refactor: rename updater package to update

internal/update/release.go

@@ -0,0 +1,82 @@
+package update
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"runtime"
+)
+
+const (
+	repoOwner        = "mathismqn"
+	repoName         = "godeez"
+	latestReleaseURL = "https://api.github.com/repos/" + repoOwner + "/" + repoName + "/releases/latest"
+	checksumsAsset   = "checksums.txt"
+	maxResponseSize  = 1 << 20
+)
+
+var githubAPIHeaders = map[string]string{
+	"Accept":               "application/vnd.github+json",
+	"X-GitHub-Api-Version": "2022-11-28",
+}
+
+type Release struct {
+	TagName string  `json:"tag_name"`
+	Assets  []Asset `json:"assets"`
+}
+
+type Asset struct {
+	Name string `json:"name"`
+	URL  string `json:"browser_download_url"`
+}
+
+func (u *Updater) Latest(ctx context.Context) (*Release, error) {
+	ctx, cancel := context.WithTimeout(ctx, apiTimeout)
+	defer cancel()
+
+	body, err := u.get(ctx, latestReleaseURL, githubAPIHeaders)
+	if err != nil {
+		return nil, err
+	}
+	defer body.Close()
+
+	var release Release
+	if err := json.NewDecoder(io.LimitReader(body, maxResponseSize)).Decode(&release); err != nil {
+		return nil, fmt.Errorf("failed to decode release: %w", err)
+	}
+	if release.TagName == "" {
+		return nil, fmt.Errorf("release has no tag name")
+	}
+
+	return &release, nil
+}
+
+func (r *Release) Version() string {
+	return trimV(r.TagName)
+}
+
+func (r *Release) asset(name string) (Asset, bool) {
+	for _, a := range r.Assets {
+		if a.Name == name {
+			return a, true
+		}
+	}
+
+	return Asset{}, false
+}
+
+func (r *Release) assetForRuntime() (Asset, error) {
+	name := fmt.Sprintf("%s_%s_%s_%s", repoName, r.Version(), runtime.GOOS, runtime.GOARCH)
+	if runtime.GOOS == "windows" {
+		name += ".exe"
+	}
+
+	asset, ok := r.asset(name)
+	if !ok {
+		return Asset{}, fmt.Errorf("release %s has no binary for %s/%s (expected %s)",
+			r.TagName, runtime.GOOS, runtime.GOARCH, name)
+	}
+
+	return asset, nil
+}