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org.apache.hadoop.hive.serde2.avro.AvroSerdeUtils Maven / Gradle / Ivy

/*
 * 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.
 */
package org.apache.hadoop.hive.serde2.avro;


import org.apache.avro.Schema;
import com.facebook.presto.hive.$internal.org.slf4j.Logger;
import com.facebook.presto.hive.$internal.org.slf4j.LoggerFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.common.type.HiveDecimal;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.serde.serdeConstants;
import org.apache.hadoop.hive.serde2.SerDeUtils;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoUtils;
import org.apache.hadoop.mapred.JobConf;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.Properties;

/**
 * Utilities useful only to the AvroSerde itself.  Not mean to be used by
 * end-users but public for interop to the ql package.
 */
public class AvroSerdeUtils {
    private static final Logger LOG = LoggerFactory.getLogger(AvroSerdeUtils.class);

    /**
     * Enum container for all avro table properties.
     * If introducing a new avro-specific table property,
     * add it here. Putting them in an enum rather than separate strings
     * allows them to be programmatically grouped and referenced together.
     */
    public static enum AvroTableProperties {
        SCHEMA_LITERAL("avro.schema.literal"),
        SCHEMA_URL("avro.schema.url"),
        SCHEMA_NAMESPACE("avro.schema.namespace"),
        SCHEMA_NAME("avro.schema.name"),
        SCHEMA_DOC("avro.schema.doc"),
        AVRO_SERDE_SCHEMA("avro.serde.schema"),
        SCHEMA_RETRIEVER("avro.schema.retriever");

        private final String propName;

        AvroTableProperties(String propName) {
            this.propName = propName;
        }

        public String getPropName(){
            return this.propName;
        }
    }

    // Following parameters slated for removal, prefer usage of enum above, that allows programmatic access.
    @Deprecated public static final String SCHEMA_LITERAL = "avro.schema.literal";
    @Deprecated public static final String SCHEMA_URL = "avro.schema.url";
    @Deprecated public static final String SCHEMA_NAMESPACE = "avro.schema.namespace";
    @Deprecated public static final String SCHEMA_NAME = "avro.schema.name";
    @Deprecated public static final String SCHEMA_DOC = "avro.schema.doc";
    @Deprecated public static final String AVRO_SERDE_SCHEMA = AvroTableProperties.AVRO_SERDE_SCHEMA.getPropName();
    @Deprecated public static final String SCHEMA_RETRIEVER = AvroTableProperties.SCHEMA_RETRIEVER.getPropName();

    public static final String SCHEMA_NONE = "none";
    public static final String EXCEPTION_MESSAGE = "Neither "
            + AvroTableProperties.SCHEMA_LITERAL.getPropName() + " nor "
            + AvroTableProperties.SCHEMA_URL.getPropName() + " specified, can't determine table schema";



    /**
     * Determine the schema to that's been provided for Avro serde work.
     * @param properties containing a key pointing to the schema, one way or another
     * @return schema to use while serdeing the avro file
     * @throws IOException if error while trying to read the schema from another location
     * @throws AvroSerdeException if unable to find a schema or pointer to it in the properties
     */
    public static Schema determineSchemaOrThrowException(Configuration conf, Properties properties)
            throws IOException, AvroSerdeException {
        String schemaString = properties.getProperty(AvroTableProperties.SCHEMA_LITERAL.getPropName());
        if(schemaString != null && !schemaString.equals(SCHEMA_NONE))
            return AvroSerdeUtils.getSchemaFor(schemaString);

        // Try pulling directly from URL
        schemaString = properties.getProperty(AvroTableProperties.SCHEMA_URL.getPropName());
        if (schemaString == null) {
            final String columnNameProperty = properties.getProperty(serdeConstants.LIST_COLUMNS);
            final String columnTypeProperty = properties.getProperty(serdeConstants.LIST_COLUMN_TYPES);
            final String columnCommentProperty = properties.getProperty(AvroSerDe.LIST_COLUMN_COMMENTS);
            if (columnNameProperty == null || columnNameProperty.isEmpty()
                    || columnTypeProperty == null || columnTypeProperty.isEmpty() ) {
                throw new AvroSerdeException(EXCEPTION_MESSAGE);
            }
            final String columnNameDelimiter = properties.containsKey(serdeConstants.COLUMN_NAME_DELIMITER) ? properties
                    .getProperty(serdeConstants.COLUMN_NAME_DELIMITER) : String.valueOf(SerDeUtils.COMMA);
            // Get column names and types
            List columnNames = Arrays.asList(columnNameProperty.split(columnNameDelimiter));
            List columnTypes = TypeInfoUtils.getTypeInfosFromTypeString(columnTypeProperty);

            Schema schema = AvroSerDe.getSchemaFromCols(properties, columnNames, columnTypes, columnCommentProperty);
            properties.setProperty(AvroTableProperties.SCHEMA_LITERAL.getPropName(), schema.toString());
            if (conf != null)
                conf.set(AvroTableProperties.AVRO_SERDE_SCHEMA.getPropName(), schema.toString(false));
            return schema;
        } else if(schemaString.equals(SCHEMA_NONE)) {
            throw new AvroSerdeException(EXCEPTION_MESSAGE);
        }

        try {
            Schema s = getSchemaFromFS(schemaString, conf);
            if (s == null) {
                //in case schema is not a file system
                return AvroSerdeUtils.getSchemaFor(new URL(schemaString));
            }
            return s;
        } catch (IOException ioe) {
            throw new AvroSerdeException("Unable to read schema from given path: " + schemaString, ioe);
        } catch (URISyntaxException urie) {
            throw new AvroSerdeException("Unable to read schema from given path: " + schemaString, urie);
        }
    }

    // Protected for testing and so we can pass in a conf for testing.
    protected static Schema getSchemaFromFS(String schemaFSUrl,
            Configuration conf) throws IOException, URISyntaxException {
        FSDataInputStream in = null;
        FileSystem fs = null;
        try {
            fs = FileSystem.get(new URI(schemaFSUrl), conf);
        } catch (IOException ioe) {
            //return null only if the file system in schema is not recognized
            if (LOG.isDebugEnabled()) {
                String msg = "Failed to open file system for uri " + schemaFSUrl + " assuming it is not a FileSystem url";
                LOG.debug(msg, ioe);
            }

            return null;
        }
        try {
            in = fs.open(new Path(schemaFSUrl));
            Schema s = AvroSerdeUtils.getSchemaFor(in);
            return s;
        } finally {
            if(in != null) in.close();
        }
    }

    /**
     * Determine if an Avro schema is of type Union[T, NULL].  Avro supports nullable
     * types via a union of type T and null.  This is a very common use case.
     * As such, we want to silently convert it to just T and allow the value to be null.
     *
     * When a Hive union type is used with AVRO, the schema type becomes
     * Union[NULL, T1, T2, ...]. The NULL in the union should be silently removed
     *
     * @return true if type represents Union[T, Null], false otherwise
     */
    public static boolean isNullableType(Schema schema) {
        if (!schema.getType().equals(Schema.Type.UNION)) {
            return false;
        }

        List itemSchemas = schema.getTypes();
        if (itemSchemas.size() < 2) {
            return false;
        }

        for (Schema itemSchema : itemSchemas) {
            if (Schema.Type.NULL.equals(itemSchema.getType())) {
                return true;
            }
        }

        // [null, null] not allowed, so this check is ok.
        return false;
    }

    /**
     * If the union schema is a nullable union, get the schema for the non-nullable type.
     * This method does no checking that the provided Schema is nullable. If the provided
     * union schema is non-nullable, it simply returns the union schema
     */
    public static Schema getOtherTypeFromNullableType(Schema unionSchema) {
        final List types = unionSchema.getTypes();
        if (types.size() == 2) { // most common scenario
            if (types.get(0).getType() == Schema.Type.NULL) {
                return types.get(1);
            }
            if (types.get(1).getType() == Schema.Type.NULL) {
                return types.get(0);
            }
            // not a nullable union
            return unionSchema;
        }

        final List itemSchemas = new ArrayList<>();
        for (Schema itemSchema : types) {
            if (!Schema.Type.NULL.equals(itemSchema.getType())) {
                itemSchemas.add(itemSchema);
            }
        }

        if (itemSchemas.size() > 1) {
            return Schema.createUnion(itemSchemas);
        } else {
            return itemSchemas.get(0);
        }
    }

    /**
     * Determine if we're being executed from within an MR job or as part
     * of a select * statement.  The signals for this varies between Hive versions.
     * @param job that contains things that are or are not set in a job
     * @return Are we in a job or not?
     */
    public static boolean insideMRJob(JobConf job) {
        return job != null
                && (HiveConf.getVar(job, HiveConf.ConfVars.PLAN) != null)
                && (!HiveConf.getVar(job, HiveConf.ConfVars.PLAN).isEmpty());
    }

    public static Buffer getBufferFromBytes(byte[] input) {
        ByteBuffer bb = ByteBuffer.wrap(input);
        return bb.rewind();
    }

    public static Buffer getBufferFromDecimal(HiveDecimal dec, int scale) {
        if (dec == null) {
            return null;
        }

        // NOTE: Previously, we did OldHiveDecimal.setScale(scale), called OldHiveDecimal
        //       unscaledValue().toByteArray().
        return AvroSerdeUtils.getBufferFromBytes(dec.bigIntegerBytesScaled(scale));
    }

    public static byte[] getBytesFromByteBuffer(ByteBuffer byteBuffer) {
        byteBuffer.rewind();
        byte[] result = new byte[byteBuffer.limit()];
        byteBuffer.get(result);
        return result;
    }

    public static HiveDecimal getHiveDecimalFromByteBuffer(ByteBuffer byteBuffer, int scale) {
        byte[] result = getBytesFromByteBuffer(byteBuffer);
        HiveDecimal dec = HiveDecimal.create(new BigInteger(result), scale);
        return dec;
    }

    public static Schema getSchemaFor(String str) {
        Schema.Parser parser = new Schema.Parser();
        Schema schema = parser.parse(str);
        return schema;
    }

    public static Schema getSchemaFor(File file) {
        Schema.Parser parser = new Schema.Parser();
        Schema schema;
        try {
            schema = parser.parse(file);
        } catch (IOException e) {
            throw new RuntimeException("Failed to parse Avro schema from " + file.getName(), e);
        }
        return schema;
    }

    public static Schema getSchemaFor(InputStream stream) {
        Schema.Parser parser = new Schema.Parser();
        Schema schema;
        try {
            schema = parser.parse(stream);
        } catch (IOException e) {
            throw new RuntimeException("Failed to parse Avro schema", e);
        }
        return schema;
    }

    public static Schema getSchemaFor(URL url) {
        InputStream in = null;
        try {
            in = url.openStream();
            return getSchemaFor(in);
        } catch (Exception e) {
            throw new RuntimeException("Failed to parse Avro schema", e);
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    // Ignore
                }
            }
        }
    }

    public static int getIntFromSchema(Schema schema, String name) {
        Object obj = schema.getObjectProp(name);
        if (obj instanceof String) {
            return Integer.parseInt((String) obj);
        } else if (obj instanceof Integer) {
            return (int) obj;
        } else {
            throw new IllegalArgumentException("Expect integer or string value from property " + name
                    + " but found type " + obj.getClass().getName());
        }
    }

    /**
     * Called on specific alter table events, removes schema url and schema literal from given tblproperties
     * After the change, HMS solely will be responsible for handling the schema
     *
     * @param conf
     * @param serializationLib
     * @param parameters
     */
    public static void handleAlterTableForAvro(HiveConf conf, String serializationLib, Map parameters) {
        if (AvroSerDe.class.getName().equals(serializationLib)) {
            String literalPropName = AvroTableProperties.SCHEMA_LITERAL.getPropName();
            String urlPropName = AvroTableProperties.SCHEMA_URL.getPropName();

            if (parameters.containsKey(literalPropName) || parameters.containsKey(urlPropName)) {
                throw new RuntimeException("Not allowed to alter schema of Avro stored table having external schema." +
                        " Consider removing "+AvroTableProperties.SCHEMA_LITERAL.getPropName() + " or " +
                        AvroTableProperties.SCHEMA_URL.getPropName() + " from table properties.");
            }
        }
    }
}




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