Implement queueing

Pipeline runs belonging to one repository now run sequentially. If a
pipeline run cannot start immediately, it is created as "pending", and a
process is started to periodically check if it can start.

Since the pipeline manager service may be restarted, it check on boot if
there are any pending runs for the repositories under its control and
starts the periodic check for those.

We can improve on the design by adding a signal in the finish task of a
pipeline run that the run will soon finish, reducing the up to 30s wait
time for the next run.

Closes #394.

internal/manager/bitbucket.go

@@ -0,0 +1,102 @@
+package manager
+
+import (
+	"fmt"
+
+	"github.com/opendevstack/pipeline/pkg/bitbucket"
+)
+
+type bitbucketInterface interface {
+	bitbucket.CommitClientInterface
+	bitbucket.RawClientInterface
+	bitbucket.RepoClientInterface
+}
+
+type repository struct {
+	Project struct {
+		Key string `json:"key"`
+	} `json:"project"`
+	Slug string `json:"slug"`
+}
+type requestBitbucket struct {
+	EventKey   string     `json:"eventKey"`
+	Repository repository `json:"repository"`
+	Changes    []struct {
+		Type string `json:"type"`
+		Ref  struct {
+			ID        string `json:"id"`
+			DisplayID string `json:"displayId"`
+			Type      string `json:"type"`
+		} `json:"ref"`
+		FromHash string `json:"fromHash"`
+		ToHash   string `json:"toHash"`
+	} `json:"changes"`
+	PullRequest *struct {
+		FromRef struct {
+			Repository   repository `json:"repository"`
+			ID           string     `json:"id"`
+			DisplayID    string     `json:"displayId"`
+			LatestCommit string     `json:"latestCommit"`
+		} `json:"fromRef"`
+	} `json:"pullRequest"`
+	Comment *struct {
+		Text string `json:"text"`
+	} `json:"comment"`
+}
+
+func getCommitSHA(bitbucketClient bitbucket.CommitClientInterface, project, repository, gitFullRef string) (string, error) {
+	commitList, err := bitbucketClient.CommitList(project, repository, bitbucket.CommitListParams{
+		Until: gitFullRef,
+	})
+	if err != nil {
+		return "", fmt.Errorf("could not get commit list: %w", err)
+	}
+	return commitList.Values[0].ID, nil
+}
+
+type prInfo struct {
+	ID   int
+	Base string
+}
+
+func extractPullRequestInfo(bitbucketClient bitbucket.CommitClientInterface, projectKey, repositorySlug, gitCommit string) (prInfo, error) {
+	var i prInfo
+
+	prPage, err := bitbucketClient.CommitPullRequestList(projectKey, repositorySlug, gitCommit)
+	if err != nil {
+		return i, err
+	}
+
+	for _, v := range prPage.Values {
+		if !v.Open {
+			continue
+		}
+		i.ID = v.ID
+		i.Base = v.ToRef.ID
+		break
+	}
+
+	return i, nil
+}
+
+func shouldSkip(bitbucketClient bitbucket.CommitClientInterface, projectKey, repositorySlug, gitCommit string) bool {
+	c, err := bitbucketClient.CommitGet(projectKey, repositorySlug, gitCommit)
+	if err != nil {
+		return false
+	}
+	return isCiSkipInCommitMessage(c.Message)
+}
+
+// getRepoNames retrieves the name of all repositories within the project
+// identified by projectKey.
+func getRepoNames(bitbucketClient bitbucket.RepoClientInterface, projectKey string) ([]string, error) {
+	repos := []string{}
+	rl, err := bitbucketClient.RepoList(projectKey)
+	if err != nil {
+		return repos, err
+	}
+	for _, n := range rl.Values {
+		repos = append(repos, n.Name)
+	}
+	return repos, nil
+}