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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,67 @@ | ||
| package hashring | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "sort" | ||
| "strconv" | ||
| "strings" | ||
|
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| "github.com/dgryski/go-farm" | ||
| ) | ||
|
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| // Checksum computes a checksum for an instance of a HashRing. The | ||
| // checksum can be used to compare two rings for equality. | ||
| type Checksum interface { | ||
| // Compute calculates the checksum for the hashring that is passed in. | ||
| // Compute will be called while having at least a read-lock on the hashring so | ||
| // it is safe to read from the ring, but not safe to change the ring. There | ||
| // might be multiple Checksum Computes initiated at the same time, but every | ||
| // Checksum will only be called once per hashring at once | ||
| Compute(ring *HashRing) (checksum uint32) | ||
| } | ||
|
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| // addressChecksum calculates checksums for all addresses that are added to the | ||
| // hashring. | ||
| type addressChecksum struct{} | ||
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| func (i *addressChecksum) Compute(ring *HashRing) uint32 { | ||
| addresses := ring.copyServersNoLock() | ||
| sort.Strings(addresses) | ||
| bytes := []byte(strings.Join(addresses, ";")) | ||
| return farm.Fingerprint32(bytes) | ||
| } | ||
|
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| type identityChecksum struct{} | ||
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| func (i *identityChecksum) Compute(ring *HashRing) uint32 { | ||
| identitySet := make(map[string]struct{}) | ||
| ring.tree.root.walk(func(node *redBlackNode) bool { | ||
| identitySet[node.key.(replicaPoint).identity] = struct{}{} | ||
| return true | ||
| }) | ||
|
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| identities := make([]string, 0, len(identitySet)) | ||
| for identity := range identitySet { | ||
| identities = append(identities, identity) | ||
| } | ||
|
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| sort.Strings(identities) | ||
| bytes := []byte(strings.Join(identities, ";")) | ||
| return farm.Fingerprint32(bytes) | ||
| } | ||
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| type replicaPointChecksum struct{} | ||
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| func (r *replicaPointChecksum) Compute(ring *HashRing) uint32 { | ||
| buffer := bytes.Buffer{} | ||
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| ring.tree.root.walk(func(node *redBlackNode) bool { | ||
| buffer.WriteString(strconv.Itoa(node.key.(replicaPoint).hash)) | ||
| buffer.WriteString("-") | ||
| buffer.WriteString(node.value.(string)) | ||
| buffer.WriteString(";") | ||
| return true | ||
| }) | ||
|
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| return farm.Fingerprint32(buffer.Bytes()) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,85 @@ | ||
| // Copyright (c) 2015 Uber Technologies, Inc. | ||
| // | ||
| // Permission is hereby granted, free of charge, to any person obtaining a copy | ||
| // of this software and associated documentation files (the "Software"), to deal | ||
| // in the Software without restriction, including without limitation the rights | ||
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | ||
| // copies of the Software, and to permit persons to whom the Software is | ||
| // furnished to do so, subject to the following conditions: | ||
| // | ||
| // The above copyright notice and this permission notice shall be included in | ||
| // all copies or substantial portions of the Software. | ||
| // | ||
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | ||
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | ||
| // THE SOFTWARE. | ||
|
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| package hashring | ||
|
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| import ( | ||
| "sort" | ||
| "strings" | ||
| "testing" | ||
|
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| "github.com/dgryski/go-farm" | ||
| "github.com/stretchr/testify/assert" | ||
| ) | ||
|
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| func TestAddressChecksum_Compute(t *testing.T) { | ||
| members := genMembers(1, 1, 10, false) | ||
| ring := New(farm.Fingerprint32, 1) | ||
| ring.AddMembers(members...) | ||
| checksum := &addressChecksum{} | ||
|
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| addresses := make([]string, 0, 10) | ||
| for _, members := range members { | ||
| addresses = append(addresses, members.GetAddress()) | ||
| } | ||
|
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| sort.Strings(addresses) | ||
| bytes := []byte(strings.Join(addresses, ";")) | ||
|
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| expected := farm.Fingerprint32(bytes) | ||
| actual := checksum.Compute(ring) | ||
|
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| assert.Equal(t, expected, actual) | ||
| } | ||
|
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| func TestIdentityChecksum_Compute(t *testing.T) { | ||
| identityChecksummer := &identityChecksum{} | ||
|
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| ringWithoutIdentities := New(farm.Fingerprint32, 1) | ||
| ringWithoutIdentities.AddMembers(genMembers(1, 1, 10, false)...) | ||
|
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| legacyChecksum := (&addressChecksum{}).Compute(ringWithoutIdentities) | ||
| identityChecksum := identityChecksummer.Compute(ringWithoutIdentities) | ||
|
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| assert.Equal(t, legacyChecksum, identityChecksum, "Identity checksum should be the same as legacy on ring without identities") | ||
|
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| ringWithIdentities := New(farm.Fingerprint32, 1) | ||
| ringWithIdentities.AddMembers(genMembers(1, 1, 10, true)...) | ||
|
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| identityChecksum = identityChecksummer.Compute(ringWithIdentities) | ||
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| assert.NotEqual(t, legacyChecksum, identityChecksum, "IdentityChecksummer should not match legacy checksummer on ring with identites ") | ||
| } | ||
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| func TestReplicaPointChecksum_Compute(t *testing.T) { | ||
| replicaPointChecksummer := &replicaPointChecksum{} | ||
| members := genMembers(1, 1, 10, false) | ||
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| ring1ReplicaPoint := New(farm.Fingerprint32, 1) | ||
| ring1ReplicaPoint.AddMembers(members...) | ||
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| ring2ReplicaPoints := New(farm.Fingerprint32, 2) | ||
| ring2ReplicaPoints.AddMembers(members...) | ||
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| checksum1ReplicaPoint := replicaPointChecksummer.Compute(ring1ReplicaPoint) | ||
| checksum2ReplicaPoints := replicaPointChecksummer.Compute(ring2ReplicaPoints) | ||
|
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| assert.NotEqual(t, checksum1ReplicaPoint, checksum2ReplicaPoints, "Checksum should not match with different replica point counts") | ||
| } |
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