如何在AWS Lambda中正确加载gem扩展

Question

我在AWS Lambda上遇到gem加载错误时遇到问题。

{
  "errorMessage": "LoadError: libpq.so.5: cannot open shared object file: No such file or directory - /var/task/vendor/bundle/ruby/2.5.0/gems/pg-1.1.4/lib/pg_ext.so",
  "errorType": "Function<Sequel::AdapterNotFound>",
  "stackTrace": [
    "/var/lang/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'",
    "/var/lang/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/pg-1.1.4/lib/pg.rb:4:in `<top (required)>'",
    "/var/lang/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'",
    "/var/lang/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/sequel-5.16.0/lib/sequel/adapters/postgres.rb:6:in `<top (required)>'",
    "/var/lang/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'",
    "/var/lang/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/sequel-5.16.0/lib/sequel/database/connecting.rb:88:in `load_adapter'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/sequel-5.16.0/lib/sequel/database/connecting.rb:17:in `adapter_class'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/sequel-5.16.0/lib/sequel/database/connecting.rb:45:in `connect'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/sequel-5.16.0/lib/sequel/core.rb:121:in `connect'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/sequel-5.16.0/lib/sequel/core.rb:399:in `adapter_method'",
    "/var/task/vendor/bundle/ruby/2.5.0/gems/sequel-5.16.0/lib/sequel/core.rb:406:in `block (2 levels) in def_adapter_method'",
    "/var/task/lib/warehouse/loader.rb:5:in `connection'",
    "/var/task/lib/warehouse/loader.rb:24:in `initialize'",
    "/var/task/lib/warehouse/update.rb:43:in `new'",
    "/var/task/lib/warehouse/update.rb:43:in `block in handle'",
    "/var/task/lib/warehouse/update.rb:42:in `each'",
    "/var/task/lib/warehouse/update.rb:42:in `handle'",
    "/var/task/lambda.rb:11:in `handler'"
  ]
}

我正在使用Sequel库从AWS Lambda建立PSQL连接，但似乎该函数找不到so文件。我已经在vendor/bundle中打包了依赖项，在CodeBuild上用Ubuntu构建，并验证了.so文件存在于上传到lambda的结果工件中。我还编辑了$ LOAD_PATH，但这似乎没有帮助。

其他人遇到过这个困难？有关解决或调试的任何进一步提示？

Answer 1

你的libpq.so.5文件夹上有lib吗？

您的错误是在libpq.so.5上没有找到$PATH，在AWS Lambda中，文件夹lib会自动加载到路径上，因此，您只需要在此处拥有此文件。

在lambda世界之外创建的可执行文件不在Lambda上运行，此外，您需要在Lambda映像上自己编译可执行文件。这是如何做到这一点的一个例子：

的Gemfile

source "https://rubygems.org"

gem "pg"
gem "mysql2"

handler.rb

require 'pg'
require 'mysql2'

def run(event:, context:)
  {
    postgres_client_version: PG.library_version,
    mysql_client_version: Mysql2::VERSION
  }
end

Dockerfile

FROM lambci/lambda:build-ruby2.5

RUN yum install -y postgresql postgresql-devel mysql mysql-devel
RUN gem update bundler

ADD Gemfile /var/task/Gemfile
ADD Gemfile.lock /var/task/Gemfile.lock

RUN bundle install --path /var/task/vendor/bundle --clean

这将构建您的映像，然后运行它以生成PG和MYSQL可执行文件，然后将其复制到您的lib文件夹。

build.是

#!/bin/bash -x
set -e

rm -rf lib && rm -rf vendor && mkdir lib && mkdir vendor

docker build -t pg_mysql_layer -f Dockerfile .

CONTAINER=$(docker run -d pg_mysql_layer false)

docker cp \
    $CONTAINER:/var/task/vendor/ \
    ./

docker cp \
    $CONTAINER:/usr/lib64/libpq.so.5.5 \
    lib/libpq.so.5

docker cp \
    $CONTAINER:/usr/lib64/mysql/. \
    lib/

docker rm $CONTAINER

在运行./build.sh之后，它将生成所有你需要的文件夹lib和vendor，现在你只需要部署你的lambda函数。

要在本地测试，您可以运行：docker run --rm -it -v $PWD:/var/task -w /var/task lambci/lambda:ruby2.5 handler.run

它将返回类似于此的东西：

REF：https://www.stevenringo.com/ruby-in-aws-lambda-with-postgresql-nokogiri/

REF：https://www.reddit.com/r/ruby/comments/a3e7a1/postgresql_on_aws_lambda_ruby/