aws-sdk-core/xml/parser.rb:74:in `set_default_engine': Unable to find a compatible xml library), Ruby version 3.0.2

Question

I am having a legacy ruby daemon script that runs on a linux server. On upgrading all ruby and gem package versions with in the instance, the daemon script is now erroring out. Same error I am getting with in irb

**

/home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core/xml/parser.rb:74:in `set_default_engine': Unable to find a compatible xml library. Ensure that you have installed or added to your Gemfile one of ox, oga, libxml, nokogiri or rexml (RuntimeError)
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core/xml/parser.rb:96:in `<class:Parser>'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core/xml/parser.rb:7:in `<module:Xml>'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core/xml/parser.rb:5:in `<module:Aws>'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core/xml/parser.rb:3:in `<top (required)>'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core/xml.rb:8:in `require_relative'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core/xml.rb:8:in `<top (required)>'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core.rb:68:in `require_relative'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-core-3.121.0/lib/aws-sdk-core.rb:68:in `<top (required)>'
    from <internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:85:in `require'
    from <internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:85:in `require'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-kms-1.48.0/lib/aws-sdk-kms.rb:11:in `<top (required)>'
    from <internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:85:in `require'
    from <internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:85:in `require'
    from /home/ec2-user/.local/share/gem/ruby/gems/aws-sdk-s3-1.102.0/lib/aws-sdk-s3.rb:11:in `<top (required)>'
    from <internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:160:in `require'
    from <internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:160:in `rescue in require'
    ... 5 levels...
<internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:85:in `require': cannot load such file -- aws-sdk-s3 (LoadError)
    from <internal:/usr/share/rubygems/rubygems/core_ext/kernel_require.rb>:85:in `require'
    from (irb):1:in `<main>'
    from /usr/share/gems/gems/irb-1.3.5/exe/irb:11:in `<top (required)>'
    from /usr/bin/irb:23:in `load'
    from /usr/bin/irb:23:in `<main>'

**

aws-sdk-core version : 3.121.0

output for gem list

**

*** LOCAL GEMS ***
abbrev (default: 0.1.0)
aws-eventstream (1.2.0)
aws-partitions (1.501.0)
aws-sdk-core (3.121.0)
aws-sdk-kms (1.48.0)
aws-sdk-s3 (1.102.0)
aws-sdk-sqs (1.44.0)
aws-sigv4 (1.4.0)
base64 (default: 0.1.0)
benchmark (default: 0.1.1)
bigdecimal (3.0.0)
bundler (2.2.22)
cgi (default: 0.2.0)
csv (default: 3.1.9)
daemons (1.4.1)
date (default: 3.1.0)
dbm (default: 1.1.0)
debug (default: 0.1.0)
delegate (default: 0.2.0)
did_you_mean (default: 1.5.0)
digest (default: 3.0.0)
drb (default: 2.0.4)
english (default: 0.7.1)
erb (default: 2.2.0)
etc (default: 1.2.0)
fcntl (default: 1.0.0)
fiddle (default: 1.0.6)
fileutils (default: 1.5.0)
find (default: 0.1.0)
forwardable (default: 1.3.2)
gdbm (default: 2.1.0)
getoptlong (default: 0.1.1)
io-console (0.5.7)
io-nonblock (default: 0.1.0)
io-wait (default: 0.1.0)
ipaddr (default: 1.2.2)
irb (1.3.5)
jmespath (1.4.0)
json (2.5.1)
logger (default: 1.4.3)
matrix (default: 0.3.1)
mutex_m (default: 0.1.1)
net-ftp (default: 0.1.2)
net-http (default: 0.1.1)
net-imap (default: 0.1.1)
net-pop (default: 0.1.1)
net-protocol (default: 0.1.0)
net-smtp (default: 0.2.1)
nkf (default: 0.1.0)
observer (default: 0.1.1)
open-uri (default: 0.1.0)
open3 (default: 0.1.1)
openssl (default: 2.2.0)
optparse (default: 0.1.0)
ostruct (default: 0.3.1)
pathname (default: 0.1.0)
pp (default: 0.1.0)
prettyprint (default: 0.1.0)
prime (default: 0.1.2)
pstore (default: 0.1.1)
psych (3.3.0)
racc (default: 1.5.1)
rake (13.0.3)
rdoc (6.3.1)
readline (default: 0.0.2)
readline-ext (default: 0.1.1)
reline (default: 0.2.5)
resolv (default: 0.2.0)
resolv-replace (default: 0.1.0)
rinda (default: 0.1.0)
rubysl-securerandom (2.0.0)
securerandom (default: 0.1.0)
set (default: 1.0.1)
shellwords (default: 0.1.0)
singleton (default: 0.1.1)
stringio (default: 3.0.0)
strscan (default: 3.0.0)
syslog (default: 0.1.0)
tempfile (default: 0.1.1)
time (default: 0.1.0)
timeout (default: 0.1.1)
tmpdir (default: 0.1.2)
tracer (default: 0.1.1)
tsort (default: 0.1.0)
un (default: 0.1.0)
uri (default: 0.10.1)
weakref (default: 0.1.1)
yaml (default: 0.1.1)
zlib (default: 1.1.0)

**

output for gem env

**

RubyGems Environment:
  - RUBYGEMS VERSION: 3.2.22
  - RUBY VERSION: 3.0.2 (2021-07-07 patchlevel 107) [x86_64-linux]
  - INSTALLATION DIRECTORY: /usr/share/gems
  - USER INSTALLATION DIRECTORY: /home/ec2-user/.local/share/gem/ruby
  - RUBY EXECUTABLE: /usr/bin/ruby
  - GIT EXECUTABLE: 
  - EXECUTABLE DIRECTORY: /usr/bin
  - SPEC CACHE DIRECTORY: /home/ec2-user/.local/share/gem/specs
  - SYSTEM CONFIGURATION DIRECTORY: /etc
  - RUBYGEMS PLATFORMS:
     - ruby
     - x86_64-linux
  - GEM PATHS:
     - /usr/share/gems
     - /home/ec2-user/.local/share/gem/ruby
     - /usr/local/share/gems
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
     - "gem" => "--user-install --bindir /home/ec2-user/bin"
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /usr/local/bin
     - /usr/bin
     - /usr/local/sbin
     - /usr/sbin
     - /home/ec2-user/.local/bin
     - /home/ec2-user/bin

**

Any help would really be appreciated.

Answer 1

The issue got resolved after installing few dependency packages

yum -y install gcc mysql-devel ruby-devel rubygems

and then installing nokogiri worked fine

Answer 2

In my case, I just did gem install nokogiri and it is working here.

Perhaps the context/env your daemon script gets is different than running locally, though I'm surprised irb gives the same issue in that case.

Answer 3

For people checking this thread in future, rexml was moved from default to bundled gems in ruby 3.0.0. If aws-sdk-core was working for you before update to ruby 3, all you need to do is add rexml to your gemfile. Of course previous answers will work, as mentioned in error message any xml library is fine.

Answer 4

Step1: add this to your Gemfile > gem "nokogiri", force_ruby_platform: true

Step2: add this to your .rb file > require 'nokogiri'

Step3: bundle install

Step4: bundle exec ruby filename.rb

This worked for me.