在 PIG 中读取带有模式的文件

Question

我有一个场景，我使用 HCatStorer 将 40 个具有不同模式的文件从目录加载到 Hive 表。

Directory : opt/inputfolder/ 
Input Files Pattern :

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

我写了一个pig-script，它可以读取所有具有 40 种模式的文件。

但我的问题是，这 40 个文件是强制性的，我可能不会收到一些文件。在这种情况下，我收到一个异常说明：

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

有没有办法处理这个异常？

我想读取剩余的 39 个带有模式的文件，即使该文件不存在。

如果我的源文件是字符串（例如，banana_2014012.log,orange_2014012.log,apple_2014012.log）怎么办

以下是我使用 HCatStorer 将这些文件中的数据加载到 HIVE 表的方法。

*** 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;

如果任何 src 没有文件，则此 Pig 脚本将抛出错误，指出匹配模式为 0，并且 PIG 脚本将失败。即使一个源文件不可用，我希望我的脚本加载其他表不会让我的工作失败。

谢谢。

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