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dag.go
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dag.go
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package controller
import (
"encoding/json"
"fmt"
"strings"
"github.com/argoproj/argo/errors"
wfv1 "github.com/argoproj/argo/pkg/apis/workflow/v1alpha1"
"github.com/argoproj/argo/workflow/common"
"github.com/valyala/fasttemplate"
)
// dagContext holds context information about this context's DAG
type dagContext struct {
// boundaryName is the node name of the boundary node to this DAG.
// This is used to incorporate into each of the task's node names.
boundaryName string
boundaryID string
// tasks are all the tasks in the template
tasks []wfv1.DAGTask
// visited keeps track of tasks we have already visited during an invocation of executeDAG
// in order to avoid duplicating work
visited map[string]bool
// tmpl is the template spec. it is needed to resolve hard-wired artifacts
tmpl *wfv1.Template
// wf is stored to formulate nodeIDs
wf *wfv1.Workflow
}
func (d *dagContext) getTask(taskName string) *wfv1.DAGTask {
for _, task := range d.tasks {
if task.Name == taskName {
return &task
}
}
panic("target " + taskName + " does not exist")
}
// taskNodeName formulates the nodeName for a dag task
func (d *dagContext) taskNodeName(taskName string) string {
return fmt.Sprintf("%s.%s", d.boundaryName, taskName)
}
// taskNodeID formulates the node ID for a dag task
func (d *dagContext) taskNodeID(taskName string) string {
nodeName := d.taskNodeName(taskName)
return d.wf.NodeID(nodeName)
}
func (d *dagContext) getTaskNode(taskName string) *wfv1.NodeStatus {
nodeID := d.taskNodeID(taskName)
node, ok := d.wf.Status.Nodes[nodeID]
if !ok {
return nil
}
return &node
}
// assessDAGPhase assesses the overall DAG status
func (d *dagContext) assessDAGPhase(targetTasks []string, nodes map[string]wfv1.NodeStatus) wfv1.NodePhase {
var phase wfv1.NodePhase
// First check all our nodes to see if any thing is still running. If any thing is still running
// then the DAG is considered still running (even if there are failures). Remember any failures
for _, node := range nodes {
if node.BoundaryID != d.boundaryID {
continue
}
if !node.Completed() {
return wfv1.NodeRunning
}
if !node.Successful() && phase == "" {
phase = node.Phase
}
}
// If we get here, then there are no running tasks. Propagate the failure/error if one was found
if phase != "" {
return phase
}
// There are no currently running tasks. Now check if our dependencies were met
for _, depName := range targetTasks {
depNode := d.getTaskNode(depName)
if depNode == nil {
return wfv1.NodeRunning
}
if !depNode.Successful() {
// we should theoretically never get here since it would have been caught in first loop
return depNode.Phase
}
}
// If we get here, all our dependencies were completed and successful
return wfv1.NodeSucceeded
}
func (woc *wfOperationCtx) executeDAG(nodeName string, tmpl *wfv1.Template, boundaryID string) *wfv1.NodeStatus {
node := woc.getNodeByName(nodeName)
if node != nil && node.Completed() {
return node
}
defer func() {
if node != nil && woc.wf.Status.Nodes[node.ID].Completed() {
_ = woc.killDeamonedChildren(node.ID)
}
}()
dagCtx := &dagContext{
boundaryName: nodeName,
boundaryID: woc.wf.NodeID(nodeName),
tasks: tmpl.DAG.Tasks,
visited: make(map[string]bool),
tmpl: tmpl,
wf: woc.wf,
}
var targetTasks []string
if tmpl.DAG.Targets == "" {
targetTasks = findLeafTaskNames(tmpl.DAG.Tasks)
} else {
targetTasks = strings.Split(tmpl.DAG.Targets, " ")
}
if node == nil {
node = woc.initializeNode(nodeName, wfv1.NodeTypeDAG, tmpl.Name, boundaryID, wfv1.NodeRunning)
rootTasks := findRootTaskNames(dagCtx, targetTasks)
woc.log.Infof("Root tasks of %s identified as %s", nodeName, rootTasks)
for _, rootTaskName := range rootTasks {
woc.addChildNode(node.Name, dagCtx.taskNodeName(rootTaskName))
}
}
// kick off execution of each target task asynchronously
for _, taskNames := range targetTasks {
woc.executeDAGTask(dagCtx, taskNames)
}
// check if we are still running any tasks in this dag and return early if we do
dagPhase := dagCtx.assessDAGPhase(targetTasks, woc.wf.Status.Nodes)
switch dagPhase {
case wfv1.NodeRunning:
return node
case wfv1.NodeError, wfv1.NodeFailed:
return woc.markNodePhase(nodeName, dagPhase)
}
// set outputs from tasks in order for DAG templates to support outputs
scope := wfScope{
tmpl: tmpl,
scope: make(map[string]interface{}),
}
for _, task := range tmpl.DAG.Tasks {
woc.processNodeOutputs(&scope, fmt.Sprintf("tasks.%s", task.Name), dagCtx.getTaskNode(task.Name))
}
outputs, err := getTemplateOutputsFromScope(tmpl, &scope)
if err != nil {
return woc.markNodeError(nodeName, err)
}
if outputs != nil {
node = woc.getNodeByName(nodeName)
node.Outputs = outputs
woc.wf.Status.Nodes[node.ID] = *node
}
// set the outbound nodes from the target tasks
node = woc.getNodeByName(nodeName)
outbound := make([]string, 0)
for _, depName := range targetTasks {
depNode := dagCtx.getTaskNode(depName)
if depNode == nil {
woc.log.Println(depName)
}
outboundNodeIDs := woc.getOutboundNodes(depNode.ID)
for _, outNodeID := range outboundNodeIDs {
outbound = append(outbound, outNodeID)
}
}
woc.log.Infof("Outbound nodes of %s set to %s", node.ID, outbound)
node.OutboundNodes = outbound
woc.wf.Status.Nodes[node.ID] = *node
return woc.markNodePhase(nodeName, wfv1.NodeSucceeded)
}
// findRootTaskNames finds the names of all tasks which have no dependencies.
// Once identified, these root tasks are marked as children to the encompassing node.
func findRootTaskNames(dagCtx *dagContext, targetTasks []string) []string {
//rootTaskNames := make(map[string]bool)
rootTaskNames := make([]string, 0)
visited := make(map[string]bool)
var findRootHelper func(s string)
findRootHelper = func(taskName string) {
if _, ok := visited[taskName]; ok {
return
}
visited[taskName] = true
task := dagCtx.getTask(taskName)
if len(task.Dependencies) == 0 {
rootTaskNames = append(rootTaskNames, taskName)
return
}
for _, depName := range task.Dependencies {
findRootHelper(depName)
}
}
for _, targetTaskName := range targetTasks {
findRootHelper(targetTaskName)
}
return rootTaskNames
}
// executeDAGTask traverses and executes the upward chain of dependencies of a task
func (woc *wfOperationCtx) executeDAGTask(dagCtx *dagContext, taskName string) {
if _, ok := dagCtx.visited[taskName]; ok {
return
}
dagCtx.visited[taskName] = true
node := dagCtx.getTaskNode(taskName)
if node != nil && node.Completed() {
return
}
// Check if our dependencies completed. If not, recurse our parents executing them if necessary
task := dagCtx.getTask(taskName)
dependenciesCompleted := true
dependenciesSuccessful := true
nodeName := dagCtx.taskNodeName(taskName)
for _, depName := range task.Dependencies {
depNode := dagCtx.getTaskNode(depName)
if depNode != nil {
if depNode.Completed() {
if !depNode.Successful() {
dependenciesSuccessful = false
}
continue
}
}
dependenciesCompleted = false
dependenciesSuccessful = false
// recurse our dependency
woc.executeDAGTask(dagCtx, depName)
}
if !dependenciesCompleted {
return
}
if !dependenciesSuccessful {
// TODO: in the future we may support some more sophisticated syntax for deciding on how
// to proceed if at least one dependency succeeded, analogous to airflow's trigger rules,
// (e.g. one_success, all_done, one_failed, etc...). This decision would be made here.
return
}
// All our dependencies completed. Now add the child relationship from our dependency's
// outbound nodes to this node.
node = dagCtx.getTaskNode(taskName)
if node == nil {
woc.log.Infof("All of node %s dependencies %s completed", nodeName, task.Dependencies)
// Add all outbound nodes of our dependencies as parents to this node
for _, depName := range task.Dependencies {
depNode := dagCtx.getTaskNode(depName)
woc.log.Infof("node %s outbound nodes: %s", depNode, depNode.OutboundNodes)
if depNode.Type == wfv1.NodeTypePod {
woc.addChildNode(depNode.Name, nodeName)
} else {
for _, outNodeID := range depNode.OutboundNodes {
woc.addChildNode(woc.wf.Status.Nodes[outNodeID].Name, nodeName)
}
}
}
}
// All our dependencies were satisfied and successful. It's our turn to run
// Substitute params/artifacts from our dependencies and execute the template
newTask, err := woc.resolveDependencyReferences(dagCtx, task)
if err != nil {
woc.initializeNode(nodeName, wfv1.NodeTypeSkipped, task.Template, dagCtx.boundaryID, wfv1.NodeError, err.Error())
return
}
_, _ = woc.executeTemplate(newTask.Template, newTask.Arguments, nodeName, dagCtx.boundaryID)
}
// resolveDependencyReferences replaces any references to outputs of task dependencies, or artifacts in the inputs
// NOTE: by now, input parameters should have been substituted throughout the template
func (woc *wfOperationCtx) resolveDependencyReferences(dagCtx *dagContext, task *wfv1.DAGTask) (*wfv1.DAGTask, error) {
// build up the scope
scope := wfScope{
tmpl: dagCtx.tmpl,
scope: make(map[string]interface{}),
}
ancestors := common.GetTaskAncestry(task.Name, dagCtx.tasks)
for _, ancestor := range ancestors {
ancestorNode := dagCtx.getTaskNode(ancestor)
prefix := fmt.Sprintf("tasks.%s", ancestor)
woc.processNodeOutputs(&scope, prefix, ancestorNode)
}
// Perform replacement
taskBytes, err := json.Marshal(task)
if err != nil {
return nil, errors.InternalWrapError(err)
}
fstTmpl := fasttemplate.New(string(taskBytes), "{{", "}}")
newTaskStr, err := common.Replace(fstTmpl, scope.replaceMap(), true)
if err != nil {
return nil, err
}
var newTask wfv1.DAGTask
err = json.Unmarshal([]byte(newTaskStr), &newTask)
if err != nil {
return nil, errors.InternalWrapError(err)
}
// replace all artifact references
for j, art := range newTask.Arguments.Artifacts {
if art.From == "" {
continue
}
resolvedArt, err := scope.resolveArtifact(art.From)
if err != nil {
return nil, err
}
resolvedArt.Name = art.Name
newTask.Arguments.Artifacts[j] = *resolvedArt
}
return &newTask, nil
}
// findLeafTaskNames finds the names of all tasks whom no other nodes depend on.
// This list of tasks is used as the the default list of targets when dag.targets is omitted.
func findLeafTaskNames(tasks []wfv1.DAGTask) []string {
taskIsLeaf := make(map[string]bool)
for _, task := range tasks {
if _, ok := taskIsLeaf[task.Name]; !ok {
taskIsLeaf[task.Name] = true
}
for _, dependency := range task.Dependencies {
taskIsLeaf[dependency] = false
}
}
leafTaskNames := make([]string, 0)
for taskName, isLeaf := range taskIsLeaf {
if isLeaf {
leafTaskNames = append(leafTaskNames, taskName)
}
}
return leafTaskNames
}