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Merged
yurishkuro merged 7 commits into from
Jul 10, 2018
Merged

Do not exceed ES _id length limit #905

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6f43001
leave document _id generation to Eleasticsearch
tmszdmsk Jul 2, 2018
3489723
Calculate sha256 checksum for document _id for Elasticsearch.
harnash Jul 4, 2018
10fcf67
Using Hashable interface to calculate Elasticsearch ids
harnash Jul 5, 2018
762c739
Introduce Service::hashCode() to calculate Elasticsearch _id
harnash Jul 9, 2018
658cec6
Merge branch 'master' into 779-ES-autogenerate-id
harnash Jul 9, 2018
3d46c8a
Do not calculate Service hash in tests
harnash Jul 10, 2018
8e909f5
Merge branch 'master' into 779-ES-autogenerate-id
harnash Jul 10, 2018
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7 changes: 3 additions & 4 deletions plugin/storage/es/spanstore/service_operation.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,6 @@ package spanstore

import (
"context"
"fmt"
"time"

"github.com/pkg/errors"
Expand Down Expand Up @@ -74,10 +73,10 @@ func (s *ServiceOperationStorage) Write(indexName string, jsonSpan *jModel.Span)
ServiceName: jsonSpan.Process.ServiceName,
OperationName: jsonSpan.OperationName,
}
serviceID := fmt.Sprintf("%s|%s", service.ServiceName, service.OperationName)
cacheKey := fmt.Sprintf("%s:%s", indexName, serviceID)

cacheKey := service.hashCode()
if !keyInCache(cacheKey, s.serviceCache) {
s.client.Index().Index(indexName).Type(serviceType).Id(serviceID).BodyJson(service).Add()
s.client.Index().Index(indexName).Type(serviceType).Id(cacheKey).BodyJson(service).Add()
writeCache(cacheKey, s.serviceCache)
}
}
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8 changes: 6 additions & 2 deletions plugin/storage/es/spanstore/service_operation_test.go
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Expand Up @@ -31,9 +31,11 @@ func TestWriteService(t *testing.T) {
indexService := &mocks.IndexService{}

indexName := "jaeger-1995-04-21"
serviceHash := "de3b5a8f1a79989d"

indexService.On("Index", stringMatcher(indexName)).Return(indexService)
indexService.On("Type", stringMatcher(serviceType)).Return(indexService)
indexService.On("Id", stringMatcher("service|operation")).Return(indexService)
indexService.On("Id", stringMatcher(serviceHash)).Return(indexService)
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@black-adder black-adder Jul 9, 2018

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I'm not a big fan of using the same hash function here to test that the service was hashed, I'd prefer if you generated this hash once and compare against the actual hash string.

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@harnash harnash Jul 10, 2018

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I've removed calls to hashCode() and put static hash in those tests.

indexService.On("BodyJson", mock.AnythingOfType("spanstore.Service")).Return(indexService)
indexService.On("Add")

Expand Down Expand Up @@ -64,9 +66,11 @@ func TestWriteServiceError(t *testing.T) {
indexService := &mocks.IndexService{}

indexName := "jaeger-1995-04-21"
serviceHash := "de3b5a8f1a79989d"

indexService.On("Index", stringMatcher(indexName)).Return(indexService)
indexService.On("Type", stringMatcher(serviceType)).Return(indexService)
indexService.On("Id", stringMatcher("service|operation")).Return(indexService)
indexService.On("Id", stringMatcher(serviceHash)).Return(indexService)
indexService.On("BodyJson", mock.AnythingOfType("spanstore.Service")).Return(indexService)
indexService.On("Add")

Expand Down
9 changes: 9 additions & 0 deletions plugin/storage/es/spanstore/writer.go
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Expand Up @@ -16,6 +16,8 @@ package spanstore

import (
"context"
"fmt"
"hash/fnv"
"strconv"
"strings"
"time"
Expand Down Expand Up @@ -73,6 +75,13 @@ type Span struct {
StartTimeMillis uint64 `json:"startTimeMillis"`
}

func (s Service) hashCode() string {
h := fnv.New64a()
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@black-adder black-adder Jul 9, 2018

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can this be cached?

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@harnash harnash Jul 10, 2018

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@black-adder It could be but it will introduce issue with concurrency. Every simultaneous call to this function would potentially cause race condition and would render unpredictable hash results. I would need to introduce some kind of semaphore and mark this part as critical section. Do you think it is worth?

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@black-adder black-adder Jul 10, 2018

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unpredictable hash results -> shouldn't this always produce the same hash results for the same key even if run concurrently? I actually dont know the inner workings of the implementation so maybe completely wrong, we can skip for now but can you add a TODO to investigate in the future (unless you already know that there will be race conditions).

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@harnash harnash Jul 12, 2018

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@black-adder so my reasoning is like this.

  1. You store cached hasher object somewhere (most likely in the writer.go) and use it whenever someone calls hashCode()
  2. First process (1) calls hashCode(), fetches (creates if not cached) hasher object
  3. (1) Pushes data: OperationName and ServiceName to the hasher
  4. Second process (2) calls hashCode() which fetches the same (cached) hasher object
  5. (2) pushes its OperationName and ServiceName to the same hasher
  6. (1) calculates checksum by calling Sum64() on the same hasher (which now holds data from two possibly different instances of Service)
  7. (2) does the calculations too and gets the same (wrong) hash as (1)

I did actually run into this issue while fixing the tests :-)

Even if I introduce hash.Reset() just after Sum64() or before data is pushed it the hasher I still have no guarantees that other process is not doing some operation on the cached object. Putting Write semaphore would probably do the trick but I think it is a bit overkill in this case.

I hope this helps.

h.Write([]byte(s.ServiceName))
h.Write([]byte(s.OperationName))
return fmt.Sprintf("%x", h.Sum64())
}

// NewSpanWriter creates a new SpanWriter for use
func NewSpanWriter(
client es.Client,
Expand Down
3 changes: 2 additions & 1 deletion plugin/storage/es/spanstore/writer_test.go
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Expand Up @@ -134,6 +134,7 @@ func TestSpanWriter_WriteSpan(t *testing.T) {

spanIndexName := "jaeger-span-1995-04-21"
serviceIndexName := "jaeger-service-1995-04-21"
serviceHash := "de3b5a8f1a79989d"

serviceExistsService := &mocks.IndicesExistsService{}
spanExistsService := &mocks.IndicesExistsService{}
Expand All @@ -159,7 +160,7 @@ func TestSpanWriter_WriteSpan(t *testing.T) {
indexService.On("Type", stringMatcher(serviceType)).Return(indexServicePut)
indexService.On("Type", stringMatcher(spanType)).Return(indexSpanPut)

indexServicePut.On("Id", stringMatcher("service|operation")).Return(indexServicePut)
indexServicePut.On("Id", stringMatcher(serviceHash)).Return(indexServicePut)
indexServicePut.On("BodyJson", mock.AnythingOfType("spanstore.Service")).Return(indexServicePut)
indexServicePut.On("Add")

Expand Down