Uploading Structured Log

Last updated: 2020-11-09 18:49:21

    Feature Description

    This API is used to write logs to a specified log topic.

    CLS provides the following two modes:

    Load balancing mode

    In this mode, logs will be automatically written to a target partition among all readable/writable partitions under the current log topic based on the load balancing principle. This mode is suitable for scenarios where the sequential consumption is not needed.

    Sample

    POST /structuredlog?topic_id=xxxxxxxx-xxxx-xxxx-xxxx HTTP/1.1
    Host: <Region>.cls.tencentyun.com
    Authorization: <AuthorizationString>
    Content-Type: application/x-protobuf
    
    <`LogGroupList` content packaged as a PB file>

    Hash routing mode

    In this mode, data will be written to a target partition that meets the range requirements based on the hash value (x-cls-hashkey) carried by data. For example, a log source can be bound to a topic partition through hashkey, strictly guaranteeing the sequence of the data written to and consumed in this partition.

    Sample

    POST /structuredlog?topic_id=xxxxxxxx-xxxx-xxxx-xxxx HTTP/1.1
    Host: <Region>.cls.tencentyun.com
    Authorization: <AuthorizationString>
    Content-Type: application/x-protobuf
    x-cls-hashkey: xxxxxxxxxxxxxxxxxxxxxxxx
    
    <`LogGroupList` content packaged as a PB file>

    Note:

    For more information on the PB description file format and compilation steps, please see PB Compilation Sample.

    In addition, CLS allows you to upload logs in the following two modes:

    Uploading compressed logs

    In this mode, logs are compressed in lz4 format for collection, and then uploaded for retention. This mode reduces the log upload traffic (write traffic) and saves costs.

    Sample

    POST /structuredlog?topic_id=xxxxxxxx-xxxx-xxxx-xxxx HTTP/1.1
    Host: <Region>.cls.tencentyun.com
    Authorization: <AuthorizationString>
    Content-Type: application/x-protobuf
    x-cls-compress-type:lz4
    
    <`LogGroupList` content packaged as a PB file>

    Uploading original logs

    In this mode, logs are uploaded in their original size, which incurs higher log write traffic fees.

    Sample

    POST /structuredlog?topic_id=xxxxxxxx-xxxx-xxxx-xxxx HTTP/1.1
    Host: <Region>.cls.tencentyun.com
    Authorization: <AuthorizationString>
    Content-Type: application/x-protobuf
    
    <`LogGroupList` content packaged as a PB file>

    Request

    Request line

    POST /structuredlog

    Request header

    The x-cls-hashkey request header indicates that logs are written to the CLS topic partitions with a range corresponding to the hashkey route, strictly guaranteeing the write sequence of logs to each topic partition for sequential consumption.

    Field Name Type Location Required Description
    x-cls-hashkey string header No Specifies the topic partition to which the logs will be written based on hashkey

    Request parameters

    Field Name Type Location Required Description
    topic_id string query Yes ID of the target log topic to which data will be uploaded and can be viewed in the log topic page
    logGroupList message pb Yes The logGroup list, which describes the encapsulated log groups. Less than five logGroup values are recommended.

    LogGroup description:

    Field Name Required Description
    logs Yes Log array consisting of multiple Log values. The Log indicates a log, and LogGroup can contain up to 10,000 Log values
    contextFlow No UID used to maintain context, which does not take effect currently
    filename No Log filename
    source No Log source, which is generally the server IP
    logTags No Tag list of logs

    Log description:

    Field Name Required Description
    time Yes UNIX timestamp of log time in seconds (not recommended), milliseconds, or microseconds
    contents No Log content in key-value format. A log can contain multiple key-value pairs

    Content description:

    Field Name Required Description
    key Yes Key of a field group in one log, which cannot start with _
    value Yes Value of a field group, which cannot exceed 1 MB in one log. The total value cannot exceed 5 MB in LogGroup

    LogTag description:

    Field Name Required Description
    key Yes Key of a custom tag
    value Yes Value corresponding to the custom tag key

    Response

    Sample response

    HTTP/1.1 200 OK
    Content-Length: 0

    Response header

    No special response header is used except for common response header.

    Response parameters

    None.

    Error Codes

    For more information, see Error Codes.

    PB Compilation Sample

    This sample describes how to use the protoc compiler to compile the PB description file into a log upload API in C++.

    Note:

    Currently, protoc supports compilation in multiple programming languages such as Java, C++, and Python. For more information, please see protoc.

    ####. 1. Install Protocol Buffer

    Download Protocol Buffer, decompress and install it. This document uses protobuf 2.6.1 running on CentOS 7.3 as an example.
    Run the following command to decompress the protobuf-2.6.1.tar.gz package to /usr/local and access this directory:

    [root@VM_0_8_centos]# tar -zxvf protobuf-2.6.1.tar.gz -C /usr/local/ && cd /usr/local/protobuf-2.6.1

    Run the following commands to start compilation and installation, and configure the environment variables:

    [root@VM_0_8_centos protobuf-2.6.1]# ./configure 
    [root@VM_0_8_centos protobuf-2.6.1]# make && make install
    [root@VM_0_8_centos protobuf-2.6.1]# export PATH=$PATH:/usr/local/protobuf-2.6.1/bin

    After the compilation succeeds, run the following command to check the version:

    [root@VM_0_8_centos protobuf-2.6.1]# protoc --version
    liprotoc 2.6.1

    2. Create a PB description file

    A PB description file is an agreed-on data exchange format for communication. To upload logs, please compile the specified protocol format to an API in the target programming language and add the API to the project code. For more information, please see protoc.

    Create a PB message description file cls.proto based on the PB data format content specified by CLS.

    Note:

    The PB description file content cannot be modified, and the filename must end with .proto.

    The content of cls.proto (PB description file) is as follows:

    package cls;
    
    message Log
    {
        message Content
        {
            required string key   = 1; // Key of each field group
            required string value = 2; // Value of each field group
        }
        required int64   time     = 1; // Unix timestamp
        repeated Content contents = 2; // Multiple `key-value` pairs in one log
    }
    
    message LogTag
    {
        required string key       = 1;
        required string value     = 2;
    }
    
    message LogGroup
    {
        repeated Log    logs        = 1; // Log array consisting of multiple logs
        optional string contextFlow = 2; // This parameter does not take effect currently
        optional string filename    = 3; // Log filename
        optional string source      = 4; // Log source, which is generally the server IP
        repeated LogTag logTags     = 5;
    }
    
    message LogGroupList
    {
        repeated LogGroup logGroupList = 1; // Log group list
    }
    

    3. Compile and generate the API

    This sample uses the proto compiler to generate a C++ file in the same directory as the cls.proto file. Run the following compilation commands:

    protoc --cpp_out=./ ./cls.proto 
    

    Note:

    --cpp_out=./ indicates that the file will be compiled in cpp format and output to the current directory. ./cls.proto indicates the cls.proto description file in the current directory.

    After the compilation succeeds, the code file in the corresponding programming language will be output. This sample generates the cls.pb.h header file and cls.pb.cc code implementation file as shown below:

    [root@VM_0_8_centos protobuf-2.6.1]# protoc --cpp_out=./ ./cls.proto
    [root@VM_0_8_centos protobuf-2.6.1]# ls
    cls.pb.cc cls.pb.h cls.proto

    4. Call the API

    Import the generated cls.pb.h header file into the code and call the API for data format encapsulation.

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