如何解析 OpenTelemetry 1.0.0 消息

本節提供的資訊可協助您開始剖析 OpenTelemetry 1.0.0。

首先，您應該獲得特定於語言的綁定，這使您能夠以首選語言解析 OpenTelemetry 1.0.0 消息。

下列章節包含使用特定語言的連結的範例，您可以依照先前指示建置相關連結。

Java

package com.example;

import io.opentelemetry.proto.collector.metrics.v1.ExportMetricsServiceRequest;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class MyOpenTelemetryParser {

    public List<ExportMetricsServiceRequest> parse(InputStream inputStream) throws IOException {
        List<ExportMetricsServiceRequest> result = new ArrayList<>();

        ExportMetricsServiceRequest request;
        /* A Kinesis record can contain multiple `ExportMetricsServiceRequest`
           records, each of them starting with a header with an
           UnsignedVarInt32 indicating the record length in bytes:
            ------ --------------------------- ------ -----------------------
           |UINT32|ExportMetricsServiceRequest|UINT32|ExportMetricsService...
            ------ --------------------------- ------ -----------------------
         */
        while ((request = ExportMetricsServiceRequest.parseDelimitedFrom(inputStream)) != null) {
            // Do whatever we want with the parsed message
            result.add(request);
        }

        return result;
    }
}

Javascript

此範例假設已產生連結的根資料夾為 ./

函數的資料引數 parseRecord 可為下列其中一種類型：

const pb = require('google-protobuf')
const pbMetrics =
    require('./opentelemetry/proto/collector/metrics/v1/metrics_service_pb')

function parseRecord(data) {
    const result = []

    // Loop until we've read all the data from the buffer
    while (data.length) {
        /* A Kinesis record can contain multiple `ExportMetricsServiceRequest`
           records, each of them starting with a header with an
           UnsignedVarInt32 indicating the record length in bytes:
            ------ --------------------------- ------ -----------------------
           |UINT32|ExportMetricsServiceRequest|UINT32|ExportMetricsService...
            ------ --------------------------- ------ -----------------------
         */
        const reader = new pb.BinaryReader(data)
        const messageLength = reader.decoder_.readUnsignedVarint32()
        const messageFrom = reader.decoder_.cursor_
        const messageTo = messageFrom + messageLength

        // Extract the current `ExportMetricsServiceRequest` message to parse
        const message = data.subarray(messageFrom, messageTo)

        // Parse the current message using the ProtoBuf library
        const parsed =
            pbMetrics.ExportMetricsServiceRequest.deserializeBinary(message)

        // Do whatever we want with the parsed message
        result.push(parsed.toObject())

        // Shrink the remaining buffer, removing the already parsed data
        data = data.subarray(messageTo)
    }

    return result
}

Python

您必須自行閱讀 var-int 分隔符或使用內部方法 _VarintBytes(size) 和 _DecodeVarint32(buffer, position)。這些傳回緩衝區中的位置恰好在大小位元組之後。讀取端可構造一個新的緩衝區，且僅限於讀取訊息的位元組。

size = my_metric.ByteSize()
f.write(_VarintBytes(size))
f.write(my_metric.SerializeToString())
msg_len, new_pos = _DecodeVarint32(buf, 0)
msg_buf = buf[new_pos:new_pos+msg_len]
request = metrics_service_pb.ExportMetricsServiceRequest()
request.ParseFromString(msg_buf)

Go

請使用 Buffer.DecodeMessage()。

C#

請使用 CodedInputStream。該列表可以讀取以大小分隔的訊息。

C++

google/protobuf/util/delimited_message_util.h 中描述的函數可以讀取以大小分隔的訊息。

其他語言

如需其他語言，請參閱下載協定緩衝區。

實作剖析器時，請考慮 Kinesis 記錄可以包含多個 ExportMetricsServiceRequest 協定緩衝區訊息，每個訊息都以具有 UnsignedVarInt32 的標題為開頭，而該標題可指示記錄長度 (以位元組為單位)。