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Switch pager to return whether the result was paginated

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Kubernetes-commit: 5dcf08c1993718e94cf6537af50e0a411dd2878c
This commit is contained in:
wojtekt
2020-01-28 09:39:27 +01:00
committed by Kubernetes Publisher
parent 5534e24283
commit 0e2dbbf70a
4 changed files with 144 additions and 52 deletions
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21
tools/pager/pager.go
View File

@@ -73,16 +73,18 @@ func New(fn ListPageFunc) *ListPager {
// List returns a single list object, but attempts to retrieve smaller chunks from the
// server to reduce the impact on the server. If the chunk attempt fails, it will load
// the full list instead. The Limit field on options, if unset, will default to the page size.
func (p *ListPager) List(ctx context.Context, options metav1.ListOptions) (runtime.Object, error) {
func (p *ListPager) List(ctx context.Context, options metav1.ListOptions) (runtime.Object, bool, error) {
if options.Limit == 0 {
options.Limit = p.PageSize
}
requestedResourceVersion := options.ResourceVersion
var list *metainternalversion.List
paginatedResult := false
for {
select {
case <-ctx.Done():
return nil, ctx.Err()
return nil, paginatedResult, ctx.Err()
default:
}
@@ -93,23 +95,24 @@ func (p *ListPager) List(ctx context.Context, options metav1.ListOptions) (runti
// failing when the resource versions is established by the first page request falls out of the compaction
// during the subsequent list requests).
if !errors.IsResourceExpired(err) || !p.FullListIfExpired || options.Continue == "" {
return nil, err
return nil, paginatedResult, err
}
// the list expired while we were processing, fall back to a full list at
// the requested ResourceVersion.
options.Limit = 0
options.Continue = ""
options.ResourceVersion = requestedResourceVersion
return p.PageFn(ctx, options)
result, err := p.PageFn(ctx, options)
return result, paginatedResult, err
}
m, err := meta.ListAccessor(obj)
if err != nil {
return nil, fmt.Errorf("returned object must be a list: %v", err)
return nil, paginatedResult, fmt.Errorf("returned object must be a list: %v", err)
}
// exit early and return the object we got if we haven't processed any pages
if len(m.GetContinue()) == 0 && list == nil {
return obj, nil
return obj, paginatedResult, nil
}
// initialize the list and fill its contents
@@ -122,12 +125,12 @@ func (p *ListPager) List(ctx context.Context, options metav1.ListOptions) (runti
list.Items = append(list.Items, obj)
return nil
}); err != nil {
return nil, err
return nil, paginatedResult, err
}
// if we have no more items, return the list
if len(m.GetContinue()) == 0 {
return list, nil
return list, paginatedResult, nil
}
// set the next loop up
@@ -136,6 +139,8 @@ func (p *ListPager) List(ctx context.Context, options metav1.ListOptions) (runti
// `specifying resource version is not allowed when using continue` error.
// See https://github.com/kubernetes/kubernetes/issues/85221#issuecomment-553748143.
options.ResourceVersion = ""
// At this point, result is already paginated.
paginatedResult = true
}
}

67
tools/pager/pager_test.go
View File

@@ -120,6 +120,7 @@ func (p *testPager) ExpiresOnSecondPageThenFullList(ctx context.Context, options
}
return p.PagedList(ctx, options)
}
func TestListPager_List(t *testing.T) {
type fields struct {
PageSize int64
@@ -135,43 +136,50 @@ func TestListPager_List(t *testing.T) {
fields fields
args args
want runtime.Object
wantPaged bool
wantErr bool
isExpired bool
}{
{
name: "empty page",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 0, rv: "rv:20"}).PagedList},
args: args{},
want: list(0, "rv:20"),
name: "empty page",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 0, rv: "rv:20"}).PagedList},
args: args{},
want: list(0, "rv:20"),
wantPaged: false,
},
{
name: "one page",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 9, rv: "rv:20"}).PagedList},
args: args{},
want: list(9, "rv:20"),
name: "one page",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 9, rv: "rv:20"}).PagedList},
args: args{},
want: list(9, "rv:20"),
wantPaged: false,
},
{
name: "one full page",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 10, rv: "rv:20"}).PagedList},
args: args{},
want: list(10, "rv:20"),
name: "one full page",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 10, rv: "rv:20"}).PagedList},
args: args{},
want: list(10, "rv:20"),
wantPaged: false,
},
{
name: "two pages",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 11, rv: "rv:20"}).PagedList},
args: args{},
want: list(11, "rv:20"),
name: "two pages",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 11, rv: "rv:20"}).PagedList},
args: args{},
want: list(11, "rv:20"),
wantPaged: true,
},
{
name: "three pages",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 21, rv: "rv:20"}).PagedList},
args: args{},
want: list(21, "rv:20"),
name: "three pages",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 21, rv: "rv:20"}).PagedList},
args: args{},
want: list(21, "rv:20"),
wantPaged: true,
},
{
name: "expires on second page",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 21, rv: "rv:20"}).ExpiresOnSecondPage},
args: args{},
wantPaged: true,
wantErr: true,
isExpired: true,
},
@@ -182,14 +190,16 @@ func TestListPager_List(t *testing.T) {
PageSize: 10,
PageFn: (&testPager{t: t, expectPage: 10, remaining: 21, rv: "rv:20"}).ExpiresOnSecondPageThenFullList,
},
args: args{},
want: list(21, "rv:20"),
args: args{},
want: list(21, "rv:20"),
wantPaged: true,
},
{
name: "two pages with resourceVersion",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 11, rv: "rv:20"}).PagedList},
args: args{options: metav1.ListOptions{ResourceVersion: "rv:10"}},
want: list(11, "rv:20"),
name: "two pages with resourceVersion",
fields: fields{PageSize: 10, PageFn: (&testPager{t: t, expectPage: 10, remaining: 11, rv: "rv:20"}).PagedList},
args: args{options: metav1.ListOptions{ResourceVersion: "rv:10"}},
want: list(11, "rv:20"),
wantPaged: true,
},
}
for _, tt := range tests {
@@ -203,7 +213,7 @@ func TestListPager_List(t *testing.T) {
if ctx == nil {
ctx = context.Background()
}
got, err := p.List(ctx, tt.args.options)
got, paginatedResult, err := p.List(ctx, tt.args.options)
if (err != nil) != tt.wantErr {
t.Errorf("ListPager.List() error = %v, wantErr %v", err, tt.wantErr)
return
@@ -212,6 +222,9 @@ func TestListPager_List(t *testing.T) {
t.Errorf("ListPager.List() error = %v, isExpired %v", err, tt.isExpired)
return
}
if tt.wantPaged != paginatedResult {
t.Errorf("paginatedResult = %t, want %t", paginatedResult, tt.wantPaged)
}
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("ListPager.List() = %v, want %v", got, tt.want)
}