Class: Marloss::Store

Inherits:
Object
  • Object
show all
Defined in:
lib/marloss/store.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table, hash_key, ttl: 30, client_options: {}) ⇒ Store

Returns a new instance of Store.



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# File 'lib/marloss/store.rb', line 8

def initialize(table, hash_key, ttl: 30, client_options: {})
  @client = Aws::DynamoDB::Client.new(client_options)
  @table = table
  @hash_key = hash_key
  @ttl = ttl
end

Instance Attribute Details

#client ⇒ Object (readonly)

Returns the value of attribute client.



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# File 'lib/marloss/store.rb', line 6

def client
  @client
end

#hash_key ⇒ Object (readonly)

Returns the value of attribute hash_key.



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# File 'lib/marloss/store.rb', line 6

def hash_key
  @hash_key
end

#table ⇒ Object (readonly)

Returns the value of attribute table.



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# File 'lib/marloss/store.rb', line 6

def table
  @table
end

#ttl ⇒ Object (readonly)

Returns the value of attribute ttl.



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# File 'lib/marloss/store.rb', line 6

def ttl
  @ttl
end

Instance Method Details

#create_lock(name) ⇒ Object 



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# File 'lib/marloss/store.rb', line 55

def create_lock(name)
  client.put_item(
    table_name: table,
    item: {
      hash_key => name,
      "ProcessID" => process_id,
      "Expires" => (Time.now + ttl).to_i
    },
    expression_attribute_names: {
      "#E" => "Expires",
      "#P" => "ProcessID"
    },
    expression_attribute_values: {
      ":now" => Time.now.to_i,
      ":process_id" => process_id,
    },
    condition_expression: "attribute_not_exists(#{hash_key}) OR #E < :now OR #P = :process_id"
  )

  Marloss.logger.info("Lock for #{name} created successfully, will expire in #{ttl} seconds")
rescue Aws::DynamoDB::Errors::ConditionalCheckFailedException => e

  Marloss.logger.error("Failed to create lock for #{name}")

  raise(LockNotObtainedError, e.message)
end

#create_table ⇒ Object 



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# File 'lib/marloss/store.rb', line 15

def create_table
  client.create_table(
    attribute_definitions: [
      {
        attribute_name: hash_key,
        attribute_type: "S",
      }
    ],
    key_schema: [
      {
        attribute_name: hash_key,
        key_type: "HASH",
      }
    ],
    provisioned_throughput: {
      read_capacity_units: 5,
      write_capacity_units: 5,
    },
    table_name: table
  )

  Marloss.logger.info("DynamoDB table created successfully")

  client.update_time_to_live(
    table_name: table,
    time_to_live_specification: {
      enabled: true,
      attribute_name: "Expires"
    }
  )

  Marloss.logger.info("DynamoDB table TTL configured successfully")
end

#delete_lock(name) ⇒ Object 



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# File 'lib/marloss/store.rb', line 107

def delete_lock(name)
  client.delete_item(key: { hash_key => name }, table_name: table)

  Marloss.logger.info("Lock for #{name} deleted successfully")
end

#delete_table ⇒ Object 



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# File 'lib/marloss/store.rb', line 49

def delete_table
  client.delete_table(table_name: table)

  Marloss.logger.info("DynamoDB table deleted successfully")
end

#refresh_lock(name) ⇒ Object 



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# File 'lib/marloss/store.rb', line 82

def refresh_lock(name)
  client.update_item(
    table_name: table,
    key: { hash_key => name },
    expression_attribute_names: {
      "#E" => "Expires",
      "#P" => "ProcessID"
    },
    expression_attribute_values: {
      ":expires" => (Time.now + ttl).to_i,
      ":now" => Time.now.to_i,
      ":process_id" => process_id,
    },
    update_expression: "SET #E = :expires", 
    condition_expression: "attribute_exists(#{hash_key}) AND (#E < :now OR #P = :process_id)"
  )

  Marloss.logger.info("Lock for #{name} refreshed successfully, will expire in #{ttl} seconds")
rescue Aws::DynamoDB::Errors::ConditionalCheckFailedException => e

  Marloss.logger.error("Failed to refresh lock for #{name}")

  raise(LockNotRefreshedError, e.message)
end