在PIG中读取带有模式的文件

Question

I have a scenario, where I am loading 40 files with different patterns from a directory to Hive Tables using HCatStorer .

Directory : opt/inputfolder/ 
Input Files Pattern :

inp1*.log,
inp2*.log,
    .....
inp39*.log,
inp40*.log.

I have written a pig -script which reads all the files with 40 patterns.

But my problem is, these 40 files is mandatory and I may not receive some files. In which case, I am getting an exception stating:

Caused by: org.apache.hadoop.mapreduce.lib.input.InvalidInputException:
           Input Pattern opt/ip_files/inp16*.log matches 0 files

Is there any way to handle this exception?

I want to read the remaining 39 files with pattern even though this file is not present.

What if my source files are in string (ie banana_2014012.log,orange_2014012.log,apple_2014012.log)

The following is my Approach for loading data from these files to HIVE Table using HCatStorer.

*** Pseudo code ****
banana_src = LOAD banana_*.log' using PigStorage;
......
Store banana_src into BANANA using HCatStorer;

apple_src = LOAD banana_*.log' using PigStorage;
......
Store apple_src into APPLE using HCatStorer;

orange_src = LOAD banana_*.log' using PigStorage;
......
Store orange_src into ORANGE using HCatStorer;

If any of the src is not having files then this Pig script will throw error saying Match Pattern is 0 and PIG Scrip will be in FAILED.Even though one source file is not available, I want my scrip to load the other tables without failing my Job.

Thanks.

Answer 1

 If you load inp1*.log, it matches inp16*.log also(if file present) but why are you again
 loading inp16*.log separately?

 Based on the above input i feel the below condition is sufficient for you.
        LOAD 'opt/ip_files/inp[1-9]*.log'

Please let me know if you are trying something different?

UPDATE:
I have one more option but not sure if this works for you.
1. Split your pig script into three parts say banana.pig, apple.pig and orange.pig each script will have their own logic.
2. Write a shell script to check existence of the each file pattern
3. If the files are present, call the corresponding pig script using pig params option else dont call. 
   In this option, if the files are not present that particular pig script will not be get triggred

Shellscript: test.sh
#!/bin/bash

BANANA_FILES="opt/ip_files/banana_*.log"
APPLE_FILES="opt/ip_files/apple_*.log"
ORANGE_FILES="opt/ip_files/orange_*.log"

if ls $BANANA_FILES > /dev/null 2>&1
then
    echo "Banana File Found"
    pig -x local -param PIG_BANANA_INPUT_FILES="$BANANA_FILES" -f banana.pig
else
    echo "No Banana files found"
fi

if ls $APPLE_FILES > /dev/null 2>&1
then
    echo "Apple File Found"
    pig -x local -param PIG_APPLE_INPUT_FILES="$APPLE_FILES" -f apple.pig
else
    echo "No APPLE files found"
fi

if ls $ORANGE_FILES > /dev/null 2>&1
then
    echo "Orange File Found"
    pig -x local -param PIG_ORANGE_INPUT_FILES="$ORANGE_FILES" -f orange.pig
else
    echo "No Orange files found"
fi


PigScript:banana.pig
banana_src = LOAD '$PIG_BANANA_INPUT_FILES' using PigStorage;
DUMP banana_src;

PigScript: apple.pig
apple_src = LOAD '$PIG_APPLE_INPUT_FILES' using PigStorage;
DUMP apple_src;

PigScript:orange.pig
orange_src = LOAD '$PIG_ORANGE_INPUT_FILES' using PigStorage;
DUMP orange_src;

Output1: All the three files are present
$ ./test.sh 
Banana File Found
(1,2,3,4,5)
(a,b,c,d,e)
Apple File Found
(test1,test2)
Orange File Found
(13,4,5)

Output2: Only banana files are present
$ ./test.sh 
Banana File Found
(1,2,3,4,5)
(a,b,c,d,e)
No APPLE files found
No Orange files found