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system.roles Collection

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The system.roles collection in the admin database stores the user-defined roles. To create and manage these user-defined roles, MongoDB provides role management commands.

system.roles Schema

The documents in the system.roles collection have the following schema:

copy 
{
  _id: <system-defined id>,
  role: "<role name>",
  db: "<database>",
  privileges:
      [
          {
              resource: { <resource> },
              actions: [ "<action>", ... ]
          },
          ...
      ],
  roles:
      [
          { role: "<role name>", db: "<database>" },
          ...
      ]
}

A system.roles document has the following fields:

admin.system.roles.role

The role field is a string that specifies the name of the role.

admin.system.roles.db

The db field is a string that specifies the database to which the role belongs. MongoDB uniquely identifies each role by the pairing of its name (i.e. role) and its database.

admin.system.roles.privileges

The privileges array contains the privilege documents that define the privileges for the role.

A privilege document has the following syntax:

copy 
{
  resource: { <resource> },
  actions: [ "<action>", ... ]
}

Each privilege document has the following fields:

admin.system.roles.privileges[n].resource

A document that specifies the resources upon which the privilege actions apply. The document has one of the following form:

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{ db: <database>, collection: <collection> }

or

copy 
{ cluster : true }

See Resource Document for more details.

admin.system.roles.privileges[n].actions

An array of actions permitted on the resource. For a list of actions, see Privilege Actions.

admin.system.roles.roles

The roles array contains role documents that specify the roles from which this role inherits privileges.

A role document has the following syntax:

copy 
{ role: "<role name>", db: "<database>" }

A role document has the following fields:

admin.system.roles.roles[n].role

The name of the role. A role can be a built-in role provided by MongoDB or a user-defined role.

admin.system.roles.roles[n].db

The name of the database where the role is defined.

Examples

Consider the following sample documents found in system.roles collection of the admin database.

A User-Defined Role Specifies Privileges

The following is a sample document for a user-defined role appUser defined for the myApp database:

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{
  _id: "myApp.appUser",
  role: "appUser",
  db: "myApp",
  privileges: [
       { resource: { db: "myApp" , collection: "" },
         actions: [ "find", "createCollection", "dbStats", "collStats" ] },
       { resource: { db: "myApp", collection: "logs" },
         actions: [ "insert" ] },
       { resource: { db: "myApp", collection: "data" },
         actions: [ "insert", "update", "remove", "compact" ] },
       { resource: { db: "myApp", collection: "system.js" },
         actions: [ "find" ] },
  ],
  roles: []
}

The privileges array lists the five privileges that the appUser role specifies:

  • The first privilege permits its actions ( "find", "createCollection", "dbStats", "collStats") on all the collections in the myApp database excluding its system collections. See Specify a Database as Resource.
  • The next two privileges permits additional actions on specific collections, logs and data, in the myApp database. See Specify a Collection of a Database as Resource.
  • The last privilege permits actions on one system collections in the myApp database. While the first privilege gives database-wide permission for the find action, the action does not apply to myApp’s system collections. To give access to a system collection, a privilege must explicitly specify the collection. See Resource Document.

As indicated by the empty roles array, appUser inherits no additional privileges from other roles.

User-Defined Role Inherits from Other Roles

The following is a sample document for a user-defined role appAdmin defined for the myApp database: The document shows that the appAdmin role specifies privileges as well as inherits privileges from other roles:

copy 
{
  _id: "myApp.appAdmin",
  role: "appAdmin",
  db: "myApp",
  privileges: [
      {
         resource: { db: "myApp", collection: "" },
         actions: [ "insert", "dbStats", "collStats", "compact" ]
      }
  ],
  roles: [
      { role: "appUser", db: "myApp" }
  ]
}

The privileges array lists the privileges that the appAdmin role specifies. This role has a single privilege that permits its actions ( "insert", "dbStats", "collStats", "compact") on all the collections in the myApp database excluding its system collections. See Specify a Database as Resource.

The roles array lists the roles, identified by the role names and databases, from which the role appAdmin inherits privileges.

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