dashboard: implement asset storage

Asset is a file/attachment relevant for debugging a kernel crash or the
syzbot itself.

Dashboard keeps track of the uploaded assets and manages their lifetime.
Some of the assets are attached to the bug reports sent by syzkaller,
some (like html coverage report) are displayed on the web portal.

Two new API requests:
* add_build_assets -- let dashboard remember one more build-related
  asset.
* needed_assets -- query the list of assets that are still needed by the
  dashboard.

1 files changed, 49 insertions, 0 deletions

diff --git a/dashboard/dashapi/dashapi.go b/dashboard/dashapi/dashapi.go
index 028448b33..cdefb8080 100644
--- a/dashboard/dashapi/dashapi.go
+++ b/dashboard/dashapi/dashapi.go
@@ -102,6 +102,7 @@ type Build struct {
 	KernelConfig        []byte
 	Commits             []string // see BuilderPoll
 	FixCommits          []Commit
+	Assets              []NewAsset
 }
 
 type Commit struct {
@@ -396,8 +397,27 @@ type BugReport struct {
 	PatchLink      string
 	BisectCause    *BisectResult
 	BisectFix      *BisectResult
+	Assets         []Asset
 }
 
+type Asset struct {
+	Title       string
+	DownloadURL string
+	Type        AssetType
+}
+
+type AssetType string
+
+// Asset types used throughout the system.
+// DO NOT change them, this will break compatibility with DB content.
+const (
+	BootableDisk       AssetType = "bootable_disk"
+	NonBootableDisk    AssetType = "non_bootable_disk"
+	KernelObject       AssetType = "kernel_object"
+	KernelImage        AssetType = "kernel_image"
+	HTMLCoverageReport AssetType = "html_coverage_report"
+)
+
 type BisectResult struct {
 	Commit          *Commit   // for conclusive bisection
 	Commits         []*Commit // for inconclusive bisection
@@ -537,6 +557,35 @@ func (dash *Dashboard) UploadManagerStats(req *ManagerStatsReq) error {
 	return dash.Query("manager_stats", req, nil)
 }
 
+// Asset lifetime:
+// 1. syz-ci uploads it to GCS and reports to the dashboard via add_build_asset.
+// 2. dashboard periodically checks if the asset is still needed.
+// 3. syz-ci queries needed_assets to figure out which assets are still needed.
+// 4. Once an asset is not needed, syz-ci removes the corresponding file.
+type NewAsset struct {
+	DownloadURL string
+	Type        AssetType
+}
+
+type AddBuildAssetsReq struct {
+	BuildID string
+	Assets  []NewAsset
+}
+
+func (dash *Dashboard) AddBuildAssets(req *AddBuildAssetsReq) error {
+	return dash.Query("add_build_assets", req, nil)
+}
+
+type NeededAssetsResp struct {
+	DownloadURLs []string
+}
+
+func (dash *Dashboard) NeededAssetsList() (*NeededAssetsResp, error) {
+	resp := new(NeededAssetsResp)
+	err := dash.Query("needed_assets", nil, resp)
+	return resp, err
+}
+
 type BugListResp struct {
 	List []string
 }