由于globStatus，MapReduce作业未产生输出

Question

I'm not sure why my Mapper and Reducer have no output. The logic behind my code is, given a file of UUIDs (new line separated), I want to use globStatus to display all the paths to all potential files that the UUID might be in. Open and read the file. Each file contains 1-n lines of JSON. The UUID is in event_header.event_id in the JSON.

Right now the MapReduce job runs without errors. However, something is wrong because I dont have any output. I'm not sure how to debug MapReduce jobs as well. If someone could provide me a source that would be awesome! The expected output from this program should be

fee90c3f-e832-4267-aa9b-250f53kc06d3 1
914938ae-eed6-4dfa-81bf-71e67m42d93a 1
bbge6012-9c51-4ae1-9242-a4aaf08bfb36 1
e5a12493-gtrf-4ar4-9235-02fd3h580970 1
3b054300-09ba-4d59-a6ac-a0975ca74ed5 1
6fbb1c5g-15ce-4e6f-9236-55a9d9d6e2c6 1
ab4677a3-0f58-428c-8h58-5fe3dfe528dc 1
caaa011d-ahba-4ne7-9h05-3872f3k1854c 1

example JSON:

{"event_header":{"version":"1.0","event_id":"fdk32k23-f7f6-412d-879d-f79b4c3b0d55","server_timestamp":1427734304673,"client_ip_address":"10.144.28.48","server_ip_address":"10.129.67.0"},"data_version":"1.0","application":{"properties":{}},"session":{"test":false,"user_id":"1121057496"},"event":{"timestamp":"1427734304577","event_category":"User","traffic":{"priority_code":"1728300000"},"event_id":"9ad26251-b940-408a-b6a9-0a825be1fd38","event_name":"Create"}}

In my logic, the output file should be the UUIDs with a 1 next to them because upon found, 1 is written, if not found 0 is written. They should be all 1's because I pulled the UUIDs from the source.

I added the line context.write(new Text("None"), new Text("blank")) in the for loop and I have found out that nothing is being written to output. So I think I can safely conclude that I am using globStatus() link incorrectly.

My Reducer currently does not do anything except I just wanted to see if I could get some simple logic working. There are most likely bugs in my code as I dont know have a easy way to debug MapReduce jobs.

Driver:

public class SearchUUID {

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf, "UUID Search");
        job.getConfiguration().set("mapred.job.queue.name", "exp_dsa");
        job.setJarByClass(SearchUUID.class);
        job.setMapperClass(UUIDMapper.class);
        job.setReducerClass(UUIDReducer.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}

UUIDMapper:

public class UUIDMapper extends Mapper<Object, Text, Text, Text> {
    public void map(Object key, Text value, Context context) throws IOException, InterruptedException {

        try {
            Text one = new Text("1");
            Text zero = new Text("0");

            FileSystem fs = FileSystem.get(new Configuration());
            FileStatus[] paths = fs.globStatus(new Path("/data/path/to/file/d_20150330-1650"));
            for (FileStatus path : paths) {
                BufferedReader br = new BufferedReader(new InputStreamReader(fs.open(path.getPath())));
                String json_string = br.readLine();
                while (json_string != null) {
                    JsonElement jelement = new JsonParser().parse(json_string);
                    JsonObject jsonObject = jelement.getAsJsonObject();
                    jsonObject = jsonObject.getAsJsonObject("event_header");
                    jsonObject = jsonObject.getAsJsonObject("event_id");

                    if (value.toString().equals(jsonObject.getAsString())) {
                        System.out.println(value.toString() + "slkdjfksajflkjsfdkljsadfk;ljasklfjklasjfklsadl;sjdf");
                        context.write(value, one);
                    } else {
                        context.write(value, zero);
                    }

                    json_string = br.readLine();
                }
            }
        } catch (IOException failed) {
        }
    }
}

Reducer:

public class UUIDReducer extends Reducer<Text, Text, Text, Text>{

    public void reduce(Text key, Text value, Context context) throws IOException, InterruptedException{
        context.write(key, value);
    }
}

Answer 1

did you check userlogs inside log folder? following code works fine

jsonObject = jsonObject.getAsJsonObject("event_header"); jsonObject = jsonObject.getAsJsonObject("event_id"); This line is not correct use jsonObject.get("event_header").getAsJsonObject(); jsonObject.get("event_id").getAsJsonObject(); proble is in geting event_header,event_id JSONOBJECT.

public class UUIDMapper extends Mapper < Object, Text, Text, Text > {
    public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
        try {
            Text one = new Text("1");
            Text zero = new Text("0");
            String json_string[] = {
                "your data", "your data", "your data", "your data "
            };
            int i = 0;
            while (i < json_string.length) {
                if (value.toString().equals(json_string[i])) {
                    context.write(value, one);
                } else {
                    context.write(value, zero);
                }
            }
        } catch (Exception t) {
            t.printStackTrace();
        }
    }
}