Develop Reference

Is there any way to guarantee that an ElasticSearch index has been deleted

In some automated tests, I am trying to delete and immediately recreate an index at the start of every test, using ElasticSearch's high-level rest client (version 6.4), as follows:
DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest(indexName);
deleteIndexRequest.indicesOptions(IndicesOptions.lenientExpandOpen());
client.indices().delete(deleteIndexRequest, RequestOptions.DEFAULT);
CreateIndexRequest createIndexRequest = new CreateIndexRequest(indexName);
request.mapping("_doc", "{...}", XContentType.JSON);
client.indices().create(request, RequestOptions.DEFAULT);
The problem I have is that, intermittently, my tests fail at the point of creating the index, with an error:
{"error": {"root_cause":[{"type":"resource_already_exists_exception","reason":"index [(index-name)/(UUID)] already exists, ...,}] "status":400}
The more tests I run, the more likely I am to see the error, which seems to be a strong indicator that it's a race condition - presumably when I try to recreate the index, the previous delete operation hasn't always completed.
This is backed-up with the fact that if I put a breakpoint immediately after the delete operation, and manually run a curl request to look at the index that I tried to delete, I find that it's still there some of the time; on those occasions the error above appears if I continue the test.
I've tried asserting the isAcknowledged() method of the response to the delete operation, but that always returns true, even in cases when the error occurs.
I've also tried doing an exists() check before the create operation. Interestingly in that case if I run the tests without breakpoints, the exists() check always returns false (i.e. that the index doesn't exist) even in cases where the error will then occur, but if I put a breakpoint in before the create operation, then the exists() check returns true in cases where the error will happen.
I'm at a bit of a loss. As far as I understand, my requests should be synchronous, and from a comment on this question, this should mean that the delete() operation only returns when the index has definitely been deleted.
I suspect a key part of the problem might be that these tests are running on a cluster of 3 nodes. In setting up the client, I'm only addressing one of the nodes:
client = new RestHighLevelClient(RestClient.builder(new HttpHost("example.com", 9200, "https")));
but I can see that each operation is being replicated to the other two nodes.
When I stop a breakpoint before the create operation, in cases where the index is not deleted, I can see that it's not being deleted on any of the nodes, and it seems not to matter how long I wait, it never gets deleted.
Is there some way I can reliably determine whether the index has been deleted before I create it? Or perhaps something I need to do before I attempt the delete operation, to guarantee that it will succeed?

Hey I think there are quite a few things to think about. For one I'd test everything with curl or some kind of rest client till I start doing anything in code. Might just help you conceptually, but that's just my opinion.
This is one thing you should consider:
"If an external versioning variant is used, the delete operation automatically creates an index if it has not been created before (check out the create index API for manually creating an index)."
https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-delete.html
Which kind of would explain why exists() would return false. So if external versioning variant is used then the delete option would actually create an index with the same name prior to deleting it.
You mentioned about the fact that you are working with a three node cluster. Something you can try is:
"When making delete requests, you can set the wait_for_active_shards parameter to require a minimum number of shard copies to be active before starting to process the delete request." Here is a super detailed explanation which is certainly worth reading: https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-index_.html#index-wait-for-active-shards
I suggest you try:
curl -X DELETE 127.0.0.1:9200/fooindex?wait_for_active_shards=3
You said you have 3 nodes in your cluster,so this means that:"...indexing operation will require 3 active shard copies before proceeding, a requirement which should be met because there are 3 active nodes in the cluster, each one holding a copy of the shard."
This check is probably not 100% water tight since according to the docs here:https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-index_.html#index-wait-for-active-shards
"It is important to note that this setting greatly reduces the chances of the write operation not writing to the requisite number of shard copies, but it does not completely eliminate the possibility, because this check occurs before the write operation commences. Once the write operation is underway, it is still possible for replication to fail on any number of shard copies but still succeed on the primary. The _shards section of the write operation’s response reveals the number of shard copies on which replication succeeded/failed." so perhaps use this parameter, but have your code check the response to see if any operations failed.
Something you can also try is:
(I can't seem to find good documentation to back this info up)
This should be able to tell you if the cluster isn't ready to accept deletes.
curl -X DELETE 127.0.0.1:9200/index?wait_for_completion=true

Java Cucumber: creating scenario outlines with dynamic examples

We have a test where basically we need to input a specific value in a web site and make sure another value comes out. The data of the input-output for this is stored in an XML file.
Now we can create a single Scenario that runs once and loops through, submitting each value however we run into some reporting problems, if 2 out of 100 pairs fail we want to know which ones and not just have an assertion error for the whole scenario.
We would get much clearer reporting using a Scenario Outline where all the values are in the examples table. then the scenario itself runs repeatedly and we can fail an individual set as an assertion error and have that kick back clearly in a report.
Problem: we do not want to hard code all the values from the xml into the .feature. it's noisy but also if the values change it's slow to update. we would rather just provide the XML parse it and go, if things change we just drop in an updated XML.
Is there a way to create dynamic examples where we can run the scenario repeatedly, one for each data case, without explicitly defining it in the examples table ?

Using Cucumber for this is a bad idea. You should test this functionality lower down your stack with a unit test.
At some point in your code, after the user has input their value, the value will be passed to a method/function that will return your answer. This is the place to do this sort of testing.
A cucumber test going through the whole stack will upwards of 3 orders of magnitude slower than a well written unit tests. So you could test thousands of pairs of values in your unit test in the time it takes to run one single cuke.
If you do this sort of testing in Cucumber you will quickly end up with a test suite that takes far too long to run, or that can only be run quickly at great expense. This is very damaging to a project.
Cuking should be about one happy path (The user can enter a value and see the result) and maybe a sad path (the user enters a bad value and sees an error/explanation). Anything else needs to be pushed down to unit tests.

The NoraUi framework does exactly what you want to do in your project. The NoraUi code is open source. If you have questions about this framework, you can post an issue with the tag "Question"

Vaadin with Spring and Redis loads previous UI state on slow environment

I successfully enabled redis in a spring boot + vaadin application and it runs fine on my computer. The application is on a test run in a slower environment and an error occours multiple times.
WARN c.v.s.communication.ServerRpcHandler [ServerRpcHandler.java : 266] - Unexpected message id from the client. Expected: 248, got: 249
It seems like it happens when the serialization/deserialization of the VaadinSession takes too long. For example I have a page that has multiple checkboxes. I click on the first, then the second and third. After this the upper warn is thrown and a previous state of the page appears. In this case it might be without any cheched checkboxes or with one or two checked checkboxes. In rare cases it works properly.
I can't think of a solution for the problem. One thing I tried is showing a loading indicator immediately (100ms) (the default is after 300ms of loading) but it doesn't solve the problem.
Can I somehow configure when the serialization/deserialization occurs instead of every UI change or make it faster by leaving parts of the VaadinSession out of it? (I need the data on the current page so I can't make the ui components transient.)

We had a discussion about the problem in my workplace and we think that the components are working properly. The problem occurs when a serialization is slower then the next request's deserialization. (Every UI change begins with a deserialization to get the latest state then serializes the modified state.) My solution was creating an aspect that stores the latest VaadinSession that was sent for serialization and compares every deserialized VaadinSession to the stored one. I keep the one with the higher lastProcessedClientToServerId. This solves the issue almost every time.

JBehave steps makred as PENDING randomly

Heyy!
I have a bunch of story files with some scenarios, calling a WSDL service and checking the answer. The step functions have been written properly (as in no exceptions are thrown and it asserts true when it has to and vv.) and the service returns a valid answer.
My problem is in the case of some scenarios, I get steps (which has been defined as And in the story file, after a Given, or a Then) are getting marked as Pending, still IntelliJ puts the same green tick besides it as any other successful step.
The next time I run the test then they usually aren't pending anymore, but these marks coming and going randomly, which is kinda annoying, because I can't be sure if the step has actually been called or if it had any effect.
I can't show a code unfortunately, but one guess of mine is in the case of Given steps I just collect a number of Condition<>-s (from AssertJ) and don't actually do an assertion in the given step, but assert them all in the one and only When step.

Integration test elastic search, timing issue, document not found

I have an integration test, in java, of a facade that does a few things, among which is an index operation into an elastic search database. This elastic search database has been very naively set up (out of the box stuff actually, I'm in the learning fase).
The insertion is done, inside that facade, with the java api, also very naively, with the example nearly completely copy pasted from elastic search, as described here : http://www.elasticsearch.org/guide/reference/java-api/index_.html.
Afterwards I test a whether my facade did its stuff correctly, part of it is checking whether that document has really been inserted in the database. This I do, again, in the way elastic describes on their site : http://www.elasticsearch.org/guide/reference/java-api/search.html. I insert a document with a certain payload and look it up the same way.
This test works if I run in debug and set a breakpoint after facade did it's stuff, but it fails with no results found if I don't put this breakpoint or do not run in debug. This makes me think I'm really doing something wrong. Also, the application itself works (inserts and so on), so there's likely something wrong with my integration test, and not with my copy pasted code.
I guess that after the indexing operation returns the indexing is not really finished yet, or there is some replication going on that doesn't complete before the search, or something like that, but it eludes me what exactly and I can't seem to get it solved either.
I didn't try to put elastic on one node and one shard yet, maybe there's something wrong there, but I don't really see what exactly, so I didn't walk that path yet.
Like I said, just started using elastic so I might be missing something crucial and beginner-style. I can paste my exact code if needs be, but like I said it boils down to using two code snippets from the elastic search site in a test.
Kasper

Elasticsearch doesn't make data available immediately after the index operation is called. It waits for 1 sec by default for more data to arrive. However, you can force elasticsearch to make all data available immediately by calling refresh:
client.admin().indices().refresh(refreshRequest()).actionGet();
Try adding this operation after your facade is done indexing before you check the final result.

Unable to find refreshRequest method. I have used something like this and it seems to working now. I will do some more tests
client.admin().indices().refresh(new RefreshRequest(indexName)).actionGet();
where indexName is the String name of index to be refreshed