Home | About | Sematext search-lucene.com search-hadoop.com
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB
 Search Hadoop and all its subprojects:

Switch to Plain View
Pig >> mail # user >> Restricting loading of log files based on parameter input


+
Stevens, Ian 2013-02-14, 22:16
+
Cheolsoo Park 2013-02-15, 21:53
Copy link to this message
-
RE: Restricting loading of log files based on parameter input
Thanks for this Cheolsoo. I started work on a LoadFunc assuming it was an easy win, although I hate that I have to do this. It's just text concatenation after all. Moving the logic of our log path structure to a Java class or an external package is wrong from a maintenance standpoint.

How familiar are you (or anyone) with creating a custom LoadFunc? The documentation I've found is sparse. Is there a method I can override which considers reading on a file-by-file basis? Our Omniture logs have a date stamp in the filename, and it would be more maintainable to reject a file based on its basename rather than its path. We're more likely to change our paths than change the filenames, so this would mean the code has a better chance of standing the test of time.

Cheers,
Ian.

-----Original Message-----
From: Cheolsoo Park [mailto:[EMAIL PROTECTED]]
Sent: February-15-13 4:53 PM
To: [EMAIL PROTECTED]
Subject: Re: Restricting loading of log files based on parameter input

Hi Ian,

1) Pre-processor statements are just text substitution, so you can't call a Python (or Java) function inside %declare.

2) Regarding DEFINE statements, there are two problems using them with scripting UDF:
- You can't pass constructor parameters to scripting UDF.
- You can't use scripting UDF for Load/StoreFunc.

Given these constraints, I think writing a Java LoadFunc seems to be the best option. I would write a sub-class of OmnitureTextLoader in such a way that it can take constructor parameters. For example,

class MyOmnitureTextLoader extends OmnitureTextLoader {

  private String year;
  private String month;

  public MyOmnitureTextLoader() { ... }
  public MyOmnitureTextLoader(String year, String month) { ... }

  @Override
  setLocation(String location, Job job) {
    // Compute week path with year and month and replace location with that.
  }
}

Then, you can do something like in Pig:

DEFINE WEEK_PATH_LOADER MyOmnitureTextLoader($year, $month);

A = LOAD 'replace_me_with_week_path' USING WEEK_PATH_LOADER;

Hope this is helpful.

Thanks,
Cheolsoo
On Thu, Feb 14, 2013 at 2:16 PM, Stevens, Ian
<[EMAIL PROTECTED]>wrote:

> Hi everyone. I'm having a problem loading log files based on parameter
> input and was wondering whether someone would be able to provide some
> guidance. The logs in question are Omniture logs, stored in
> subdirectories based on year, month, and day (eg.
> /year=2013/month=02/day=14). For any day, multiple logs could exist, each hundreds of MB.
>
> I have a Pig script which currently processes logs for an entire
> month, with the month and the year specified as script parameters (eg.
> /year=$year/month=$month/day=*). It works fine and we're quite happy
> with it. That said, we want to switch to weekly processing of logs,
> which means the previous LOAD path glob won't work (weeks can wrap
> months as well as years). To solve this, I have a Python UDF which
> takes a start date and spits out the necessary glob for a week's worth of logs, eg:
>
>                 >>> log_path_regex(2013, 1, 28)
>
> '{year=2013/month=01/day=28,year=2013/month=01/day=29,year=2013/month=01/day=30,year=2013/month=01/day=31,year=2013/month=02/day=01,year=2013/month=02/day=02,year=2013/month=02/day=03}'
>
> This glob will then be inserted in the appropriate path:
>
>                 > %declare omniture_log_path
> 's3://foo/bar/$week_path/*.tsv.gz';
>                 > data = LOAD '$omniture_log_path' USING
> OmnitureTextLoader(); // See
> http://github.com/msukmanowsky/OmnitureTextLoader
>
> Unfortunately, I can't for the life of me figure out how to populate
> $week_path based on $year, $month and $day script parameters. I tried
> using %declare but grunt complains, says its logging but never does:
>
> > %declare week_path util.log_path_regex(year, month, day);
> 2013-02-14 16:54:02,648 [main] INFO  org.apache.pig.Main - Apache Pig
> version 0.10.1 (r1426677) compiled Dec 28 2012, 16:46:13
>
> 2013-02-1416:54:02,648 [main] INFO  org.apache.pig.Main - Logging
+
Cheolsoo Park 2013-02-20, 19:39
+
Stevens, Ian 2013-02-20, 20:05
+
Stevens, Ian 2013-02-15, 21:59
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB