Class: StackBuilder::Stack::Stack

Inherits:
Object
  • Object
show all
Defined in:
lib/stackbuilder/stack/stack.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(provider, stack_file, id = nil, overrides = nil) ⇒ Stack

Returns a new instance of Stack.

Raises:

  • (InvalidArgs) 


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# File 'lib/stackbuilder/stack/stack.rb', line 13

def initialize(provider, stack_file, id = nil, overrides = nil)

    StackBuilder::Common::Config.set_silent
    @logger = StackBuilder::Common::Config.logger

    raise InvalidArgs, "Node provider is not derived from
        StackBuilder::Stack::NodeProvider." unless provider.is_a?(NodeProvider)

    @provider = provider

    env_vars = provider.get_env_vars
    stack = StackBuilder::Common.load_yaml(stack_file, env_vars)
    merge_maps( stack, overrides.end_with?('.json') ?
        JSON.load(File.new(overrides, 'r')) : JSON.load(overrides) ) \
        unless overrides.nil?

    @logger.debug("Initializing stack definition:\n #{stack.to_yaml}")

    if id.nil?
        @id = SecureRandom.uuid.gsub(/-/, '')
        @provider.set_stack(stack, @id)
    else
        @id = id
        @provider.set_stack(stack, @id)
    end

    @name = stack["name"]
    @nodes = { }

    if stack.has_key?("stack") && stack["stack"].is_a?(Array)
        
        stack["stack"].each do |n|
            
            raise ArgumentError, "Node does not have a 'node' attribute " +
                "that identifies it: #{n}" unless n.has_key?("node")
            
            node_id = n["node"]
            raise ArgumentError, "Node identified by \"#{node_id}\" " +
                "already exists." if @nodes.has_key? (node_id)

            n["attributes"] = { } if n["attributes"].nil?
            merge_maps(n["attributes"], stack["attributes"]) unless stack["attributes"].nil?

            node_manager = @provider.get_node_manager(n)
            raise InvalidArgs, "Node task is of an invalid type. It is not derived " +
                "from StackBuilder::Stack::Node." unless node_manager.is_a?(NodeManager)

            @nodes[node_id] = NodeTask.new(node_manager, @nodes, n, id)
        end

        # Associate dependencies
        stack["stack"].each do |n|
            
            node_task = @nodes[n["node"]]
            
            if n.has_key?("depends_on") && n["depends_on"].is_a?(Array)
                
                n["depends_on"].each do |d|
                    
                    raise ArgumentError, "Dependency node \"#{d}\" " +
                        "is not defined." unless @nodes.has_key?(d)
                    
                    node_task.add_dependency(d)
                end
            end

            if n.has_key?("targets") && n["targets"].is_a?(Array)

                n["targets"].each do |d|

                    raise ArgumentError, "Target node \"#{d}\" " +
                        "is not defined." unless @nodes.has_key?(d)

                    node_task.add_dependency(d, true)
                end
            end

            node_task.process_attribute_dependencies
        end
        
    else
        raise ArgumentError, "System needs to have at least one node defined."
    end
end

Instance Attribute Details

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/stackbuilder/stack/stack.rb', line 9

def id
  @id
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/stackbuilder/stack/stack.rb', line 10

def name
  @name
end

#nodes ⇒ Object (readonly)

Returns the value of attribute nodes.



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# File 'lib/stackbuilder/stack/stack.rb', line 11

def nodes
  @nodes
end

Instance Method Details

#destroy ⇒ Object 



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# File 'lib/stackbuilder/stack/stack.rb', line 201

def destroy

    @nodes.values.each { |n| n.deleted = true }
    
    begin
        destroy_events = Set.new([ "stop", "uninstall" ])
        self.orchestrate(destroy_events)
    rescue Exception => msg
        @logger.warn("An error was encountered attempting to do an orderly tear down of the system: #{msg}")
        @logger.info("All remaining nodes will be destroyed forcefully.")
    end
    
    threads = [ ]
    
    @nodes.values.each do |n|
        (n.manager.get_scale - 1).downto(0) do |i|
            threads << Thread.new {

                @logger.debug("Deleted #{n} #{i}.")
                $stdout.printf("Deleting node \"%s\" #%d.\n", n.name, i) unless @logger.debug?
                
                n.manager.delete(i)
            }
        end
    end
    
    threads.each { |t| t.join }
end

#orchestrate(events = nil, name = nil, scale = nil) ⇒ Object

Raises:



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# File 'lib/stackbuilder/stack/stack.rb', line 98

def orchestrate(events = nil, name = nil, scale = nil)

    events = Set.new([ "configure" ]) if events.nil?

    unless name.nil?
        node = @nodes[name]
        raise StackBuilder::Common::StackBuilderError, "Invalid node name \"#{name}'\"." if node.nil?

        unless scale.nil?
            raise ArgumentError, \
                "The scale for node \"#{node.name}\" must be greater than 0." \
                if scale < 1
            raise ArgumentError, \
                "The scale for node \"#{node.name}\" cannot be greater than #{node.max_scale}." \
                if scale > node.max_scale
            
            node.scale = scale
        end
    end

    prep_threads = [ ]
    execution_list = [ ]

    if name.nil?

        @nodes.each_value do |n|
            execution_list << n if n.init_dependency_count == 0
            prep_threads += n.prepare
        end

        task_count = @nodes.size
    else
        # Only process nodes that depend on 'name' and their dependencies

        def add_parent_task(node, prep_threads, nodes_visited)

            prep_threads += node.prepare
            nodes_visited << node.name

            node.init_dependency_count(1)

            node.parent_nodes.each do |n|
                add_parent_task(n, prep_threads, nodes_visited)
            end
        end

        node = @nodes[name]
        nodes_visited = Set.new([ node.name ])

        execution_list << node
        prep_threads += node.prepare

        node.parent_nodes.each do |n|
            add_parent_task(n, prep_threads, nodes_visited)
        end

        task_count = nodes_visited.size
    end

    execution_count = 0
    terminate = false
    
    while !terminate && !execution_list.empty? do

        mutex = Mutex.new
        new_execution_list = [ ]
        
        exec_threads = [ ]
        execution_list.each do |n|
            exec_threads << Thread.new {
                begin
                    executable_parents = n.orchestrate(events)
                    
                    mutex.synchronize {
                        new_execution_list |= executable_parents
                        execution_count += 1
                    }                    
                rescue Exception => msg
                    @logger.error("Processing node '#{n}' terminated with an exception: #{msg}")
                    @logger.info(msg.backtrace.join("\n\t"))
                    terminate = true
                end
            }
        end
        exec_threads.each { |t| t.join }

        execution_list = new_execution_list
    end
    
    prep_threads.each { |t| t.join }

    @nodes.each_value do |n|
        n.prev_scale = n.scale
    end

    raise StackBuilder::Common::StackBuilderError, "Processing of stack nodes " +
        "did not complete because of errors." if execution_count < task_count
end

#scale(name, scale) ⇒ Object 



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# File 'lib/stackbuilder/stack/stack.rb', line 197

def scale(name, scale)
    self.orchestrate(nil, name, scale)
end