feat(deploy): tail build logs from CloudWatch while waiting

[mashiike]

Summary

• Add a --build-logs/--no-build-logs flag (default true) to deploy and wait that tails the MicroVM image build's CloudWatch Logs stream while polling for version readiness, shelling out to aws logs tail --follow scoped to the build's log stream prefix (<version>/)
• If the aws CLI is missing or fails to start, it logs a warning and continues without it — build log visibility is best-effort and never fails the wait itself

Test plan

• go build ./..., go vet ./..., golangci-lint run all clean
• go test ./... -race passes, including new unit tests for startBuildLogTail (aws CLI missing → no-op, command construction via fake aws binary, stop() does not hang) and an integration test asserting Deploy succeeds end-to-end when the aws CLI is absent
• Unverified — needs a real deploy: the build log stream name is assumed to be <imageVersion>/<uuid> (confirmed only for runtime logs, which use a different <date>[<version>]microvm-<uuid> format). Please run lamvms deploy once for a brand-new image (create) and once for an existing one (update) and confirm (a) build logs actually appear on update, and (b) no ResourceNotFoundException noise on stderr for a first-time create (the log group may not exist yet when the tail starts)

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概要

• deploy と wait に --build-logs/--no-build-logs フラグ（デフォルト true）を追加し、バージョンの準備完了をポーリングする間、MicroVM イメージビルドの CloudWatch Logs ストリームを aws logs tail --follow（ログストリーム prefix <version>/）に委譲して tail する
• aws CLI が見つからない、または起動に失敗した場合は警告ログを出して継続する（ビルドログ表示はベストエフォートであり、wait 自体を失敗させない）

テスト計画

• go build ./... / go vet ./... / golangci-lint run は全てクリーン
• go test ./... -race は全パス。startBuildLogTail の新規ユニットテスト（aws CLI 不在時の no-op、fake aws バイナリでのコマンド構築検証、stop() がハングしないこと）と、aws CLI 不在でも Deploy が最後まで成功する統合テストを追加
• 未検証・実機確認が必要: ビルドログのストリーム名が <imageVersion>/<uuid> 形式であるという前提は仮説です（確認済みなのはランタイムログの <date>[<version>]microvm-<uuid> 形式のみ）。新規イメージ（create）と既存イメージ更新（update）でそれぞれ1回 lamvms deploy を実行し、(a) update でビルドログが実際に流れるか、(b) create でロググループ未作成による ResourceNotFoundException 等が stderr に出ないかを確認してください

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds best-effort tailing of MicroVM image build logs from CloudWatch while deploy --wait / wait polls for version readiness, by shelling out to aws logs tail --follow scoped to the version’s log-stream prefix.

Changes:

• Add --build-logs/--no-build-logs (default true) to deploy and wait, and pass the setting down to waitForVersion.
• Start/stop an aws logs tail --follow --log-stream-name-prefix <version>/ subprocess while waiting for the image version to become ready.
• Add tests covering startBuildLogTail behavior and an integration-style test ensuring deploy succeeds when aws CLI is missing.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
wait.go	Passes BuildLogs through to the version-wait loop.
deploy.go	Implements build-log tailing during version wait; improves failure hint to include the computed log group name.
logs.go	Deduplicates log-group name formatting via microvmLogGroupName.
cli.go	Adds --build-logs/--no-build-logs flags to deploy and wait.
deploy_test.go	Adds tests for best-effort behavior and tail process lifecycle/command construction.
README.md	Documents the new --build-logs/--no-build-logs flags.
README.ja.md	Japanese documentation update for the new flags.