op-conductor: add JSON-based rollup-boost healthcheck with -next suffix

op-conductor/client/rollup_boost.go → op-conductor/client/rollupboost.go

@@ -12,6 +12,7 @@ const (
 	HealthzEndpoint = "/healthz"
 )
 
+// HealthStatus represents the health state of rollup-boost.
 type HealthStatus string
 
 const (
@@ -20,26 +21,32 @@ const (
 	HealthStatusUnhealthy HealthStatus = "unhealthy"
 )
 
-type RollupBoostClient interface {
+// RollupBoostHealthChecker is the common interface for rollup-boost health checking.
+// Both RollupBoostClient and RollupBoostNextClient implement this interface.
+type RollupBoostHealthChecker interface {
 	Healthcheck(ctx context.Context) (HealthStatus, error)
 }
 
-type rollupBoostClient struct {
+// RollupBoostClient uses HTTP status codes to determine rollup-boost health.
+type RollupBoostClient struct {
 	baseURL    string
 	httpClient *http.Client
 }
 
-func NewRollupBoostClient(baseURL string, httpClient *http.Client) RollupBoostClient {
+// NewRollupBoostClient creates a client that interprets HTTP status codes for health.
+func NewRollupBoostClient(baseURL string, httpClient *http.Client) *RollupBoostClient {
 	if httpClient == nil {
 		httpClient = http.DefaultClient
 	}
-	return &rollupBoostClient{
+	return &RollupBoostClient{
 		baseURL:    baseURL,
 		httpClient: httpClient,
 	}
 }
 
-func (c *rollupBoostClient) Healthcheck(ctx context.Context) (HealthStatus, error) {
+// Healthcheck returns health status based on HTTP status codes:
+// 200 OK = Healthy, 206 Partial Content = Partial, 503 Service Unavailable = Unhealthy
+func (c *RollupBoostClient) Healthcheck(ctx context.Context) (HealthStatus, error) {
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.baseURL+HealthzEndpoint, nil)
 	if err != nil {
 		return "", fmt.Errorf("failed to create request: %w", err)
@@ -65,3 +72,6 @@ func (c *rollupBoostClient) Healthcheck(ctx context.Context) (HealthStatus, erro
 		return "", fmt.Errorf("unexpected status code: %d", resp.StatusCode)
 	}
 }
+
+// Ensure RollupBoostClient implements RollupBoostHealthChecker
+var _ RollupBoostHealthChecker = (*RollupBoostClient)(nil)

op-conductor/client/rollupboost_next.go

@@ -0,0 +1,79 @@
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+// JSON API health status values returned by rollup-boost
+const (
+	jsonHealthStatusHealthy   = "Healthy"
+	jsonHealthStatusPartial   = "PartialContent"
+	jsonHealthStatusUnhealthy = "ServiceUnavailable"
+)
+
+// RollupBoostNextClient retrieves rollup-boost health using the JSON-based healthcheck endpoint.
+type RollupBoostNextClient struct {
+	url        string
+	httpClient *http.Client
+}
+
+// RollupBoostNextHealthResponse captures the JSON payload returned by the rollup-boost health endpoint.
+type RollupBoostNextHealthResponse struct {
+	Version           string `json:"version"`
+	RollupBoostHealth string `json:"rollup_boost_health"`
+}
+
+// NewRollupBoostNextClient constructs a client for querying the rollup-boost health endpoint.
+// The url parameter should be the full URL including path (e.g., "http://localhost:8080/healthz").
+func NewRollupBoostNextClient(url string, httpClient *http.Client) *RollupBoostNextClient {
+	if httpClient == nil {
+		httpClient = http.DefaultClient
+	}
+	return &RollupBoostNextClient{
+		url:        url,
+		httpClient: httpClient,
+	}
+}
+
+// Healthcheck fetches the rollup-boost health endpoint and interprets the JSON payload.
+func (c *RollupBoostNextClient) Healthcheck(ctx context.Context) (HealthStatus, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.url, nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to create request: %w", err)
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed to make request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+	}
+
+	var payload RollupBoostNextHealthResponse
+	// Limit response size to 1 MiB to prevent memory exhaustion from malicious servers
+	if err := json.NewDecoder(io.LimitReader(resp.Body, 1<<20)).Decode(&payload); err != nil {
+		return "", fmt.Errorf("failed to decode response: %w", err)
+	}
+
+	// Map JSON API values to internal constants
+	switch payload.RollupBoostHealth {
+	case jsonHealthStatusHealthy:
+		return HealthStatusHealthy, nil
+	case jsonHealthStatusPartial:
+		return HealthStatusPartial, nil
+	case jsonHealthStatusUnhealthy:
+		return HealthStatusUnhealthy, nil
+	default:
+		return "", fmt.Errorf("unexpected rollup_boost_health: %q", payload.RollupBoostHealth)
+	}
+}
+
+// Ensure RollupBoostNextClient implements RollupBoostHealthChecker
+var _ RollupBoostHealthChecker = (*RollupBoostNextClient)(nil)