at-container-registry/pkg/appview/holdclient/config.go

package holdclient

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"

	"atcr.io/pkg/atproto"
)

// OCIHistoryEntry represents a single entry in the OCI config history.
type OCIHistoryEntry struct {
	Created    string `json:"created"`
	CreatedBy  string `json:"created_by"`
	EmptyLayer bool   `json:"empty_layer"`
	Comment    string `json:"comment"`
}

// OCIConfig represents the parsed OCI image config with fields useful for display.
type OCIConfig struct {
	History []OCIHistoryEntry `json:"history"`
}

// FetchImageConfig fetches the OCI image config record from the hold's
// getImageConfig XRPC endpoint. holdURL should be a resolved HTTP(S) URL.
// Returns the parsed OCI config with history entries.
func FetchImageConfig(ctx context.Context, holdURL, manifestDigest string) (*OCIConfig, error) {
	reqURL := fmt.Sprintf("%s%s?digest=%s",
		strings.TrimSuffix(holdURL, "/"),
		atproto.HoldGetImageConfig,
		url.QueryEscape(manifestDigest),
	)

	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, "GET", reqURL, nil)
	if err != nil {
		return nil, fmt.Errorf("build request: %w", err)
	}

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("fetch image config: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("hold returned status %d for %s", resp.StatusCode, reqURL)
	}

	var record struct {
		ConfigJSON string `json:"configJson"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&record); err != nil {
		return nil, fmt.Errorf("parse image config response: %w", err)
	}

	var config OCIConfig
	if err := json.Unmarshal([]byte(record.ConfigJSON), &config); err != nil {
		return nil, fmt.Errorf("parse OCI config JSON: %w", err)
	}

	return &config, nil
}