ExAliyunSls

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Description

ExAliyunSls is an Elixir SDK client for Aliyun SLS (阿里云日志服务). It allows you to push your logs to Aliyun Log Service, making them more convenient for statistics, visualization, and analysis.

Features

  • Logger backend for sending logs to Aliyun SLS
  • Custom Plug for Phoenix applications
  • Parameter filtering for sensitive data
  • Embedded page integration for viewing logs in your application
  • Batched log sending with configurable package size and timeout

Installation

The package can be installed by adding :ex_aliyun_sls to your list of dependencies in mix.exs:

def deps do
  [
    {:ex_aliyun_sls, "~> 0.4"}
  ]
end

Logging Methods

In Elixir, you can log in the following ways:

Logger.debug "test1" #1
Logger.info fn -> "test2" end #2
Logger.info fn -> {"test3", [meta1: "meta1", meta2: "meta2", meta3: "meta3"]} end #3
  • Example #1 is the log content will be pushed as msg in debug level.
  • Example #2 is the simliar as #1, but it may be better for performance as the string is only evaluated if the log level is enabled.
  • Example #3 is the recommended approach, the first element of the tuple will be set as msg, and the second element (the keyword list) contains metadata that will be pushed as independent fields like meta1, meta2, meta3.

Configuration

Aliyun SLS Configuration

Add your Aliyun SLS information to config/config.exs with the following options:

config :ex_aliyun_sls, :backend,
  endpoint: "YOUR SLS ENDPOINT",
  access_key_id: "YOUR ACCESS KEY ID",
  access_key: "YOUR ACCESS KEY",
  project: "YOUR SLS PROJECT NAME",
  logstore: "YOUR LOG STORE NAME",
  package_count: 100, # Default to 100
  package_timeout: 10_000, # Optional, Default to nil
  scheme: "https", # Default to "https"
  filtered_params: ["password", "token"] # Optional, for filtering sensitive data

Configuration Options:

  • endpoint: The Aliyun SLS service endpoint (required)
  • access_key_id: Your Aliyun RAM user access key ID (required)
  • access_key: Your Aliyun RAM user access key secret (required)
  • project: Your SLS project name (required)
  • logstore: Your SLS logstore name (required)
  • package_count: Maximum number of logs to push per batch, default is 100
  • package_timeout: Maximum time (in milliseconds) to wait before pushing logs, default is nil when using ExAliyunSls.LoggerBackend, set this if you want to clear logs regularly
  • scheme: The HTTP scheme for requests to Aliyun Cloud Server, default is "https"
  • filtered_params: List of parameter names that should be filtered from logs for privacy/security

Please ensure the access_key_id and access_key are correct and have the necessary permissions to write to your SLS project.

Logger Configuration 

config :logger,
  backends: [
    {ExAliyunSls.LoggerBackend, :sls_log},
  ]

The atom :sls_log is just an identifier for the backend - you can use any atom you prefer. You can also add other logger backends alongside this one.

Configure which metadata to include in your logs:

config :logger, :sls_log,
  level: :info, # Optional, sets minimum log level
  metadata: [:pid, :module, :file, :line, :function, :application]

Metadata Options:

  • Set metadata to :all to include all available metadata in your logs
  • Set metadata to a list of specific metadata keys you want to include
  • When using the Phoenix integration, the following metadata is automatically included: [:duration, :method, :status, :state, :request_path, :params]
  • Default metadata when using :all includes [:pid, :module, :file, :line]

Log Level Filtering

You can set a minimum log level for the SLS backend:

config :logger, :sls_log,
  level: :info

This will only log messages with a level of :info or higher.

Phoenix Integration

Your logs through Phoenix endpoint are set by default by Plug.Logger . If you want to push them to Aliyun SLS, you should use our plug instead.

Replace the Plug Logger Handler 

# This is the endpoint.ex in your phoenix project
# plug Plug.Logger
plug ExAliyunSls.Plug.Logger

With this configuration, your logs will be formatted as:

Logger.info fn ->
  {
    "GET: /login, status=200, duration=0.443ms",
    [
      duration: "0.443ms",
      status: 200,
      method: "GET",
      state: "set",
      request_path: "/login",
      params: "{your params will be formatted to json}"
    ]
  }
end

Your logs for plug will appear as "GET: /login, Sent 200 in 0.443ms", and it will push the metadata duration, method, request_path, status, state, and params to Aliyun SLS.

Filter Sensitive Parameters

If you have parameters that should not be logged, you can filter them by setting filtered_params in the config file:

config :ex_aliyun_sls, :backend,
  endpoint: "YOUR SLS ENDPOINT",
  access_key_id: "YOUR ACCESS KEY ID",
  access_key: "YOUR ACCESS KEY",
  project: "YOUR SLS PROJECT NAME",
  logstore: "YOUR LOG STORE NAME",
  package_count: 100,
  package_timeout: 10_000,
  filtered_params: ["password", "token", "credit_card", "secret"] # Add your filtered params here

Filtered parameters in HTTP requests will be replaced with "**" in the logs.

Embedded Page Integration

To check and search logs in the Aliyun SLS dashboard, you can add an embedded page to your own website.

Configuration

Create a role in the Aliyun RAM Access Control Console, set the proper attributes of the role and related permissions.

config :ex_aliyun_sls, :embed_page,
  access_key_id: "YOUR SLS ACCESS KEY ID",
  access_key_secret: "YOUR SLS ACCESS KEY SECRET",
  role_arn: "YOUR ROLE ARN",
  login_page: "YOUR LOGIN PAGE URL",
  destination: "YOUR DESTINATION URL"

Important: The above access_key_id and access_key_secret still come from the RAM user, which can be given specialized permissions to assume roles via the AliyunSTSAssumeRoleAccess authorization policy.

How to Use It

You can use ExAliyunSls.EmbedPage.get_url/7 to get the embedded page's URL:

get_url(access_key_id, access_key_secret, role_arn, login_page, destination_page, duration_seconds \\ 3600, role_session_name \\ "default")
  • role_arn: It is created in the Aliyun RAM Access Control Console - Role section, the format is acs:ram::$accountID:role/$roleName, such as acs:ram::1234567890123456:role/samplerole.
  • login_page: The page to redirect to when the embedded page fails to load.
  • destination_page: The SLS dashboard page you want to add to your page, these types are supported:
    • Full log search page : https://sls.console.aliyun.com/next/project/<Project名称>/logsearch/<日志库名称>?hideTopbar=true&hideSidebar=true
    • Log search page : https://sls.console.aliyun.com/next/project/<Project名称>/logsearch/<日志库名称>?isShare=true&hideTopbar=true&hideSidebar=true
    • Dashboard page : https://sls.console.aliyun.com/next/project/<Project名称>/dashboard/<仪表盘名称>?isShare=true&hideTopbar=true&hideSidebar=true

Example Implementation 

def get_embedded_dashboard_url do
  config = Application.get_env(:ex_aliyun_sls, :embed_page)
  
  {:ok, url} = ExAliyunSls.EmbedPage.get_url(
    config[:access_key_id],
    config[:access_key_secret],
    config[:role_arn],
    config[:login_page],
    config[:destination]
  )
  
  url
end

Advanced Usage

Batch Log Processing

The SDK automatically batches logs based on the package_count and package_timeout settings:

  • When the number of logs reaches package_count, they are automatically sent to Aliyun SLS
  • If package_timeout is set, logs will be sent after that duration even if the count hasn't been reached
  • Logs are also flushed when the application terminates

This approach optimizes network usage while ensuring logs are delivered in a timely manner.

Local Development

Use the following configuration to run the tests:

import Config

config :logger,
  backends: [
    {ExAliyunSls.LoggerBackend, :sls},
  ]
  
config :ex_aliyun_sls, :backend,
  endpoint: "...",
  access_key_id: "..."
  access_key: "..."
  project: "...",
  logstore: "...",
  package_count: 10,
  package_timeout: 5_000

config :ex_aliyun_sls, :embed_page,
  endpoint: "...",
  access_key_id: "...",
  access_key_secret: "...",
  role_arn: "..."

Copyright (c) 2019 eDragonConnect

This work is free. You can redistribute it and/or modify it under the terms of the MIT License. See the LICENSE.md file for more details.