Reading HAR file from DistributedCache in mapreduce - mapreduce

Question

I've written an oozie workflow which creates HAR archive and then runs MR-job which needs to read data from this archive.
1. Archive is created
2. When job runs, mapper does see archive in distributed cache.
3. ??? How Can I read this arhive? What's the API to read data from this archive line by line (my har is batch of multiple new line separated text files).
NB: It work perfectly when i work with usual files (not HAR archive) stored in DistirubtedCache. I got a problem while trying to read data from HAR.
Here is a code snippet:
InputStream inputStream;
String cachedDatafileName = System.getProperty(DIST_CACHE_FILE_NAME);
LOG.info(String.format("Looking for[%s]=[%s] in DistributedCache",DIST_CACHE_FILE_NAME, cachedDatafileName));
URI[] uris = DistributedCache.getCacheArchives(getContext().getConfiguration());
URI uriToCachedDatafile = null;
for(URI uri : uris){
if(uri.toString().endsWith(cachedDatafileName)){
uriToCachedDatafile = uri;
break;
}
}
if(uriToCachedDatafile == null){
throw new RuntimeConfigurationException(String.format("Looking for[%s]=[%s] in DistributedCache failed. There is no such file",
DIST_CACHE_FILE_NAME, cachedDatafileName));
}
Path pathToFile = new Path(uriToCachedDatafile);
LOG.info(String.format("[%s] has been found. Uri is: [%s]. The path is:[%s]",cachedDatafileName, uriToCachedDatafile, pathToFile));
FileSystem fileSystem = pathToFile.getFileSystem(getContext().getConfiguration());
HarFileSystem harFileSystem = new HarFileSystem(fileSystem);
inputStream = harFileSystem.open(pathToFile); //NULL POINTER EXCEPTION IS HERE!
return inputStream;

Answer 1

protected InputStream getInputStreamToDistCacheFile() throws IOException{
InputStream inputStream;
String cachedDatafileName = System.getProperty(DIST_CACHE_FILE_NAME);
LOG.info(String.format("Looking for[%s]=[%s] in DistributedCache",DIST_CACHE_FILE_NAME, cachedDatafileName));
URI[] uris = DistributedCache.getCacheArchives(getContext().getConfiguration());
URI uriToCachedDatafile = null;
for(URI uri : uris){
if(uri.toString().endsWith(cachedDatafileName)){
uriToCachedDatafile = uri;
break;
}
}
if(uriToCachedDatafile == null){
throw new RuntimeConfigurationException(String.format("Looking for[%s]=[%s] in DistributedCache failed. There is no such file",
DIST_CACHE_FILE_NAME, cachedDatafileName));
}
//Path pathToFile = new Path(uriToCachedDatafile +"/stf/db_bts_stf.txt");
Path pathToFile = new Path("har:///"+"home/ssa/devel/megalabs/kyc-solution/kyc-mrjob/target/test-classes/GSMCellSubscriberHomeIntersectionJobDescriptionClusterMRTest/in/gsm_cell_location_stf.har" +"/stf/db_bts_stf.txt");
//Path pathToFile = new Path(("har://home/ssa/devel/megalabs/kyc-solution/kyc-mrjob/target/test-classes/GSMCellSubscriberHomeIntersectionJobDescriptionClusterMRTest/in/gsm_cell_location_stf.har"));
LOG.info(String.format("[%s] has been found. Uri is: [%s]. The path is:[%s]",cachedDatafileName, uriToCachedDatafile, pathToFile));
FileSystem harFileSystem = pathToFile.getFileSystem(context.getConfiguration());
FSDataInputStream fin = harFileSystem.open(pathToFile);
LOG.info("fin: " + fin);
// FileSystem fileSystem = pathToFile.getFileSystem(getContext().getConfiguration());
// HarFileSystem harFileSystem = new HarFileSystem(fileSystem);
// harFileSystem.exists(new Path("har://home/ssa/devel/mycompany/my-solution/my-mrjob/target/test-classes/HomeJobDescriptionClusterMRTest/in/locations.har"));
// LOG.info("harFileSystem.exists(pathToFile):"+ harFileSystem.exists(pathToFile));
// harFileSystem.initialize(uriToCachedDatafile, context.getConfiguration());
FileStatus[] statuses = harFileSystem.listStatus(new Path("har:///"+"har://home/ssa/devel/mycompany/my-solution/my-mrjob/target/test-classes/HomeJobDescriptionClusterMRTest/in/locations.har"));
for(FileStatus fileStatus : statuses){
LOG.info("fileStatus isDir"+fileStatus.isDirectory() +" len:" + fileStatus.getLen());
}
// String tmpPathToFile = "har:///"+pathToFile.toString(); //+"/stf/db_bts_stf.txt";
// Path tmpPath = new Path(tmpPathToFile);
// LOG.info("KILL ME PATH TO FILE IN ARCHIVE: " +tmpPath);
// inputStream = harFileSystem.open(tmpPath);
// return inputStream;
return fin;
}
As you can see, it's terrible. You have manually read index file stored inside archive and reconstruct paths using index file metadata. If you know the exact name of a file stored in archive (like in my example), you can construct paths manually.
It's not convinient.I did expect something like Zip->zipEntry, when you can iterate over entries of archive without knowing it's structure.