chef-shell

chef > ::File.exists?(node['c_elk']['logstash']['extra_conf_dir']+'/server.crt')
 => true
chef > ssl_defaults = node['c_elk']['logstash']['ssl_subj_defaults']
 => {"C"=>"CA", "ST"=>"BC", "L"=>"City", "O"=>"Company", "OU"=>"IT", "emailAddress"=>"servers@company.com"}
chef > ssl_subject = sprintf('/C=%s/ST=%s/L=%s/O=%s/OU=%s/CN=%s/emailAddress=%s',
chef >     ssl_defaults['C'], ssl_defaults['ST'], ssl_defaults['L'],
chef >     ssl_defaults['O'], ssl_defaults['OU'], node['fqdn'], ssl_defaults['emailAddress']
chef ?> )
 => "/C=CA/ST=BC/L=City/O=Company/OU=IT/CN=chef-ls-test-01.iad.company.com/emailAddress=servers@company.com"
chef > ssl_subject == `openssl x509 -in #{node['c_elk']['logstash']['extra_conf_dir']}/server.crt -noout -subject | cut -d " " -f 2-`.strip
 => true

recipe_fragment

    not_if {
        # skip cert generation if the cert exists and the subject match
        if ::File.exists?(node['c_elk']['logstash']['extra_conf_dir']+'/server.crt')
            if ssl_subject == `openssl x509 -in #{node['c_elk']['logstash']['extra_conf_dir']}/server.crt -noout -subject | cut -d " " -f 2-`.strip
                true
            end
        end
        false
    }