return ret; 218 | } catch (SQLException e) { 219 | throw new RuntimeException(e); 220 | } 221 | } 222 | 223 | public InputSplit[] getSplits(JobConf job, int ignored) throws IOException { 224 | try { 225 | DBConfiguration conf = new DBConfiguration(job); 226 | int chunks = conf.getNumChunks(); 227 | Connection conn = conf.getConnection(); 228 | String primarykeycolumn = conf.getPrimaryKeyColumn(); 229 | long maxId = getMaxId(conf, conn, conf.getInputTableName(), conf.getPrimaryKeyColumn()); 230 | long minId = getMinId(conf, conn, conf.getInputTableName(), conf.getPrimaryKeyColumn()); 231 | long chunkSize = (maxId - minId + 1) / chunks + 1; 232 | chunks = (int) ((maxId - minId + 1) / chunkSize) + 1; 233 | InputSplit[] ret = new InputSplit[chunks]; 234 | 235 | long currId = minId; 236 | for (int i = 0; i < chunks; i++) { 237 | long start = currId; 238 | currId += chunkSize; 239 | ret[i] = new DBInputSplit(start, Math.min(currId, maxId + 1), primarykeycolumn); 240 | } 241 | 242 | conn.close(); 243 | return ret; 244 | } catch (SQLException e) { 245 | throw new RuntimeException(e); 246 | } 247 | } 248 | 249 | public static void setInput(JobConf job, int numChunks, String databaseDriver, String username, 250 | String pwd, String dburl, String tableName, String pkColumn, Long minId, Long maxId, 251 | String... columnNames) { 252 | job.setInputFormat(DBInputFormat.class); 253 | 254 | DBConfiguration dbConf = new DBConfiguration(job); 255 | dbConf.configureDB(databaseDriver, dburl, username, pwd); 256 | if (minId != null) { 257 | dbConf.setMinId(minId.longValue()); 258 | } 259 | if (maxId != null) { 260 | dbConf.setMaxId(maxId.longValue()); 261 | } 262 | dbConf.setInputTableName(tableName); 263 | dbConf.setInputColumnNames(columnNames); 264 | dbConf.setPrimaryKeyColumn(pkColumn); 265 | dbConf.setNumChunks(numChunks); 266 | } 267 | } 268 | -------------------------------------------------------------------------------- /src/jvm/cascading/dbmigrate/hadoop/TupleWrapper.java: -------------------------------------------------------------------------------- 1 | /** 2 | Copyright 2010 BackType 3 | 4 | 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. 5 | */ 6 | package cascading.dbmigrate.hadoop; 7 | 8 | import cascading.tuple.Tuple; 9 | 10 | 11 | public class TupleWrapper { 12 | public Tuple tuple; 13 | } 14 | -------------------------------------------------------------------------------- /src/jvm/cascading/dbmigrate/tap/DBMigrateTap.java: -------------------------------------------------------------------------------- 1 | /** 2 | Copyright 2010 BackType 3 | 4 | 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. 5 | */ 6 | package cascading.dbmigrate.tap; 7 | 8 | import cascading.dbmigrate.hadoop.DBInputFormat; 9 | import cascading.dbmigrate.hadoop.TupleWrapper; 10 | import cascading.scheme.Scheme; 11 | import cascading.tap.Tap; 12 | import cascading.tap.hadoop.TapIterator; 13 | import cascading.tuple.Fields; 14 | import cascading.tuple.Tuple; 15 | import cascading.tuple.TupleEntry; 16 | import cascading.tuple.TupleEntryCollector; 17 | import cascading.tuple.TupleEntryIterator; 18 | import java.io.IOException; 19 | import org.apache.hadoop.fs.Path; 20 | import org.apache.hadoop.mapred.FileInputFormat; 21 | import org.apache.hadoop.mapred.JobConf; 22 | import org.apache.hadoop.mapred.OutputCollector; 23 | import java.io.Serializable; 24 | 25 | 26 | public class DBMigrateTap extends Tap { 27 | public static class Options implements Serializable { 28 | public Long minId = null; 29 | public Long maxId = null; 30 | } 31 | 32 | public class DBMigrateScheme extends Scheme { 33 | String dbDriver; 34 | String dbUrl; 35 | String username; 36 | String pwd; 37 | String tableName; 38 | String pkColumn; 39 | String[] columnNames; 40 | int numChunks; 41 | Options options; 42 | 43 | public DBMigrateScheme(int numChunks, String dbDriver, String dbUrl, String username, String pwd, String tableName, String pkColumn, String[] columnNames, Options options) { 44 | super(new Fields(columnNames)); 45 | this.dbDriver = dbDriver; 46 | this.dbUrl = dbUrl; 47 | this.username = username; 48 | this.pwd = pwd; 49 | this.tableName = tableName; 50 | this.pkColumn = pkColumn; 51 | this.columnNames = columnNames; 52 | this.numChunks = numChunks; 53 | this.options = options; 54 | } 55 | 56 | @Override 57 | public void sourceInit(Tap tap, JobConf jc) throws IOException { 58 | // a hack for MultiInputFormat to see that there is a child format 59 | FileInputFormat.setInputPaths( jc, getPath() ); 60 | 61 | DBInputFormat.setInput(jc, numChunks, dbDriver, username, pwd, dbUrl, tableName, pkColumn, options.minId, options.maxId, columnNames); 62 | } 63 | 64 | @Override 65 | public void sinkInit(Tap tap, JobConf jc) throws IOException { 66 | throw new UnsupportedOperationException("Cannot be used as a sink"); 67 | } 68 | 69 | @Override 70 | public Tuple source(Object key, Object val) { 71 | return ((TupleWrapper) val).tuple; 72 | } 73 | 74 | @Override 75 | public void sink(TupleEntry te, OutputCollector oc) throws IOException { 76 | throw new UnsupportedOperationException("Cannot be used as a sink."); 77 | } 78 | } 79 | 80 | String connectionUrl; 81 | 82 | public DBMigrateTap(int numChunks, String dbDriver, String dbUrl, String username, String pwd, String tableName, String pkColumn, String[] columnNames) { 83 | this(numChunks, dbDriver, dbUrl, username, pwd, tableName, pkColumn, columnNames, new Options()); 84 | } 85 | 86 | public DBMigrateTap(int numChunks, String dbDriver, String dbUrl, String username, String pwd, String tableName, String pkColumn, String[] columnNames, Options options) { 87 | setScheme(new DBMigrateScheme(numChunks, dbDriver, dbUrl, username, pwd, tableName, pkColumn, columnNames, options)); 88 | this.connectionUrl = dbUrl; 89 | } 90 | 91 | @Override 92 | public Path getPath() { 93 | return new Path( "jdbc:/" + connectionUrl.replaceAll( ":", "_" ) ); 94 | } 95 | 96 | @Override 97 | public TupleEntryIterator openForRead(JobConf conf) throws IOException { 98 | return new TupleEntryIterator(getSourceFields(), new TapIterator(this, conf)); 99 | } 100 | 101 | @Override 102 | public TupleEntryCollector openForWrite(JobConf jc) throws IOException { 103 | throw new UnsupportedOperationException("Not supported."); 104 | } 105 | 106 | @Override 107 | public boolean makeDirs(JobConf jc) throws IOException { 108 | return true; 109 | } 110 | 111 | @Override 112 | public boolean deletePath(JobConf jc) throws IOException { 113 | return false; 114 | } 115 | 116 | @Override 117 | public boolean pathExists(JobConf jc) throws IOException { 118 | return true; 119 | } 120 | 121 | @Override 122 | public long getPathModified(JobConf jc) throws IOException { 123 | return System.currentTimeMillis(); 124 | } 125 | 126 | } 127 | --------------------------------------------------------------------------------