feat(platform): report capacity check health

vehicle-data-platform/apps/api/internal/platform/capacity_check.go

@@ -0,0 +1,53 @@
+package platform
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"os/exec"
+	"strings"
+)
+
+type CapacityCheckResult struct {
+	Status            string   `json:"status"`
+	ActiveConnections int64    `json:"active_connections"`
+	KafkaLag          float64  `json:"kafka_lag"`
+	Findings          []string `json:"findings"`
+}
+
+type capacityCheckReport struct {
+	Status string `json:"status"`
+	Totals struct {
+		ActiveConnections int64   `json:"active_connections"`
+		KafkaLag          float64 `json:"kafka_lag"`
+	} `json:"totals"`
+	Findings []string `json:"findings"`
+}
+
+type CapacityCheckCommand struct {
+	bin string
+}
+
+func NewCapacityCheckCommand(bin string) *CapacityCheckCommand {
+	return &CapacityCheckCommand{bin: strings.TrimSpace(bin)}
+}
+
+func (c *CapacityCheckCommand) CheckCapacity(ctx context.Context) (CapacityCheckResult, error) {
+	if c.bin == "" {
+		return CapacityCheckResult{}, errors.New("capacity-check bin is empty")
+	}
+	output, err := exec.CommandContext(ctx, c.bin).CombinedOutput()
+	var report capacityCheckReport
+	if jsonErr := json.Unmarshal(output, &report); jsonErr != nil {
+		if err != nil {
+			return CapacityCheckResult{}, errors.New(err.Error() + ": " + strings.TrimSpace(string(output)))
+		}
+		return CapacityCheckResult{}, jsonErr
+	}
+	return CapacityCheckResult{
+		Status:            report.Status,
+		ActiveConnections: report.Totals.ActiveConnections,
+		KafkaLag:          report.Totals.KafkaLag,
+		Findings:          report.Findings,
+	}, nil
+}