ruby - 如何处理 mongodb 在 ruby​​ 中的 E11000 重复键错误

Question

在ruby中有没有处理mongodb相关异常的好例子？在这种情况下，我有:

/home/askar/.rvm/gems/ruby-1.9.3-p429/gems/mongo-1.8.6/lib/mongo/networking.rb:89:in `send_message_with_gle': 11000: E11000 duplicate key error index: somedb.somecoll.$_id_  dup key: { : "some_id" } (Mongo::OperationFailure)
    from /home/askar/.rvm/gems/ruby-1.9.3-p429/gems/mongo-1.8.6/lib/mongo/collection.rb:1108:in `block in insert_documents'
    from /home/askar/.rvm/gems/ruby-1.9.3-p429/gems/mongo-1.8.6/lib/mongo/util/logging.rb:33:in `block in instrument'
    from /home/askar/.rvm/gems/ruby-1.9.3-p429/gems/mongo-1.8.6/lib/mongo/util/logging.rb:65:in `instrument'
    from /home/askar/.rvm/gems/ruby-1.9.3-p429/gems/mongo-1.8.6/lib/mongo/util/logging.rb:32:in `instrument'
    from /home/askar/.rvm/gems/ruby-1.9.3-p429/gems/mongo-1.8.6/lib/mongo/collection.rb:1106:in `insert_documents'
    from /home/askar/.rvm/gems/ruby-1.9.3-p429/gems/mongo-1.8.6/lib/mongo/collection.rb:375:in `insert'
    from lib/tasks/getorders.rb:47:in `block in <main>'
    from lib/tasks/getorders.rb:25:in `each'
    from lib/tasks/getorders.rb:25:in `<main>'

我遇到这个错误是因为我试图插入一个文档，其 id 已经存在于 mongodb 数据库中，我只想知道如何在 ruby​​ 中处理与 mongodb 相关的异常。例如，如果发生异常，那么我会更改哈希的 id，然后重新尝试插入它。

rescue block 会是什么样子？

Answer 1

ruby block 看起来像这样:

begin
  # your operation
rescue Mongo::OperationFailure => e
  if e.message =~ /^11000/
    puts "Duplicate key error #{$!}"
    # do something to recover from duplicate
  else
    raise e
  end
end
# the rest of the exceptions follow ..
# if you just care about the dup error
# then ignore them
#rescue Mongo::MongoRubyError
#  #Mongo::ConnectionError, Mongo::ConnectionTimeoutError, Mongo::GridError, Mongo::InvalidSortValueError, Mongo::MongoArgumentError, Mongo::NodeWithTagsNotFound
#  puts "Ruby Error :  #{$!}"
#rescue Mongo::MongoDBError
#  # Mongo::AuthenticationError, Mongo::ConnectionFailure, Mongo::InvalidOperation, Mongo::OperationFailure
#  puts "DB Error :  #{$!}"
#rescue Mongo::OperationTimeout
#  puts "Socket operation timeout Error :  #{$!}"
#rescue Mongo::InvalidNSName
#  puts "invalid collection or database Error :  #{$!}"
#end

但是，如果您正在更新一条已经存在的记录，为什么不使用 upsert .

如果您正在创建新记录，那么为什么不让 mongod 创建 _id 呢？