public static async Task <DependencyFlowGraph> BuildAsync(
List <DefaultChannel> defaultChannels,
List <Subscription> subscriptions,
IRemote barOnlyRemote,
int days)
{
// Dictionary of nodes. Key is the repo+branch
Dictionary <string, DependencyFlowNode> nodes = new Dictionary <string, DependencyFlowNode>(
StringComparer.OrdinalIgnoreCase);
List <DependencyFlowEdge> edges = new List <DependencyFlowEdge>();
// First create all the channel nodes. There may be disconnected
// nodes in the graph, so we must process all channels and all subscriptions
foreach (DefaultChannel channel in defaultChannels)
{
DependencyFlowNode flowNode = GetOrCreateNode(channel.Repository, channel.Branch, nodes);
// Add the build times
if (channel.Id != default(int))
{
BuildTime buildTime = await barOnlyRemote.GetBuildTimeAsync(channel.Id, days);
flowNode.OfficialBuildTime = buildTime.OfficialBuildTime ?? 0;
flowNode.PrBuildTime = buildTime.PrBuildTime ?? 0;
flowNode.GoalTimeInMinutes = buildTime.GoalTimeInMinutes ?? 0;
}
else
{
flowNode.OfficialBuildTime = 0;
flowNode.PrBuildTime = 0;
}
// Add a the output mapping.
flowNode.OutputChannels.Add(channel.Channel.Name);
}
// Process all subscriptions (edges)
foreach (Subscription subscription in subscriptions)
{
// Get the target of the subscription
DependencyFlowNode destinationNode = GetOrCreateNode(subscription.TargetRepository, subscription.TargetBranch, nodes);
// Add the input channel for the node
destinationNode.InputChannels.Add(subscription.Channel.Name);
// Find all input nodes by looking up the default channels of the subscription input channel and repository.
// This may return no nodes if there is no default channel for the inputs.
IEnumerable <DefaultChannel> inputDefaultChannels = defaultChannels.Where(d => d.Channel.Name == subscription.Channel.Name &&
d.Repository.Equals(subscription.SourceRepository, StringComparison.OrdinalIgnoreCase));
foreach (DefaultChannel defaultChannel in inputDefaultChannels)
{
DependencyFlowNode sourceNode = GetOrCreateNode(defaultChannel.Repository, defaultChannel.Branch, nodes);
DependencyFlowEdge newEdge = new DependencyFlowEdge(sourceNode, destinationNode, subscription);
destinationNode.IncomingEdges.Add(newEdge);
sourceNode.OutgoingEdges.Add(newEdge);
edges.Add(newEdge);
}
}
return(new DependencyFlowGraph(nodes.Select(kv => kv.Value).ToList(), edges));
}
public void RemoveEdge(DependencyFlowEdge edge)
{
if (Edges.Remove(edge))
{
edge.From.OutgoingEdges.Remove(edge);
DependencyFlowNode targetNode = edge.To;
edge.To.IncomingEdges.Remove(edge);
RecalculateInputChannels(targetNode);
}
}
/// <summary>
/// If pruning the graph is desired, determine whether an edge is interesting
/// </summary>
/// <param name="edge">Edge</param>
/// <returns>True if the edge is interesting, false otherwise.</returns>
public static bool IsInterestingEdge(DependencyFlowEdge edge, bool includeDisabledSubscriptions, IEnumerable <string> includedFrequencies)
{
if (!includeDisabledSubscriptions && !edge.Subscription.Enabled)
{
return(false);
}
if (!includedFrequencies.Any(s => s.Equals(edge.Subscription.Policy.UpdateFrequency.ToString(), StringComparison.OrdinalIgnoreCase)))
{
return(false);
}
return(true);
}
private void MarkLongestPath(DependencyFlowNode node)
{
// The edges we are interested in are those that haven't been marked as on the longest build path
// and aren't back edges, both of which indicate a cycle
var edgesOfInterest = node.OutgoingEdges.Where(e => !e.OnLongestBuildPath && !e.BackEdge).ToList();
if (edgesOfInterest.Count > 0)
{
DependencyFlowEdge pathEdge = edgesOfInterest.Aggregate((e1, e2) => e1.To.BestCasePathTime > e2.To.BestCasePathTime ? e1: e2);
// Mark the edge and the node as on the longest build path
pathEdge.OnLongestBuildPath = true;
pathEdge.To.OnLongestBuildPath = true;
MarkLongestPath(pathEdge.To);
}
}
/// <summary>
/// Mark the back edges of the graph so that they can be ignored when walking it.
/// Determine the backedges by computing dominators for each node. A node n is said to
/// dominate another node if every path from the start to the other node must go through
/// n.
/// </summary>
public void MarkBackEdges()
{
// In this, we will interpret the root of the graph as those nodes that have no outgoing edges
// (call them 'products'). Connect all of these via a start node.
// Add a start node to the graph (a node that connects all nodes that have no outgoing edges
// We will also reverse the graph by flipping the interpretation of incoming and outgoing.
DependencyFlowNode startNode = new DependencyFlowNode("start", "start", "start");
foreach (DependencyFlowNode node in Nodes)
{
if (!node.OutgoingEdges.Any())
{
DependencyFlowEdge newEdge = new DependencyFlowEdge(node, startNode, null);
startNode.IncomingEdges.Add(newEdge);
node.OutgoingEdges.Add(newEdge);
}
}
Nodes.Add(startNode);
// Dominator set for each node starts with the full set of nodes.
Dictionary <DependencyFlowNode, HashSet <DependencyFlowNode> > dominators = new Dictionary <DependencyFlowNode, HashSet <DependencyFlowNode> >();
foreach (DependencyFlowNode node in Nodes)
{
dominators.Add(node, new HashSet <DependencyFlowNode>(Nodes));
}
Queue <DependencyFlowNode> workList = new Queue <DependencyFlowNode>();
workList.Enqueue(startNode);
while (workList.Count != 0)
{
DependencyFlowNode currentNode = workList.Dequeue();
// Compute a new dominator set for this node. Remember we are
// flipping the interepretation of incoming and outgoing
HashSet <DependencyFlowNode> newDom = null;
IEnumerable <DependencyFlowNode> predecessors = currentNode.OutgoingEdges.Select(e => e.To);
IEnumerable <DependencyFlowNode> successors = currentNode.IncomingEdges.Select(e => e.From);
// Compute the intersection of the dominators for the predecessors
foreach (DependencyFlowNode predNode in predecessors)
{
if (newDom == null)
{
newDom = new HashSet <DependencyFlowNode>(dominators[predNode]);
}
else
{
newDom.IntersectWith(dominators[predNode]);
}
}
if (newDom == null)
{
newDom = new HashSet <DependencyFlowNode>();
}
// Add the current node
newDom.Add(currentNode);
// Compare to the existing dominator set for this node
if (!dominators[currentNode].SetEquals(newDom))
{
dominators[currentNode] = newDom;
// Queue all of the successors
foreach (DependencyFlowNode succ in successors)
{
workList.Enqueue(succ);
}
}
}
// Determine backedges
List <DependencyFlowEdge> toRemove = new List <DependencyFlowEdge>();
foreach (DependencyFlowEdge edge in Edges)
{
if (dominators[edge.To].Contains(edge.From))
{
edge.BackEdge = true;
}
}
// Remove the start node we created and links to it
foreach (DependencyFlowEdge edge in startNode.IncomingEdges)
{
RemoveEdge(edge);
}
RemoveNode(startNode);
}
