gv.rake

namespace :schema do

  desc "Update doc/schema.dot with database schema"
  task :gv => :environment do
    @tables = []

    Rails.configuration.paths.app.models.paths.each do |path|
      Dir[File.join(path, '*.rb')].each do |f|

        klass = File.basename(f, '.*').camelize.constantize

        if klass < ActiveRecord::Base
          begin
            klass.columns
          rescue Exception => ex
            # skip
            next
          end

          @tables << klass if klass < ActiveRecord::Base
        end
      end
    end

    data = Erubis::Eruby.new(TEMPLATE).result(binding())

    File.open('doc/schema.dot', 'w') do |f|
      f.write(data)
    end

  end

  desc "Create a png of the database schema"
  task :png => :gv do
    `dot -T png -o doc/schema.png doc/schema.dot`
  end

end

TEMPLATE = <<-TEMPLATE
digraph Schema {
  overlap = false
  rankdir = RL
  fontsize=12

  node [
    shape = record
    fontsize=12
  ]

  <% @tables.each do |table| %>
    <%= table %> [
      label = "<%= table %>|\\
      <% table.columns.each do |column| %>
      <%= column.name.to_s %>: <%= column.type.to_s %>\\l\\
      <% end %>
      "
    ];

    <% table.reflect_on_all_associations.select { |a| a.macro == :belongs_to }.map(&:class_name).uniq.each do |r| %>
    <%= table %> -> <%= r %>;
    <% end %>

    <% table.reflect_on_all_associations.select { |a| a.macro == :has_and_belongs_to_many }.map(&:class_name).uniq.each do |r| %>
    <%= table %> -> <%= r %> [dir=both];
    <% end %>

  <% end %>
}
TEMPLATE

schema.dot.txt

digraph Schema {
  overlap = false
  rankdir = RL
  fontsize=12

  node [
    shape = record
    fontsize=12
  ]

    Account [
      label = "Account|\
      id: integer\l\
      login: string\l\
      des_crypted_password: string\l\
      firstname: string\l\
      lastname: string\l\
      crypted_password: string\l\
      salt: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      last_login_at: datetime\l\
      hex_md5_of_login_realm_password: string\l\
      uuid: string\l\
      timezone: string\l\
      preferred_client_id: integer\l\
      "
    ];

    Account -> Client;


    Address [
      label = "Address|\
      id: integer\l\
      account_id: integer\l\
      name: string\l\
      delivery_method: string\l\
      identifier: string\l\
      uuid: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      deleted_at: datetime\l\
      "
    ];

    Address -> Account;


    Agent [
      label = "Agent|\
      id: integer\l\
      uuid: string\l\
      account_id: integer\l\
      client_id: integer\l\
      host_id: integer\l\
      configuration_href: string\l\
      notes: text\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      "
    ];

    Agent -> Client;
    Agent -> Account;
    Agent -> Host;


    Client [
      label = "Client|\
      id: integer\l\
      active: integer\l\
      name: string\l\
      longname: string\l\
      parent_id: integer\l\
      reseller: boolean\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      uuid: string\l\
      "
    ];

    Client -> Client;


    EncryptionKey [
      label = "EncryptionKey|\
      id: integer\l\
      private_key_pem: string\l\
      slug: string\l\
      public_key_pem: string\l\
      "
    ];



    Host [
      label = "Host|\
      id: integer\l\
      client_id: integer\l\
      hostname: string\l\
      active: integer\l\
      comments: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      uuid: string\l\
      "
    ];

    Host -> Client;


    HostTag [
      label = "HostTag|\
      id: integer\l\
      name: string\l\
      "
    ];



    HostTagging [
      label = "HostTagging|\
      id: integer\l\
      host_id: integer\l\
      host_tag_id: integer\l\
      "
    ];

    HostTagging -> Host;
    HostTagging -> HostTag;


    Metric [
      label = "Metric|\
      id: integer\l\
      host_id: integer\l\
      metric_type_id: integer\l\
      created_at: datetime\l\
      uuid: string\l\
      "
    ];

    Metric -> MetricType;
    Metric -> Host;


    MetricFilter [
      label = "MetricFilter|\
      id: integer\l\
      any_or_all: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      client_id: integer\l\
      purpose: string\l\
      uuid: string\l\
      deleted_at: datetime\l\
      published_at: datetime\l\
      "
    ];

    MetricFilter -> Client;


    MetricFilterCriterion [
      label = "MetricFilterCriterion|\
      id: integer\l\
      metric_filter_id: integer\l\
      target: string\l\
      comparison: string\l\
      pattern: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      published_at: datetime\l\
      "
    ];

    MetricFilterCriterion -> MetricFilter;


    MetricType [
      label = "MetricType|\
      id: integer\l\
      path: string\l\
      created_at: datetime\l\
      uuid: string\l\
      stereotype: string\l\
      "
    ];



    PasswordToken [
      label = "PasswordToken|\
      id: integer\l\
      account_id: integer\l\
      address_id: integer\l\
      code: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      "
    ];

    PasswordToken -> Address;
    PasswordToken -> Account;


    Privilege [
      label = "Privilege|\
      id: integer\l\
      name: string\l\
      created_at: datetime\l\
      "
    ];


    Privilege -> Role [dir=both];

    Role [
      label = "Role|\
      id: integer\l\
      slug: string\l\
      name: string\l\
      client_id: integer\l\
      uuid: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      "
    ];

    Role -> Client;
    Role -> Role;

    Role -> Privilege [dir=both];

    RoleAssignment [
      label = "RoleAssignment|\
      id: integer\l\
      account_id: integer\l\
      role_id: integer\l\
      client_id: integer\l\
      deactivated_at: datetime\l\
      created_at: datetime\l\
      "
    ];

    RoleAssignment -> Client;
    RoleAssignment -> Account;
    RoleAssignment -> Role;


    ServiceDescriptor [
      label = "ServiceDescriptor|\
      id: integer\l\
      service_type: string\l\
      href: string\l\
      created_at: datetime\l\
      "
    ];



    UiLink [
      label = "UiLink|\
      id: string\l\
      title: string\l\
      target: string\l\
      category: string\l\
      created_at: datetime\l\
      updated_at: datetime\l\
      "
    ];



}

schema.png