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co.cask.hydrator.plugin.Decoder 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.apache.commons.codec.binary.Base32;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
/**
* Decodes the input fields as BASE64, BASE32 or HEX.
* Please note that Encoder and Decoder might look the same right now, but in near future they will diverge.
*/
@Plugin(type = "transform")
@Name("Decoder")
@Description("Decodes the input field(s) using Base64, Base32, or Hex")
public final class Decoder extends Transform {
private static final Logger LOG = LoggerFactory.getLogger(Decoder.class);
private final Config config;
// Mapping of input field to decoder type.
private final Map decodeMap = new TreeMap<>();
// Decoder handlers.
private final Base64 base64Decoder = new Base64();
private final Base32 base32Decoder = new Base32();
private final Hex hexDecoder = new Hex();
// Output Field name to type map
private final Map outSchemaMap = new HashMap<>();
// Output Schema associated with transform output.
private Schema outSchema;
// This is used only for tests, otherwise this is being injected by the ingestion framework.
public Decoder(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 incorrectly formed. " +
"Format should be :");
}
String field = params[0];
String type = params[1].toUpperCase();
DecoderType eType = DecoderType.valueOf(type);
if (decodeMap.containsKey(field)) {
throw new IllegalArgumentException("Field " + field + " already has decoder set. Check the mapping.");
} else {
decodeMap.put(field, eType);
}
}
}
@Override
public void configurePipeline(PipelineConfigurer pipelineConfigurer) throws IllegalArgumentException {
super.configurePipeline(pipelineConfigurer);
parseConfiguration(config.decode);
Schema inputSchema = pipelineConfigurer.getStageConfigurer().getInputSchema();
// for the fields in input schema, if they are to be decoded (if present in decodeMap)
// make sure their type is either String or Bytes and throw exception otherwise
if (inputSchema != null) {
for (Schema.Field field : inputSchema.getFields()) {
if (decodeMap.containsKey(field.getName())) {
if (!field.getSchema().getType().equals(Schema.Type.BYTES) &&
!field.getSchema().getType().equals(Schema.Type.STRING)) {
throw new IllegalArgumentException(
String.format("Input field %s should be of type bytes or string. It is currently of type %s",
field.getName(), field.getSchema().getType().toString()));
}
}
}
}
// Check if schema specified is a valid schema or no.
try {
Schema outputSchema = Schema.parseJson(config.schema);
pipelineConfigurer.getStageConfigurer().setOutputSchema(outputSchema);
} catch (IOException e) {
throw new IllegalArgumentException("Format of schema specified is invalid. Please check the format.");
}
}
@Override
public void initialize(TransformContext context) throws Exception {
super.initialize(context);
parseConfiguration(config.decode);
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.");
}
}
@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 decoded, if it's not then write
// to output as it is.
for (Field field : inFields) {
String name = field.getName();
// Check if the output schema has the field, if it's not there
// then skip and move to processing the next field.
if (!outSchemaMap.containsKey(name)) {
continue;
}
Schema.Type outFieldType = outSchemaMap.get(name);
// Check if the input field name is configured to be decoded. If the field is not
// present or is defined as none, then pass through the field as is.
if (!decodeMap.containsKey(name) || decodeMap.get(name) == DecoderType.NONE) {
builder.set(name, in.get(name));
} else {
// Now, the input field could be of type String or byte[], so transform everything
// to byte[]
byte[] obj = new byte[0];
if (field.getSchema().getType() == Schema.Type.STRING) {
obj = ((String) in.get(name)).getBytes();
} else if (field.getSchema().getType() == Schema.Type.BYTES) {
obj = in.get(name);
}
// Now, based on the decode type configured for the field - decode the byte[] of the
// value.
byte[] outValue = new byte[0];
DecoderType type = decodeMap.get(name);
if (type == DecoderType.STRING_BASE32 || type == DecoderType.BASE32) {
outValue = base32Decoder.decode(obj);
} else if (type == DecoderType.STRING_BASE64 || type == DecoderType.BASE64) {
outValue = base64Decoder.decode(obj);
} else if (type == DecoderType.HEX) {
outValue = hexDecoder.decode(obj);
}
// Depending on the output field type, either convert it to
// Bytes or to String.
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());
}
/**
* Defines decoding types supported.
*/
private enum DecoderType {
BASE64("BASE64"),
BASE32("BASE32"),
STRING_BASE32("STRING_BASE32"),
STRING_BASE64("STRING_BASE64"),
HEX("HEX"),
NONE("NONE");
private String type;
DecoderType(String type) {
this.type = type;
}
String getType() {
return type;
}
}
/**
* Decoder Plugin config.
*/
public static class Config extends PluginConfig {
@Name("decode")
@Description("Specify the field and decode type combination. " +
"Format is :[,:]*")
private final String decode;
@Name("schema")
@Description("Specifies the output schema")
private final String schema;
public Config(String decode, String schema) {
this.decode = decode;
this.schema = schema;
}
}
}
