/**
* Licensed to Cloudera, Inc. under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Cloudera, Inc. licenses this file
* to you 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 com.cloudera.flume.conf;
import java.util.ArrayList;
import java.util.List;
import org.antlr.runtime.RecognitionException;
import org.antlr.runtime.tree.CommonTree;
import com.cloudera.flume.conf.FlumeBuilder.ASTNODE;
import com.cloudera.flume.master.FlumeNodeSpec;
import com.google.common.base.Preconditions;
/**
* This regenerates flume specs from parsed ASTs.
*
* The master node reads and parses commands. If they parse cleanly, this is
* used to regenerated the code as a string so it can be sent to the nodes.
*/
public class FlumeSpecGen {
static String genArg(CommonTree t) throws FlumeSpecException {
ASTNODE type = ASTNODE.valueOf(t.getText()); // convert to enum
switch (type) {
case HEX:
case DEC:
case BOOL:
case OCT:
case STRING:
case FLOAT:
return t.getChild(0).getText();
default:
throw new FlumeSpecException("Not a node of literal type: "
+ t.toStringTree());
}
}
static String genArgs(List<String> args, String pre, String delim, String post) {
StringBuilder b = new StringBuilder();
if (args.size() == 0)
return "";
b.append(pre + " ");
boolean first = true;
for (String arg : args) {
if (!first) {
b.append(delim + " ");
}
b.append(arg);
first = false;
}
b.append(" " + post);
return b.toString();
}
@SuppressWarnings("unchecked")
public static String genEventSource(CommonTree t) throws FlumeSpecException {
ASTNODE type = ASTNODE.valueOf(t.getText()); // convert to enum
switch (type) {
case SOURCE:
List<CommonTree> children = new ArrayList<CommonTree>(
(List<CommonTree>) t.getChildren());
String sourceType = children.remove(0).getText();
List<String> args = new ArrayList<String>();
for (CommonTree tr : children) {
args.add(genArg(tr));
}
return sourceType + genArgs(args, "(", ",", ")");
case MULTI:
List<CommonTree> elems = (List<CommonTree>) t.getChildren();
List<String> srcs = new ArrayList<String>();
for (CommonTree tr : elems) {
String src = genEventSource(tr);
srcs.add(src);
}
return genArgs(srcs, "[", ",", "]");
default:
throw new FlumeSpecException("bad parse tree! Expected source but got "
+ t.toStringTree());
}
}
@SuppressWarnings("unchecked")
public static String genEventSink(CommonTree t) throws FlumeSpecException {
if (t == null) {
throw new FlumeSpecException("Tree is null");
}
ASTNODE type = ASTNODE.valueOf(t.getText()); // convert to enum
switch (type) {
case SINK:
// copy so we don't modify original
List<CommonTree> children = (List<CommonTree>) new ArrayList<CommonTree>(
t.getChildren());
String sinkType = children.remove(0).getText();
List<String> args = new ArrayList<String>();
for (CommonTree tr : children) {
args.add(genArg(tr));
}
return sinkType + genArgs(args, "(", ",", ")");
case MULTI:
List<CommonTree> elems = (List<CommonTree>) t.getChildren();
List<String> snks = new ArrayList<String>();
for (CommonTree tr : elems) {
String snk = genEventSink(tr);
snks.add(snk);
}
return genArgs(snks, "[", ",", "]");
case DECO: {
List<CommonTree> decoNodes = (List<CommonTree>) t.getChildren();
Preconditions.checkArgument(decoNodes.size() == 2);
CommonTree deco = decoNodes.get(0);
CommonTree decoSnk = decoNodes.get(1);
String decoSink = genEventSinkDecorator(deco);
String dsnk = genEventSink(decoSnk);
return "{ " + decoSink + " => " + dsnk + " }";
}
case BACKUP: {
List<CommonTree> backupNodes = (List<CommonTree>) t.getChildren();
Preconditions.checkArgument(backupNodes.size() == 2);
CommonTree main = backupNodes.get(0);
CommonTree backup = backupNodes.get(1);
String mainSink = genEventSink(main);
String backupSink = genEventSink(backup);
return "< " + mainSink + " ? " + backupSink + " >";
}
case LET: {
List<CommonTree> backupNodes = (List<CommonTree>) t.getChildren();
Preconditions.checkArgument(backupNodes.size() == 3);
CommonTree name = backupNodes.get(0);
CommonTree sub = backupNodes.get(1);
CommonTree body = backupNodes.get(2);
String argSink = genEventSink(sub);
String bodySink = genEventSink(body);
return "let " + name.getText() + " := " + argSink + " in " + bodySink;
}
case ROLL: {
List<CommonTree> rollNodes = (List<CommonTree>) t.getChildren();
Preconditions.checkArgument(rollNodes.size() == 2);
CommonTree body = rollNodes.get(0);
CommonTree arg = rollNodes.get(1);
String bodySink = genEventSink(body);
List<String> rargs = new ArrayList<String>();
rargs.add(genArg(arg));
String argSink = genArgs(rargs, "(", ",", ")");
return "roll" + argSink + " { " + bodySink + " }";
}
case FAILCHAIN: {
// TODO (jon) This is no longer necessary with the substitution mechanisms
// found in the translators
List<CommonTree> failNodes = (List<CommonTree>) t.getChildren();
Preconditions.checkArgument(failNodes.size() >= 2);
CommonTree body = failNodes.get(0);
String bodySink = genEventSink(body);
List<String> rargs = new ArrayList<String>();
for (int i = 1; i < failNodes.size(); i++) {
CommonTree arg = failNodes.get(i);
rargs.add(genArg(arg));
}
String argSink = genArgs(rargs, "(", ",", ")");
return "failchain" + argSink + " { " + bodySink + " }";
}
// TODO (jon) handle pattern match splitter
default:
throw new FlumeSpecException("bad parse tree! expected sink but got "
+ t.toStringTree());
}
}
@SuppressWarnings("unchecked")
static String genEventSinkDecorator(CommonTree t) throws FlumeSpecException {
List<CommonTree> children = new ArrayList<CommonTree>((List<CommonTree>) t
.getChildren());
String sinkType = children.remove(0).getText();
List<String> args = new ArrayList<String>();
for (CommonTree tr : children) {
args.add(genArg(tr));
}
return sinkType + genArgs(args, "(", ",", ")");
// sinkFactory.getDecorator(sinkType, args.toArray(new String[0]));
}
@SuppressWarnings("unchecked")
public static List<FlumeNodeSpec> generate(String s)
throws FlumeSpecException {
try {
CommonTree node = FlumeBuilder.parse(s);
List<FlumeNodeSpec> cfg = new ArrayList<FlumeNodeSpec>();
if (node.getChildren() == null) {
return cfg;
}
for (CommonTree t : (List<CommonTree>) node.getChildren()) {
// -1 is magic EOF value
if (t.getType() == -1) {
break; // I am done.
}
if (t.getText() != "NODE") {
throw new FlumeSpecException("fail, expected node but had "
+ t.toStringTree());
}
String host = t.getChild(0).getText();
CommonTree tsrc = (CommonTree) t.getChild(1);
String src = genEventSource(tsrc);
CommonTree tsnk = (CommonTree) t.getChild(2);
String snk = genEventSink(tsnk);
FlumeNodeSpec entry = new FlumeNodeSpec(host, src, snk);
cfg.add(entry);
}
return cfg;
} catch (RecognitionException re) {
throw new FlumeSpecException(re.getMessage());
} catch (RuntimeException re) {
// catch other parse and lex errors
throw new FlumeSpecException(re.getMessage());
}
}
}