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io.cdap.plugin.Decoder Maven / Gradle / Ivy
/*
* Copyright © 2015-2019 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 io.cdap.plugin;
import com.google.common.base.Strings;
import io.cdap.cdap.api.annotation.Description;
import io.cdap.cdap.api.annotation.Name;
import io.cdap.cdap.api.annotation.Plugin;
import io.cdap.cdap.api.data.format.StructuredRecord;
import io.cdap.cdap.api.data.schema.Schema;
import io.cdap.cdap.api.data.schema.Schema.Field;
import io.cdap.cdap.api.plugin.PluginConfig;
import io.cdap.cdap.etl.api.Emitter;
import io.cdap.cdap.etl.api.FailureCollector;
import io.cdap.cdap.etl.api.PipelineConfigurer;
import io.cdap.cdap.etl.api.StageConfigurer;
import io.cdap.cdap.etl.api.StageSubmitterContext;
import io.cdap.cdap.etl.api.Transform;
import io.cdap.cdap.etl.api.TransformContext;
import io.cdap.cdap.etl.api.lineage.field.FieldOperation;
import io.cdap.plugin.common.TransformLineageRecorderUtils;
import org.apache.commons.codec.binary.Base32;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.stream.Collectors;
import javax.annotation.Nullable;
/**
* 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 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;
}
@Override
public void configurePipeline(PipelineConfigurer pipelineConfigurer) throws IllegalArgumentException {
super.configurePipeline(pipelineConfigurer);
StageConfigurer stageConfigurer = pipelineConfigurer.getStageConfigurer();
FailureCollector collector = stageConfigurer.getFailureCollector();
parseConfiguration(config.decode, collector);
validateInputSchema(stageConfigurer.getInputSchema(), collector);
Schema outputSchema = config.getSchema(collector);
if (outputSchema != null) {
for (String fieldName : decodeMap.keySet()) {
if (outputSchema.getField(fieldName) == null) {
collector.addFailure(String.format("Field '%s' must be in output schema.", fieldName), null)
.withConfigElement(Config.NAME_DECODE, fieldName + Config.SEPARATOR + decodeMap.get(fieldName));
continue;
}
Field field = outputSchema.getField(fieldName);
Schema nonNullableSchema = field.getSchema().isNullable() ? field.getSchema().getNonNullable()
: field.getSchema();
if (nonNullableSchema.getType() != Schema.Type.BYTES && nonNullableSchema.getType() != Schema.Type.STRING
|| nonNullableSchema.getLogicalType() != null) {
collector.addFailure(String.format("Decode field '%s' is of invalid type '%s'.",
field.getName(), nonNullableSchema.getDisplayName()),
"Ensure the decode field is of type string or bytes.")
.withOutputSchemaField(field.getName())
.withConfigElement(Config.NAME_DECODE, fieldName + Config.SEPARATOR + decodeMap.get(fieldName));
}
}
}
stageConfigurer.setOutputSchema(outputSchema);
}
@Override
public void prepareRun(StageSubmitterContext context) throws Exception {
super.prepareRun(context);
parseConfiguration(config.decode, context.getFailureCollector());
// Initialize the required member maps and then: if a field is in input and output and decode, then
// set it to transform; if it's in input and output but not decode, ignore it; if it's in input and
// not output, drop it.
List inFields = TransformLineageRecorderUtils.getFields(context.getInputSchema());
List outFields = TransformLineageRecorderUtils.getFields(context.getOutputSchema());
List identityFields = outFields.stream()
.filter(field -> !decodeMap.containsKey(field) || decodeMap.get(field) == DecoderType.NONE)
.collect(Collectors.toList());
List processedFields = new ArrayList<>(outFields);
processedFields.removeAll(identityFields);
List droppedFields = new ArrayList<>(inFields);
droppedFields.removeAll(outFields);
List output = new ArrayList<>();
output.addAll(TransformLineageRecorderUtils.generateOneToOnes(processedFields, "decode",
"Decoded the input fields based on expected decoder."));
output.addAll(TransformLineageRecorderUtils.generateDrops(droppedFields));
output.addAll(TransformLineageRecorderUtils.generateOneToOnes(identityFields, "identity",
TransformLineageRecorderUtils.IDENTITY_TRANSFORM_DESCRIPTION));
context.record(output);
}
@Override
public void initialize(TransformContext context) throws Exception {
super.initialize(context);
FailureCollector collector = context.getFailureCollector();
parseConfiguration(config.decode, collector);
collector.getOrThrowException();
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());
}
private void parseConfiguration(String config, FailureCollector collector) {
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) {
collector.addFailure(String.format("Configuration '%s' is incorrectly formed.", mapping),
"Specify the configuration in the format :.")
.withConfigProperty(Config.NAME_DECODE);
continue;
}
String field = params[0];
String type = params[1].toUpperCase();
DecoderType eType = DecoderType.valueOf(type);
if (decodeMap.containsKey(field)) {
collector.addFailure(String.format("Field '%s' already has decoder set.", field),
"Ensure different fields are provided.")
.withConfigElement(Config.NAME_DECODE, mapping);
continue;
}
decodeMap.put(field, eType);
}
}
private void validateInputSchema(@Nullable Schema inputSchema, FailureCollector collector) {
if (inputSchema == null) {
return;
}
// 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
for (Field field : inputSchema.getFields()) {
if (decodeMap.containsKey(field.getName())) {
String fieldName = field.getName();
Schema nonNullableSchema = field.getSchema().isNullable() ? field.getSchema().getNonNullable() :
field.getSchema();
if (!nonNullableSchema.getType().equals(Schema.Type.BYTES) &&
!nonNullableSchema.getType().equals(Schema.Type.STRING) || nonNullableSchema.getLogicalType() != null) {
collector.addFailure(String.format("Input field '%s' is of unsupported type '%s'.",
field.getName(), nonNullableSchema.getDisplayName()),
"Supported input types are bytes and string.")
.withInputSchemaField(field.getName())
.withConfigElement(Config.NAME_DECODE, fieldName + Config.SEPARATOR + decodeMap.get(fieldName));
}
}
}
}
/**
* 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 {
private static final String NAME_DECODE = "decode";
private static final String NAME_SCHEMA = "schema";
private static final String SEPARATOR = ":";
@Name(NAME_DECODE)
@Description("Specify the field and decode type combination. " +
"Format is :[,:]*")
private final String decode;
@Name(NAME_SCHEMA)
@Description("Specifies the output schema")
private final String schema;
public Config(String decode, String schema) {
this.decode = decode;
this.schema = schema;
}
@Nullable
private Schema getSchema(FailureCollector collector) {
try {
return Strings.isNullOrEmpty(schema) ? null : Schema.parseJson(schema);
} catch (IOException e) {
collector.addFailure("Invalid schema : " + e.getMessage(), null).withConfigProperty(NAME_SCHEMA);
}
throw collector.getOrThrowException();
}
}
}
