From 164a9d0a3e3ede4b0b262f055f99e5e30bc16fbb Mon Sep 17 00:00:00 2001 From: Michael Darakananda Date: Thu, 22 Sep 2016 16:58:16 +1000 Subject: [PATCH 1/2] metadata.NewContext merges old metadata Previously metadata.NewContext(ctx, md) replaces whatever metadata in ctx with md. This patch merges the old metadata with md before returning the new context. Fixes #902. --- metadata/metadata.go | 13 ++++++++++--- metadata/metadata_test.go | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+), 3 deletions(-) diff --git a/metadata/metadata.go b/metadata/metadata.go index 954c0f77..c8bb1020 100644 --- a/metadata/metadata.go +++ b/metadata/metadata.go @@ -117,10 +117,14 @@ func (md MD) Len() int { // Copy returns a copy of md. func (md MD) Copy() MD { + return join(md) +} + +func join(mds ...MD) MD { out := MD{} - for k, v := range md { - for _, i := range v { - out[k] = append(out[k], i) + for _, md := range mds { + for k, v := range md { + out[k] = append(out[k], v...) } } return out @@ -130,6 +134,9 @@ type mdKey struct{} // NewContext creates a new context with md attached. func NewContext(ctx context.Context, md MD) context.Context { + if old, ok := FromContext(ctx); ok { + return context.WithValue(ctx, mdKey{}, join(old, md)) + } return context.WithValue(ctx, mdKey{}, md) } diff --git a/metadata/metadata_test.go b/metadata/metadata_test.go index 99e86820..b4871fac 100644 --- a/metadata/metadata_test.go +++ b/metadata/metadata_test.go @@ -36,6 +36,8 @@ package metadata import ( "reflect" "testing" + + "golang.org/x/net/context" ) const binaryValue = string(128) @@ -107,3 +109,39 @@ func TestPairsMD(t *testing.T) { } } } + +func TestCopy(t *testing.T) { + const key, val = "key", "val" + orig := Pairs(key, val) + copy := orig.Copy() + if !reflect.DeepEqual(orig, copy) { + t.Errorf("copied value not equal to the original, got %v, want %v", copy, orig) + } + orig[key][0] = "foo" + if v := copy[key][0]; v != val { + t.Errorf("change in original should not affect copy, got %q, want %q", v, val) + } +} + +func TestContext(t *testing.T) { + ctx := context.Background() + if md, ok := FromContext(ctx); len(md) != 0 || ok { + t.Errorf("found (%v, %t), want (%v, %t)", md, ok, nil, false) + } + + for _, test := range []struct { + add, want MD + }{ + {Pairs("foo", "bar"), Pairs("foo", "bar")}, + {Pairs("foo", "baz"), Pairs("foo", "bar", "foo", "baz")}, + {Pairs("zip", "zap"), Pairs("foo", "bar", "foo", "baz", "zip", "zap")}, + } { + ctx = NewContext(ctx, test.add) + md, ok := FromContext(ctx) + if !ok { + t.Errorf("context missing metadata after adding %v", test.add) + } else if !reflect.DeepEqual(md, test.want) { + t.Errorf("context's metadata is %v, want %v", md, test.want) + } + } +} From b32ff193313ca79055cc7fd8bbc5a24b7eef294f Mon Sep 17 00:00:00 2001 From: Michael Darakananda Date: Fri, 23 Sep 2016 11:12:52 +1000 Subject: [PATCH 2/2] Add context.Join instead --- metadata/metadata.go | 10 +++++----- metadata/metadata_test.go | 26 +++++++++----------------- 2 files changed, 14 insertions(+), 22 deletions(-) diff --git a/metadata/metadata.go b/metadata/metadata.go index c8bb1020..3c0ca7a3 100644 --- a/metadata/metadata.go +++ b/metadata/metadata.go @@ -117,10 +117,13 @@ func (md MD) Len() int { // Copy returns a copy of md. func (md MD) Copy() MD { - return join(md) + return Join(md) } -func join(mds ...MD) MD { +// Join joins any number of MDs into a single MD. +// The order of values for each key is determined by the order in which +// the MDs containing those values are presented to Join. +func Join(mds ...MD) MD { out := MD{} for _, md := range mds { for k, v := range md { @@ -134,9 +137,6 @@ type mdKey struct{} // NewContext creates a new context with md attached. func NewContext(ctx context.Context, md MD) context.Context { - if old, ok := FromContext(ctx); ok { - return context.WithValue(ctx, mdKey{}, join(old, md)) - } return context.WithValue(ctx, mdKey{}, md) } diff --git a/metadata/metadata_test.go b/metadata/metadata_test.go index b4871fac..fef0a0f8 100644 --- a/metadata/metadata_test.go +++ b/metadata/metadata_test.go @@ -36,8 +36,6 @@ package metadata import ( "reflect" "testing" - - "golang.org/x/net/context" ) const binaryValue = string(128) @@ -123,24 +121,18 @@ func TestCopy(t *testing.T) { } } -func TestContext(t *testing.T) { - ctx := context.Background() - if md, ok := FromContext(ctx); len(md) != 0 || ok { - t.Errorf("found (%v, %t), want (%v, %t)", md, ok, nil, false) - } - +func TestJoin(t *testing.T) { for _, test := range []struct { - add, want MD + mds []MD + want MD }{ - {Pairs("foo", "bar"), Pairs("foo", "bar")}, - {Pairs("foo", "baz"), Pairs("foo", "bar", "foo", "baz")}, - {Pairs("zip", "zap"), Pairs("foo", "bar", "foo", "baz", "zip", "zap")}, + {[]MD{}, MD{}}, + {[]MD{Pairs("foo", "bar")}, Pairs("foo", "bar")}, + {[]MD{Pairs("foo", "bar"), Pairs("foo", "baz")}, Pairs("foo", "bar", "foo", "baz")}, + {[]MD{Pairs("foo", "bar"), Pairs("foo", "baz"), Pairs("zip", "zap")}, Pairs("foo", "bar", "foo", "baz", "zip", "zap")}, } { - ctx = NewContext(ctx, test.add) - md, ok := FromContext(ctx) - if !ok { - t.Errorf("context missing metadata after adding %v", test.add) - } else if !reflect.DeepEqual(md, test.want) { + md := Join(test.mds...) + if !reflect.DeepEqual(md, test.want) { t.Errorf("context's metadata is %v, want %v", md, test.want) } }