func()

in internal/elasticsearch/client.go [226:299]

• 65 lines of code
• 16 McCabe index (conditional complexity)

func (client *Client) redHealthCause(ctx context.Context) (string, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "/_internal/_health", nil)
	if err != nil {
		return "", fmt.Errorf("error creating internal health request: %w", err)
	}
	resp, err := client.Transport.Perform(req)
	if err != nil {
		return "", fmt.Errorf("error performing internal health request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("error reading internal health response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("failed to get cause of red health; API status code = %d; response body = %s", resp.StatusCode, string(body))
	}

	var internalHealth struct {
		Status     string `json:"status"`
		Indicators map[string]struct {
			Status  string `json:"status"`
			Impacts []struct {
				Severity int `json:"severity"`
			} `json:"impacts"`
			Diagnosis []struct {
				Cause string `json:"cause"`
			} `json:"diagnosis"`
		} `json:"indicators"`
	}
	err = json.Unmarshal(body, &internalHealth)
	if err != nil {
		return "", fmt.Errorf("error decoding internal health response: %w", err)
	}
	if internalHealth.Status != "red" {
		return "", errors.New("cluster state is not red?")
	}

	// Only diagnostics with the highest severity impacts are returned.
	var highestSeverity int
	var causes []string
	for _, indicator := range internalHealth.Indicators {
		if indicator.Status != "red" {
			continue
		}

		var severity int
		for _, impact := range indicator.Impacts {
			if impact.Severity > severity {
				severity = impact.Severity
			}
		}

		switch {
		case severity < highestSeverity:
			continue
		case severity > highestSeverity:
			highestSeverity = severity
			causes = nil
		case severity == highestSeverity:
			// Continue appending for current severity.
		}

		for _, diagnosis := range indicator.Diagnosis {
			causes = append(causes, diagnosis.Cause)
		}
	}
	if len(causes) == 0 {
		return "", errors.New("no causes found")
	}
	return strings.Join(causes, ", "), nil
}