Gitlab runner scaler

pkg/scalers/gitlab_runner_scaler.go

@@ -0,0 +1,183 @@
+package scalers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/go-logr/logr"
+	v2 "k8s.io/api/autoscaling/v2"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+
+	"github.com/kedacore/keda/v2/pkg/scalers/scalersconfig"
+	kedautil "github.com/kedacore/keda/v2/pkg/util"
+)
+
+const (
+	// pipelineWaitingForResourceStatus is the status of the pipelines that are waiting for resources.
+	pipelineWaitingForResourceStatus = "waiting_for_resource"
+
+	// maxGitlabAPIPageCount is the maximum number of pages to query for pipelines.
+	maxGitlabAPIPageCount = 50
+	// gitlabAPIPerPage is the number of pipelines to query per page.
+	gitlabAPIPerPage = "200"
+)
+
+type gitlabRunnerScaler struct {
+	metricType v2.MetricTargetType
+	metadata   *gitlabRunnerMetadata
+	httpClient *http.Client
+	logger     logr.Logger
+}
+
+type gitlabRunnerMetadata struct {
+	GitLabAPIURL        *url.URL `keda:"name=gitlabAPIURL, order=triggerMetadata, default=https://gitlab.com, optional"`
+	PersonalAccessToken string   `keda:"name=personalAccessToken, order=authParams"`
+	ProjectID           string   `keda:"name=projectID, order=triggerMetadata"`
+
+	TargetPipelineQueueLength int64 `keda:"name=targetPipelineQueueLength, order=triggerMetadata, default=1, optional"`
+	TriggerIndex              int
+}
+
+// NewGitLabRunnerScaler creates a new GitLab Runner Scaler
+func NewGitLabRunnerScaler(config *scalersconfig.ScalerConfig) (Scaler, error) {
+	httpClient := kedautil.CreateHTTPClient(config.GlobalHTTPTimeout, false)
+
+	metricType, err := GetMetricTargetType(config)
+	if err != nil {
+		return nil, fmt.Errorf("error getting scaler metric type: %w", err)
+	}
+
+	meta, err := parseGitLabRunnerMetadata(config)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing GitLab Runner metadata: %w", err)
+	}
+
+	return &gitlabRunnerScaler{
+		metricType: metricType,
+		metadata:   meta,
+		httpClient: httpClient,
+		logger:     InitializeLogger(config, "gitlab_runner_scaler"),
+	}, nil
+}
+
+func parseGitLabRunnerMetadata(config *scalersconfig.ScalerConfig) (*gitlabRunnerMetadata, error) {
+	meta := gitlabRunnerMetadata{}
+
+	meta.TriggerIndex = config.TriggerIndex
+	if err := config.TypedConfig(&meta); err != nil {
+		return nil, fmt.Errorf("error parsing gitlabRunner metadata: %w", err)
+	}
+
+	uri := constructGitlabAPIPipelinesURL(*meta.GitLabAPIURL, meta.ProjectID, pipelineWaitingForResourceStatus)
+
+	meta.GitLabAPIURL = &uri
+
+	return &meta, nil
+}
+
+func (s *gitlabRunnerScaler) GetMetricsAndActivity(ctx context.Context, metricName string) ([]external_metrics.ExternalMetricValue, bool, error) {
+	queueLen, err := s.getPipelineQueueLength(ctx)
+
+	if err != nil {
+		s.logger.Error(err, "error getting workflow queue length")
+		return []external_metrics.ExternalMetricValue{}, false, err
+	}
+
+	metric := GenerateMetricInMili(metricName, float64(queueLen))
+
+	return []external_metrics.ExternalMetricValue{metric}, queueLen >= s.metadata.TargetPipelineQueueLength, nil
+}
+
+func (s *gitlabRunnerScaler) GetMetricSpecForScaling(_ context.Context) []v2.MetricSpec {
+	externalMetric := &v2.ExternalMetricSource{
+		Metric: v2.MetricIdentifier{
+			Name: GenerateMetricNameWithIndex(s.metadata.TriggerIndex, kedautil.NormalizeString(fmt.Sprintf("gitlab-runner-%s", s.metadata.ProjectID))),
+		},
+		Target: GetMetricTarget(s.metricType, s.metadata.TargetPipelineQueueLength),
+	}
+	metricSpec := v2.MetricSpec{External: externalMetric, Type: externalMetricType}
+	return []v2.MetricSpec{metricSpec}
+}
+
+func (s *gitlabRunnerScaler) Close(_ context.Context) error {
+	if s.httpClient != nil {
+		s.httpClient.CloseIdleConnections()
+	}
+	return nil
+}
+func constructGitlabAPIPipelinesURL(baseURL url.URL, projectID string, status string) url.URL {
+	baseURL.Path = "/api/v4/projects/" + projectID + "/pipelines"
+
+	qParams := baseURL.Query()
+	qParams.Set("status", status)
+	qParams.Set("per_page", gitlabAPIPerPage)
+
+	baseURL.RawQuery = qParams.Encode()
+
+	return baseURL
+}
+
+// getPipelineCount returns the number of pipelines in the GitLab project (per the page set in url)
+func (s *gitlabRunnerScaler) getPipelineCount(ctx context.Context, uri string) (int64, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, uri, nil)
+	if err != nil {
+		return 0, fmt.Errorf("creating request: %w", err)
+	}
+
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("PRIVATE-TOKEN", s.metadata.PersonalAccessToken)
+
+	res, err := s.httpClient.Do(req)
+	if err != nil {
+		return 0, fmt.Errorf("doing request: %w", err)
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode != http.StatusOK {
+		return 0, fmt.Errorf("unexpected status code: %d", res.StatusCode)
+	}
+
+	gitlabPipelines := make([]struct{}, 0)
+	if err := json.NewDecoder(res.Body).Decode(&gitlabPipelines); err != nil {
+		return 0, fmt.Errorf("decoding response: %w", err)
+	}
+
+	return int64(len(gitlabPipelines)), nil
+}
+
+// getPipelineQueueLength returns the number of pipelines in the
+// GitLab project that are waiting for resources.
+func (s *gitlabRunnerScaler) getPipelineQueueLength(ctx context.Context) (int64, error) {
+	var count int64
+
+	page := 1
+	for ; page < maxGitlabAPIPageCount; page++ {
+		pagedURL := pagedURL(*s.metadata.GitLabAPIURL, fmt.Sprint(page))
+
+		gitlabPipelinesLen, err := s.getPipelineCount(ctx, pagedURL.String())
+		if err != nil {
+			return 0, err
+		}
+
+		if gitlabPipelinesLen == 0 {
+			break
+		}
+
+		count += gitlabPipelinesLen
+	}
+
+	return count, nil
+}
+
+func pagedURL(uri url.URL, page string) url.URL {
+	qParams := uri.Query()
+	qParams.Set("page", fmt.Sprint(page))
+
+	uri.RawQuery = qParams.Encode()
+
+	return uri
+}