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[英]Read data from BigQuery and write it into avro file format on cloud storage
[英]GCP Dataflow- read CSV file from Storage and write into BigQuery
我在存儲中有一個CSV文件,我想讀取它並將其寫入BigQuery表。 這是我的CSV文件,其中第一行是標題:
GroupName,Groupcode,GroupOwner,GroupCategoryID
System Administrators,sysadmin,13456,100
Independence High Teachers,HS Teachers,,101
John Glenn Middle Teachers,MS Teachers,13458,102
Liberty Elementary Teachers,Elem Teachers,13559,103
1st Grade Teachers,1stgrade,,104
2nd Grade Teachers,2nsgrade,13561,105
3rd Grade Teachers,3rdgrade,13562,106
Guidance Department,guidance,,107
Independence Math Teachers,HS Math,13660,108
Independence English Teachers,HS English,13661,109
John Glenn 8th Grade Teachers,8thgrade,,110
John Glenn 7th Grade Teachers,7thgrade,13452,111
Elementary Parents,Elem Parents,,112
Middle School Parents,MS Parents,18001,113
High School Parents,HS Parents,18002,114
這是我的代碼:
public class StorgeBq {
public static class StringToRowConverter extends DoFn<String, TableRow> {
private String[] columnNames;
private boolean isFirstRow = true;
@ProcessElement
public void processElement(ProcessContext c) {
TableRow row = new TableRow();
String[] parts = c.element().split(",");
if (isFirstRow) {
columnNames = Arrays.copyOf(parts, parts.length);
isFirstRow = false;
} else {
for (int i = 0; i < parts.length; i++) {
row.set(columnNames[i], parts[i]);
}
c.output(row);
}
}
}
public static void main(String[] args) {
DataflowPipelineOptions options = PipelineOptionsFactory.fromArgs(args).withValidation()
.as(DataflowPipelineOptions.class);
options.setZone("europe-west1-c");
options.setProject("mydata-dev");
options.setRunner(DataflowRunner.class);
Pipeline p = Pipeline.create(options);
p.apply("ReadLines", TextIO.read().from("gs://mydata3-dataflow/C2ImportGroupsSample.csv"))
.apply("ConverToBqRow",ParDo.of(new StringToRowConverter()))
.apply("WriteToBq", BigQueryIO.<TableRow>writeTableRows()
.to("mydata-dev:DF_TEST.dataflow_table")
.withWriteDisposition(WriteDisposition.WRITE_APPEND)
.withCreateDisposition(CreateDisposition.CREATE_NEVER));
p.run().waitUntilFinish();
}
}
存在一些問題:1)當作業開始執行時,我看到有一個名為“ DropInputs”的進程,我的代碼中尚未定義該進程! 並開始在所有任務之前運行,為什么?
2)為什么管道不以第一個任務“ ReadLines”開頭? 3)在日志文件中,我看到在任務“ WriteToBq”中它嘗試查找其中一個數據作為字段,例如“ 1st Year Teachers”不是字段,而是“ GroupName”的數據:
"message" : "JSON parsing error in row starting at position 0: No such field: 1st Grade Teachers.",
您的代碼中有幾個問題。 但是,首先,對於“ DropInputs”階段-您可以放心地忽略它。 這是此錯誤報告的結果。 我仍然不明白為什么需要顯示它(它也使我們的很多用戶感到困惑),並且我很希望Googler能夠對此加以介紹。 我認為這只是混亂。
正確,現在輸入您的代碼:
boolean
標志進行檢查,而是每次在ParDo
檢查string
值本身,例如, if (c.element.contains("GroupName") then..
withSchema(..)
。 這是我的一個公共管道中的一個示例 。
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