Merge pull request #4 from crazy-max/buildx-version

buildx: do not set version in constructor

__tests__/buildx.test.ts

@@ -107,12 +107,12 @@ describe('printVersion', () => {
   });
 });
 
-describe('getVersion', () => {
+describe('version', () => {
   it('valid', async () => {
     const buildx = new Buildx({
       context: new Context()
     });
-    expect(semver.valid(await buildx.version)).not.toBeNull();
+    expect(semver.valid(await buildx.version)).not.toBeUndefined();
   });
 });
 

src/buildx.ts

@@ -15,13 +15,13 @@ export interface BuildxOpts {
 
 export class Buildx {
   private readonly context: Context;
+  private _version: string | undefined;
+
   public standalone: boolean;
-  public version: Promise<string>;
 
   constructor(opts: BuildxOpts) {
     this.context = opts.context;
     this.standalone = opts?.standalone ?? !Docker.isAvailable();
-    this.version = this.getVersion();
   }
 
   public getCommand(args: Array<string>) {
@@ -57,9 +57,11 @@ export class Buildx {
     });
   }
 
-  private async getVersion(): Promise<string> {
+  get version() {
+    return (async () => {
+      if (!this._version) {
         const cmd = this.getCommand(['version']);
-    return await exec
+        this._version = await exec
           .getExecOutput(cmd.command, cmd.args, {
             ignoreReturnCode: true,
             silent: true
@@ -71,6 +73,9 @@ export class Buildx {
             return Buildx.parseVersion(res.stdout.trim());
           });
       }
+      return this._version;
+    })();
+  }
 
   public async printVersion() {
     const cmd = this.getCommand(['version']);
@@ -89,6 +94,9 @@ export class Buildx {
 
   public async versionSatisfies(range: string, version?: string): Promise<boolean> {
     const ver = version ?? (await this.version);
+    if (!ver) {
+      return false;
+    }
     return semver.satisfies(ver, range) || /^[0-9a-f]{7}$/.exec(ver) !== null;
   }