Class: Build::Graph::Walker
- Inherits:
-
Object
- Object
- Build::Graph::Walker
- Defined in:
- lib/build/graph/walker.rb
Overview
A walker walks over a graph and applies a task to each node.
Instance Attribute Summary collapse
-
#count ⇒ Object
readonly
Returns the value of attribute count.
-
#dirty ⇒ Object
readonly
Returns the value of attribute dirty.
-
#failed_outputs ⇒ Object
readonly
Returns the value of attribute failed_outputs.
-
#failed_tasks ⇒ Object
readonly
Returns the value of attribute failed_tasks.
-
#logger ⇒ Object
readonly
Primarily for debugging from within Task.
-
#monitor ⇒ Object
readonly
Returns the value of attribute monitor.
-
#outputs ⇒ Object
readonly
An Array of transient outputs which are currently being generated.
-
#parents ⇒ Object
readonly
Returns the value of attribute parents.
-
#tasks ⇒ Object
readonly
An Array of all instantiated tasks.
Class Method Summary collapse
Instance Method Summary collapse
- #call(node, parent_task = nil) ⇒ Object
- #clear_failed ⇒ Object
- #delete(node) ⇒ Object
- #enter(task) ⇒ Object
- #exit(task) ⇒ Object
- #failed? ⇒ Boolean
-
#initialize(logger: Console.logger, &block) ⇒ Walker
constructor
A new instance of Walker.
- #run(**options) ⇒ Object
- #update(nodes) ⇒ Object
-
#wait_for_children(parent, children) ⇒ Object
A parent task only completes once all it’s children are complete.
- #wait_on_paths(task, paths) ⇒ Object
Constructor Details
#initialize(logger: Console.logger, &block) ⇒ Walker
Returns a new instance of Walker.
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# File 'lib/build/graph/walker.rb', line 42 def initialize(logger: Console.logger, &block) # Node -> Task mapping. @tasks = {} @update = block # A list of paths which are currently being generated by tasks: @outputs = {} @parents = Hash.new{|h,k| h[k] = []} # Failed output paths: @failed_tasks = [] @failed_outputs = Set.new @logger = logger @monitor = Files::Monitor.new(logger: @logger) end |
Instance Attribute Details
#count ⇒ Object (readonly)
Returns the value of attribute count.
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# File 'lib/build/graph/walker.rb', line 73 def count @count end |
#dirty ⇒ Object (readonly)
Returns the value of attribute dirty.
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# File 'lib/build/graph/walker.rb', line 74 def dirty @dirty end |
#failed_outputs ⇒ Object (readonly)
Returns the value of attribute failed_outputs.
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# File 'lib/build/graph/walker.rb', line 71 def failed_outputs @failed_outputs end |
#failed_tasks ⇒ Object (readonly)
Returns the value of attribute failed_tasks.
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# File 'lib/build/graph/walker.rb', line 70 def failed_tasks @failed_tasks end |
#logger ⇒ Object (readonly)
Primarily for debugging from within Task
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# File 'lib/build/graph/walker.rb', line 62 def logger @logger end |
#monitor ⇒ Object (readonly)
Returns the value of attribute monitor.
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# File 'lib/build/graph/walker.rb', line 78 def monitor @monitor end |
#outputs ⇒ Object (readonly)
An Array of transient outputs which are currently being generated.
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# File 'lib/build/graph/walker.rb', line 68 def outputs @outputs end |
#parents ⇒ Object (readonly)
Returns the value of attribute parents.
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# File 'lib/build/graph/walker.rb', line 76 def parents @parents end |
#tasks ⇒ Object (readonly)
An Array of all instantiated tasks.
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# File 'lib/build/graph/walker.rb', line 65 def tasks @tasks end |
Class Method Details
.for(task_class, *args, **options) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 32 def self.for(task_class, *args, **) self.new(**) do |walker, node, parent_task = nil| task = task_class.new(walker, node, *args) task.visit do task.update end end end |
Instance Method Details
#call(node, parent_task = nil) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 86 def call(node, parent_task = nil) # We try to fetch the task if it has already been invoked, otherwise we create a new task. @tasks.fetch(node) do @logger&.debug(self) {"Update: #{node} #{parent_task.class}"} # This method should add the node @update.call(self, node, parent_task) # This should now be defined: return @tasks[node] end end |
#clear_failed ⇒ Object
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# File 'lib/build/graph/walker.rb', line 224 def clear_failed @failed_tasks.each do |task| self.delete(task.node) end if @failed_tasks @failed_tasks = [] @failed_outputs = Set.new end |
#delete(node) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 216 def delete(node) @logger&.debug(self) {"Delete #{node}"} if task = @tasks.delete(node) @monitor.delete(task) end end |
#enter(task) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 162 def enter(task) @logger&.debug(self) {"Walker entering: #{task.node}"} @tasks[task.node] = task # In order to wait on outputs, they must be known before entering the task. This might seem odd, but unless we know outputs are being generated, waiting for them to complete is impossible - unless this was somehow specified ahead of time. The implications of this logic is that all tasks must be sequential in terms of output -> input chaning. This is by design and is not a problem in practice. if outputs = task.outputs @logger&.debug(self) do |buffer| buffer.puts "Task will generate outputs:" Array(outputs).each do |output| buffer.puts output.inspect end end outputs.each do |path| # Tasks which have children tasks may list the same output twice. This is not a bug. @outputs[path.to_s] ||= [] end end end |
#exit(task) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 184 def exit(task) @logger&.debug(self) {"Walker exiting: #{task.node}, task #{task.failed? ? 'failed' : 'succeeded'}"} # Fail outputs if the node failed: if task.failed? @failed_tasks << task if task.outputs @failed_outputs += task.outputs.collect{|path| path.to_s} end end # Clean the node's outputs: task.outputs.each do |path| path = path.to_s @logger&.debug(self) {"File #{task.failed? ? 'failed' : 'available'}: #{path}"} if edges = @outputs.delete(path) # @logger&.debug "\tUpdating #{edges.count} edges..." edges.each{|edge| edge.traverse(task)} end end # Notify the parent nodes that the child is done: if parents = @parents.delete(task.node) parents.each{|edge| edge.traverse(task)} end @monitor.add(task) end |
#failed? ⇒ Boolean
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# File 'lib/build/graph/walker.rb', line 99 def failed? @failed_tasks.size > 0 end |
#run(**options) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 233 def run(**) yield monitor.run(**) do yield end end |
#update(nodes) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 80 def update(nodes) Array(nodes).each do |node| self.call(node) end end |
#wait_for_children(parent, children) ⇒ Object
A parent task only completes once all it’s children are complete.
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# File 'lib/build/graph/walker.rb', line 136 def wait_for_children(parent, children) # Consider only incomplete/failed children: children = children.select{|child| !child.complete?} # If there are no children like this, then done: return true if children.size == 0 @logger&.debug(self) {"Task #{parent} is waiting on #{children.count} children"} # Otherwise, construct an edge to track state changes: edge = Edge.new children.each do |child| if child.failed? edge.skip!(child) else # We are waiting for this child to finish: edge.increment! @parents[child.node] << edge end end return edge.wait end |
#wait_on_paths(task, paths) ⇒ Object
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# File 'lib/build/graph/walker.rb', line 103 def wait_on_paths(task, paths) # If there are no paths, we are done: return true if paths.count == 0 # We create a new directed hyper-graph edge which waits for all paths to be ready (or failed): edge = Edge.new paths = paths.collect(&:to_s) paths.each do |path| # Is there a task generating this output? if outputs = @outputs[path] @logger&.debug(self) {"Task #{task} is waiting on path #{path}"} # When the output is ready, trigger this edge: outputs << edge edge.increment! elsif !File.exist?(path) @logger&.warn(self) {"Task #{task} is waiting on paths which don't exist and are not being generated!"} raise RuntimeError, "File #{path} is not being generated by any active task!" # What should we do about paths which haven't been registered as outputs? # Either they exist - or they don't. # If they exist, it means they are probably static inputs of the build graph. # If they don't, it might be an error, or it might be deliberate. end end failed = paths.any?{|path| @failed_outputs.include?(path)} return edge.wait && !failed end |