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co.cask.hydrator.plugin.Decompressor Maven / Gradle / Ivy
/*
* Copyright © 2015 Cask Data, Inc.
*
* 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 co.cask.hydrator.plugin;
import co.cask.cdap.api.annotation.Description;
import co.cask.cdap.api.annotation.Name;
import co.cask.cdap.api.annotation.Plugin;
import co.cask.cdap.api.data.format.StructuredRecord;
import co.cask.cdap.api.data.schema.Schema;
import co.cask.cdap.api.data.schema.Schema.Field;
import co.cask.cdap.api.plugin.PluginConfig;
import co.cask.cdap.etl.api.Emitter;
import co.cask.cdap.etl.api.PipelineConfigurer;
import co.cask.cdap.etl.api.Transform;
import co.cask.cdap.etl.api.TransformContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xerial.snappy.Snappy;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.zip.GZIPInputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
/**
* Decompreses the configured fields using the algorithms specified.
*/
@Plugin(type = "transform")
@Name("Decompressor")
@Description("Decompresses configured fields using the algorithms specified.")
public final class Decompressor extends Transform {
private static final Logger LOG = LoggerFactory.getLogger(Decompressor.class);
private final Config config;
// Output Schema associated with transform output.
private Schema outSchema;
// Output Field name to type map
private Map outSchemaMap = new HashMap<>();
// Map of field to decompressor type.
private final Map deCompMap = new TreeMap<>();
// This is used only for tests, otherwise this is being injected by the ingestion framework.
public Decompressor(Config config) {
this.config = config;
}
private void parseConfiguration(String config) throws IllegalArgumentException {
String[] mappings = config.split(",");
for (String mapping : mappings) {
String[] params = mapping.split(":");
// If format is not right, then we throw an exception.
if (params.length < 2) {
throw new IllegalArgumentException("Configuration " + mapping + " is in-correctly formed. " +
"Format should be :");
}
String field = params[0];
String type = params[1].toUpperCase();
DecompressorType cType = DecompressorType.valueOf(type);
if (deCompMap.containsKey(field)) {
throw new IllegalArgumentException("Field " + field + " already has decompressor set. Check the mapping.");
} else {
deCompMap.put(field, cType);
}
}
}
@Override
public void configurePipeline(PipelineConfigurer pipelineConfigurer) throws IllegalArgumentException {
super.configurePipeline(pipelineConfigurer);
parseConfiguration(config.decompressor);
// Check if schema specified is a valid schema or no.
try {
Schema outputSchema = Schema.parseJson(config.schema);
List outFields = outputSchema.getFields();
for (Field field : outFields) {
outSchemaMap.put(field.getName(), field.getSchema().getType());
}
pipelineConfigurer.getStageConfigurer().setOutputSchema(outputSchema);
} catch (IOException e) {
throw new IllegalArgumentException("Format of schema specified is invalid. Please check the format. " +
e.getMessage());
}
Schema inputSchema = pipelineConfigurer.getStageConfigurer().getInputSchema();
if (inputSchema != null) {
for (Schema.Field field : inputSchema.getFields()) {
if (outSchemaMap.containsKey(field.getName()) &&
deCompMap.containsKey(field.getName()) && deCompMap.get(field.getName()) != DecompressorType.NONE &&
!Schema.Type.BYTES.equals(field.getSchema().getType())) {
throw new IllegalArgumentException(
String.format("Decompression is selected for the input field %s, but the field is of type %s. " +
"Decompression is supported only for the type Bytes.",
field.getName(), field.getSchema().getType().toString()));
}
}
}
for (Map.Entry entry : deCompMap.entrySet()) {
if (!outSchemaMap.containsKey(entry.getKey())) {
throw new IllegalArgumentException("Field '" + entry.getKey() + "' specified to be decompresed is not " +
"present in the output schema. Please add field '" + entry.getKey() + "'" +
"to output schema or remove it from decompress");
}
if (outSchemaMap.get(entry.getKey()) != Schema.Type.BYTES &&
outSchemaMap.get(entry.getKey()) != Schema.Type.STRING) {
throw new IllegalArgumentException("Field '" + entry.getKey() + "' should be of type BYTES or STRING in " +
"output schema.");
}
}
}
@Override
public void initialize(TransformContext context) throws Exception {
super.initialize(context);
parseConfiguration(config.decompressor);
try {
outSchema = Schema.parseJson(config.schema);
List outFields = outSchema.getFields();
for (Field field : outFields) {
outSchemaMap.put(field.getName(), field.getSchema().getType());
}
} catch (IOException e) {
throw new IllegalArgumentException("Format of schema specified is invalid. Please check the format." +
e.getMessage());
}
}
@Override
public void transform(StructuredRecord in, Emitter emitter) throws Exception {
StructuredRecord.Builder builder = StructuredRecord.builder(outSchema);
Schema inSchema = in.getSchema();
List inFields = inSchema.getFields();
// Iterate through input fields. Check if field name is present
// in the fields that need to be decompressed, if it's not then write
// to output as it is.
for (Field field : inFields) {
String name = field.getName();
// Check if output schema also have the same field name. If it's not
// then continue.
if (!outSchemaMap.containsKey(name)) {
continue;
}
Schema.Type outFieldType = outSchemaMap.get(name);
// Check if the input field name is configured to be encoded. If the field is not
// present or is defined as none, then pass through the field as is.
if (!deCompMap.containsKey(name) || deCompMap.get(name) == DecompressorType.NONE) {
builder.set(name, in.get(name));
} else {
// Now, the input field should be of type byte[]
byte[] obj = new byte[0];
if (field.getSchema().getType() == Schema.Type.BYTES) {
obj = in.get(name);
} else {
LOG.error("Input field '" + name + "' should be of type BYTES to decompress. It is currently of type " +
"'" + field.getSchema().getType().toString() + "'");
break;
}
// Now, based on the encode type configured for the field - encode the byte[] of the
// value.
byte[] outValue = new byte[0];
DecompressorType type = deCompMap.get(name);
if (type == DecompressorType.SNAPPY) {
outValue = Snappy.uncompress(obj);
} else if (type == DecompressorType.ZIP) {
outValue = unzip(obj);
} else if (type == DecompressorType.GZIP) {
outValue = ungzip(obj);
}
// Depending on the output field type, either convert it to
// Bytes or to String.
if (outValue != null) {
if (outFieldType == Schema.Type.BYTES) {
builder.set(name, outValue);
} else if (outFieldType == Schema.Type.STRING) {
builder.set(name, new String(outValue, "UTF-8"));
}
}
}
}
emitter.emit(builder.build());
}
/**
* Decompresses using GZIP Algorithm.
*/
private byte[] ungzip(byte[] body) {
ByteArrayInputStream bytein = new ByteArrayInputStream(body);
try (GZIPInputStream gzin = new GZIPInputStream(bytein);
ByteArrayOutputStream byteout = new ByteArrayOutputStream()) {
int res = 0;
byte buf[] = new byte[1024];
while (res >= 0) {
res = gzin.read(buf, 0, buf.length);
if (res > 0) {
byteout.write(buf, 0, res);
}
}
byte uncompressed[] = byteout.toByteArray();
return uncompressed;
} catch (IOException e) {
// Most of operations here are in memory. So, we shouldn't get here.
// Logging here is not an option.
}
return null;
}
/**
* Decompresses using ZIP Algorithm.
*/
private byte[] unzip(byte[] body) {
ZipEntry ze;
byte buf[] = new byte[1024];
try (ByteArrayOutputStream bao = new ByteArrayOutputStream();
ByteArrayInputStream bytein = new ByteArrayInputStream(body);
ZipInputStream zis = new ZipInputStream(bytein)) {
while ((ze = zis.getNextEntry()) != null) {
int l = 0;
while ((l = zis.read(buf)) > 0) {
bao.write(buf, 0, l);
}
}
return bao.toByteArray();
} catch (IOException e) {
// Most of operations here are in memory. So, we shouldn't get here.
// Logging here is not an option.
}
return null;
}
/**
* Enum specifying the decompressor type.
*/
private enum DecompressorType {
SNAPPY("SNAPPY"),
ZIP("ZIP"),
GZIP("GZIP"),
NONE("NONE");
private String type;
DecompressorType(String type) {
this.type = type;
}
String getType() {
return type;
}
}
/**
* Decompressor Plugin configuration.
*/
public static class Config extends PluginConfig {
@Name("decompressor")
@Description("Specify the field and decompression type combination. " +
"Format is :[,:]*")
private final String decompressor;
@Name("schema")
@Description("Specifies the output schema")
private final String schema;
public Config(String decompressor, String schema) {
this.decompressor = decompressor;
this.schema = schema;
}
}
}
