ruby-on-rails - 在开发中连接到 mongolab 的 mongoid.yml 设置

Question

对 Rails 很陌生。

使用 Rails 4.2.3

使用 Mongoid 连接到 Mongolab 数据库(不是本地 mongo 实例)

当应用程序运行时，我在开发环境中遇到以下错误。

Problem:
  No configuration could be found for a session named 'default'.
Summary:
  When attempting to create the new session, Mongoid could not find a session configuration for the name: 'default'. This is necessary in order to know the host, port, and options needed to connect.
Resolution:
  Double check your mongoid.yml to make sure under the sessions key that a configuration exists for 'default'. If you have set the configuration programatically, ensure that 'default' exists in the configuration hash.

使用下面的 mongoid.yml。

development:
  # Configure available database sessions. (required)
sessions:
   default:
      uri: 'mongodb://[username]:[password]@ds043497.mongolab.com:43497/[database]' 
      options: 
        consistency: :strong
        max_retries: 30
        retry_interval: 1
        timeout: 15
test:
  sessions:
    default:
      database: my_pm_app_test
      hosts:
        - localhost:27017
      options:
        read: primary
        # In the test environment we lower the retries and retry interval to
        # low amounts for fast failures.
        max_retries: 1
        retry_interval: 0
production:
  # Configure available database sessions. (required)
sessions:
    default:
      # The standard MongoDB connection URI allows for easy replica set 
      # connection setup. 
      # Use environment variables or a config file to keep your 
      # credentials safe.
       uri: 'mongodb://[username]:[password]@ds043497.mongolab.com:43497/[database]' 

      options: 
        # The default consistency is :eventual, which reads from 
        # secondaries when possible. 
        # Strong forces reads to primary. 
        # We recommend using strong consistency.
        consistency: :strong

        # max_retries specifies the number of times to attempt an 
        # operation before giving up. Default 30 seconds
        max_retries: 30

        # retry_interval specifies the number of seconds to wait before 
        # retrying a single operation. Default 1 second.
        retry_interval: 1

        # The default timeout is 5, which is the time in seconds for an 
        # operation to time out.
        # We recommend 15 because it allows for plenty of time in most 
        # operating environments.
        # Mongoid doubles the configured value (known issue) so 15 
        # results in a timeout of 30s.
        # Note that if you have a long-running query (over 30 seconds), 
        # it will time out.
        # See our example for long-running queries in the blog post 
        # referenced above.
        timeout: 15

        # Set this to ensure that your writes are a round-trip operation
        # and are confirmed by the system. Default (false).
        safe: true

        # refresh_interval specifies the number of seconds to cache information
        # about a node. Default is 300 seconds (5 minutes).
        refresh_interval: 10

如果我使用下面的 yml 连接到我的本地数据库实例，它工作正常

    development:
  # Configure available database sessions. (required)
  sessions:
    # Defines the default session. (required)
    default:
      # Defines the name of the default database that Mongoid can connect to.
      # (required).
      database: my_pm_development
      # Provides the hosts the default session can connect to. Must be an array
      # of host:port pairs. (required)
      hosts:
        - localhost:27017
      options:
        # Change the default write concern. (default = { w: 1 })
        # write:
        # w: 1

        # Change the default consistency model to primary, secondary.
        # 'secondary' will send reads to secondaries, 'primary' sends everything
        # to master. (default: primary)
        # read: secondary_preferred

        # How many times Moped should attempt to retry an operation after
        # failure. (default: The number of nodes in the cluster)
        # max_retries: 20

        # The time in seconds that Moped should wait before retrying an
        # operation on failure. (default: 0.25)
        # retry_interval: 0.25

        # The connection pool size per-node.  This should match or exceed the
        # number of threads for a multi-threaded application. (default: 5)
        # pool_size: 5

        # The time in seconds that Moped should wait for the pool to provide
        # an available connection.  This number should probably remain at the 
        # default, unless for some reason you absolutely need to limit the
        # pool_size, as this wait is only used when the pool is saturated.
        # (default: 0.5)
        # pool_timeout: 0.5

        # The time in seconds before Moped will timeout connection and node
        # operations. (default: 5)
        # timeout: 5

        # The amount of time in seconds between forced refreshes of node 
        # information including the discovery of new peers. (default: 300)
        # refresh_interval: 300

        # The amount of time in seconds that a node will be flagged as down.
        # (default: 30) 
        # down_interval: 30

        # Whether connections should use SSL. (default: nil/false)
        # ssl: false

        # Whether Moped will use the existing seeds/nodes to find other peers.
        # (default: true)
        # auto_discover: true


  # Configure Mongoid specific options. (optional)
  options:
    # Includes the root model name in json serialization. (default: false)
    # include_root_in_json: false

    # Include the _type field in serialization. (default: false)
    # include_type_for_serialization: false

    # Preload all models in development, needed when models use
    # inheritance. (default: false)
    # preload_models: false

    # Protect id and type from mass assignment. (default: true)
    # protect_sensitive_fields: true

    # Raise an error when performing a #find and the document is not found.
    # (default: true)
    # raise_not_found_error: true

    # Raise an error when defining a scope with the same name as an
    # existing method. (default: false)
    # scope_overwrite_exception: false

    # Use Active Support's time zone in conversions. (default: true)
    # use_activesupport_time_zone: true

    # Ensure all times are UTC in the app side. (default: false)
    # use_utc: false
test:
  sessions:
    default:
      database: my_pm_test
      hosts:
        - localhost:27017
      options:
        read: primary
        # In the test environment we lower the retries and retry interval to
        # low amounts for fast failures.
        max_retries: 1
        retry_interval: 0

为什么它抛出 mongoid 在开发中找不到 session 。

谢谢

Answer 1

这是因为 yml 文件中的缩进应该始终是 2 个空格，看起来你有 3 个。

development:
# Configure available database sessions. (required)
  sessions:
    default:
      uri: 'mongodb://[username]:[password]@ds043497.mongolab.com:43497/[database]' 
      options: 
        consistency: :strong
        max_retries: 30
        retry_interval: 1
        timeout: 15
test:
  sessions:
    default:
      database: my_pm_app_test
      hosts:
        - localhost:27017
      options:
        read: primary
        # In the test environment we lower the retries and retry interval to
        # low amounts for fast failures.
        max_retries: 1
        retry_interval: 0
production:
  # Configure available database sessions. (required)
  sessions:
    default:
      # The standard MongoDB connection URI allows for easy replica set 
      # connection setup. 
      # Use environment variables or a config file to keep your 
      # credentials safe.
      uri: 'mongodb://[username]:[password]@ds043497.mongolab.com:43497/[database]' 
      options: 
        # The default consistency is :eventual, which reads from 
        # secondaries when possible. 
        # Strong forces reads to primary. 
        # We recommend using strong consistency.
        consistency: :strong

        # max_retries specifies the number of times to attempt an 
        # operation before giving up. Default 30 seconds
        max_retries: 30

        # retry_interval specifies the number of seconds to wait before 
        # retrying a single operation. Default 1 second.
        retry_interval: 1

        # The default timeout is 5, which is the time in seconds for an 
        # operation to time out.
        # We recommend 15 because it allows for plenty of time in most 
        # operating environments.
        # Mongoid doubles the configured value (known issue) so 15 
        # results in a timeout of 30s.
        # Note that if you have a long-running query (over 30 seconds), 
        # it will time out.
        # See our example for long-running queries in the blog post 
        # referenced above.
        timeout: 15

        # Set this to ensure that your writes are a round-trip operation
        # and are confirmed by the system. Default (false).
        safe: true

        # refresh_interval specifies the number of seconds to cache information
        # about a node. Default is 300 seconds (5 minutes).
        refresh_interval: 10