Go开发的基于Hadoop的ETL抽取工具：Crunch
jopen
10年前
快速开发，快速运行，基于Go工具包。实现基于 Hadoop 的 ETL 和特性抽取工具。
快速入门
Crunch is optimized to be a big-bang-for-the-buck libary, yet almost every aspect is extensible.
Let's say you have a log of semi-structured and deeply nested JSON. Each line contains a record.
You would like to:
- Parse JSON records
- Extract fields
- Cleanup/process fields
- Extract features - run custom code on field values and output the result as new field(s)
所以这里有一个详细的视图：
// Describe your row transform := crunch.NewTransformer() row := crunch.NewRow() // Use "field_name type". Types are Hive types. row.FieldWithValue("ev_smp int", "1.0") // If no type given, assume 'string' row.FieldWithDefault("ip", "0.0.0.0", makeQuery("head.x-forwarded-for"), transform.AsIs) row.FieldWithDefault("ev_ts", "", makeQuery("action.timestamp"), transform.AsIs) row.FieldWithDefault("ev_source", "", makeQuery("action.source"), transform.AsIs) row.Feature("doing ip to location", []string{"country", "city"}, func(r crunch.DataReader, row *crunch.Row)[]string{ // call your "standard" Go code for doing ip2location return ip2location(row["ip"]) }) // By default, will build a hadoop-compatible streamer process that understands json: (stdin[JSON] to stdout[TSV]) // Also will plug-in Crunch's CLI utility functions (use -help) crunch.ProcessJson(row)