Move cncd/{logging,pubsub,queue}/ to server/{logging,pubsub,queue}/ (#346)

* Move cncd/{logging,pubsub,queue}/ to server/{logging,pubsub,queue}/

* Update REAMDEs and include history

Co-authored-by: Anbraten <anton@ju60.de>

Co-authored-by: Anbraten <anton@ju60.de>

server/queue/queue.go

@@ -0,0 +1,172 @@
+package queue
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+)
+
+var (
+	// ErrCancel indicates the task was cancelled.
+	ErrCancel = errors.New("queue: task cancelled")
+
+	// ErrNotFound indicates the task was not found in the queue.
+	ErrNotFound = errors.New("queue: task not found")
+)
+
+// Task defines a unit of work in the queue.
+type Task struct {
+	// ID identifies this task.
+	ID string `json:"id,omitempty"`
+
+	// Data is the actual data in the entry.
+	Data []byte `json:"data"`
+
+	// Labels represents the key-value pairs the entry is lebeled with.
+	Labels map[string]string `json:"labels,omitempty"`
+
+	// Task IDs this task depend
+	Dependencies []string
+
+	// Dependency's exit status
+	DepStatus map[string]string
+
+	// RunOn failure or success
+	RunOn []string
+}
+
+// ShouldRun tells if a task should be run or skipped, based on dependencies
+func (t *Task) ShouldRun() bool {
+	if runsOnFailure(t.RunOn) && runsOnSuccess(t.RunOn) {
+		return true
+	}
+
+	if !runsOnFailure(t.RunOn) && runsOnSuccess(t.RunOn) {
+		for _, status := range t.DepStatus {
+			if StatusSuccess != status {
+				return false
+			}
+		}
+		return true
+	}
+
+	if runsOnFailure(t.RunOn) && !runsOnSuccess(t.RunOn) {
+		for _, status := range t.DepStatus {
+			if StatusSuccess == status {
+				return false
+			}
+		}
+		return true
+	}
+
+	return false
+}
+
+func (t *Task) String() string {
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("%s (%s) - %s", t.ID, t.Dependencies, t.DepStatus))
+	return sb.String()
+}
+
+func runsOnFailure(runsOn []string) bool {
+	for _, status := range runsOn {
+		if status == "failure" {
+			return true
+		}
+	}
+	return false
+}
+
+func runsOnSuccess(runsOn []string) bool {
+	if len(runsOn) == 0 {
+		return true
+	}
+
+	for _, status := range runsOn {
+		if status == "success" {
+			return true
+		}
+	}
+	return false
+}
+
+// InfoT provides runtime information.
+type InfoT struct {
+	Pending       []*Task `json:"pending"`
+	WaitingOnDeps []*Task `json:"waiting_on_deps"`
+	Running       []*Task `json:"running"`
+	Stats         struct {
+		Workers       int `json:"worker_count"`
+		Pending       int `json:"pending_count"`
+		WaitingOnDeps int `json:"waiting_on_deps_count"`
+		Running       int `json:"running_count"`
+		Complete      int `json:"completed_count"`
+	} `json:"stats"`
+	Paused bool
+}
+
+func (t *InfoT) String() string {
+	var sb strings.Builder
+
+	for _, task := range t.Pending {
+		sb.WriteString("\t" + task.String())
+	}
+
+	for _, task := range t.Running {
+		sb.WriteString("\t" + task.String())
+	}
+
+	for _, task := range t.WaitingOnDeps {
+		sb.WriteString("\t" + task.String())
+	}
+
+	return sb.String()
+}
+
+// Filter filters tasks in the queue. If the Filter returns false,
+// the Task is skipped and not returned to the subscriber.
+type Filter func(*Task) bool
+
+// Queue defines a task queue for scheduling tasks among
+// a pool of workers.
+type Queue interface {
+	// Push pushes a task to the tail of this queue.
+	Push(c context.Context, task *Task) error
+
+	// Push pushes a task to the tail of this queue.
+	PushAtOnce(c context.Context, tasks []*Task) error
+
+	// Poll retrieves and removes a task head of this queue.
+	Poll(c context.Context, f Filter) (*Task, error)
+
+	// Extend extends the deadline for a task.
+	Extend(c context.Context, id string) error
+
+	// Done signals the task is complete.
+	Done(c context.Context, exitStatus string, id string) error
+
+	// Error signals the task is complete with errors.
+	Error(c context.Context, id string, err error) error
+
+	// Error signals the task is complete with errors.
+	ErrorAtOnce(c context.Context, id []string, err error) error
+
+	// Evict removes a pending task from the queue.
+	Evict(c context.Context, id string) error
+
+	// Evict removes a pending task from the queue.
+	EvictAtOnce(c context.Context, id []string) error
+
+	// Wait waits until the task is complete.
+	Wait(c context.Context, id string) error
+
+	// Info returns internal queue information.
+	Info(c context.Context) InfoT
+
+	// Stops the queue from handing out new work items in Poll
+	Pause()
+
+	// Starts the queue again, Poll returns new items
+	Resume()
+}