* Use Druid's extension loading for integration test instead of maven
* fix maven command
* override config path
* load input format extensions and kafka by default; add prepopulated-data group
* all docker-composes are overridable
* fix s3 configs
* override config for all
* fix docker_compose_args
* fix security tests
* turn off debug logs for overlord api calls
* clean up stuff
* revert docker-compose.yml
* fix override config for query error test; fix circular dependency in docker compose
* add back some dependencies in docker compose
* new maven profile for integration test
* example file filter
* Make nodeRole available during binding; add support for dynamic registration of DruidService
* fix checkstyle and test
* fix customRole test
* address comments
* add more javadoc
under "Aggregators", about the lgK setting, it said "Must be a power of 2 from 4 to 21 inclusively." 21 is not a power of 2, nor is 12, the given default. I think there may have been confusion because lgK represents log2 of K. We could say "K must be a power of 2...", or just say lgK must be between 4 and 21.
* Support routing data through an HTTP proxy
* Support routing data through an HTTP proxy
This adds the ability for the HttpClient to connect through an HTTP proxy. We
augment the channel factory to check if it is supposed to be proxied and, if so,
we connect to the proxy host first, issue a CONNECT command through to the final
recipient host and *then* give the channel to the normal http client for usage.
* add docs
* address comments
Co-authored-by: imply-cheddar <86940447+imply-cheddar@users.noreply.github.com>
Enhanced the ExtractionNamespace interface in lookups-cached-global core extension with the ability to set a maxHeapPercentage for the cache of the respective namespace. The reason for adding this functionality, is make it easier to detect when a lookup table grows to a size that the underlying service cannot handle, because it does not have enough memory. The default value of maxHeap for the interface is -1, which indicates that no maxHeapPercentage has been set. For the JdbcExtractionNamespace and UriExtractionNamespace implementations, the default value is null, which will cause the respective service that the lookup is loaded in, to warn when its cache is beyond mxHeapPercentage of the service's configured max heap size. If a positive non-null value is set for the namespace's maxHeapPercentage config, this value will be honored for all services that the respective lookup is loaded onto, and consequently log warning messages when the cache of the respective lookup grows beyond this respective percentage of the services configured max heap size. Warnings are logged every time that either Uri based or Jdbc based lookups are regenerated, if the maxHeapPercentage constraint is violated. No other implementations will log warnings at this time. No error is thrown when the size exceeds the maxHeapPercentage at this time, as doing so could break functionality for existing users. Previously the JdbcCacheGenerator generated its cache by materializing all rows of the underling table in memory at once; this made it difficult to log warning messages in the case that the results from the jdbc query were very large and caused the service to run out of memory. To help with this, this pr makes it so that the jdbc query results are instead streamed through an iterator.
Add support for hadoop 3 profiles . Most of the details are captured in #11791 .
We use a combination of maven profiles and resource filtering to achieve this. Hadoop2 is supported by default and a new maven profile with the name hadoop3 is created. This will allow the user to choose the profile which is best suited for the use case.
### Description
Today we ingest a number of high cardinality metrics into Druid across dimensions. These metrics are rolled up on a per minute basis, and are very useful when looking at metrics on a partition or client basis. Events is another class of data that provides useful information about a particular incident/scenario inside a Kafka cluster. Events themselves are carried inside kafka payload, but nonetheless there are some very useful metadata that is carried in kafka headers that can serve as useful dimension for aggregation and in turn bringing better insights.
PR(https://github.com/apache/druid/pull/10730) introduced support of Kafka headers in InputFormats.
We still need an input format to parse out the headers and translate those into relevant columns in Druid. Until that’s implemented, none of the information available in the Kafka message headers would be exposed. So first there is a need to write an input format that can parse headers in any given format(provided we support the format) like we parse payloads today. Apart from headers there is also some useful information present in the key portion of the kafka record. We also need a way to expose the data present in the key as druid columns. We need a generic way to express at configuration time what attributes from headers, key and payload need to be ingested into druid. We need to keep the design generic enough so that users can specify different parsers for headers, key and payload.
This PR is designed to solve the above by providing wrapper around any existing input formats and merging the data into a single unified Druid row.
Lets look at a sample input format from the above discussion
"inputFormat":
{
"type": "kafka", // New input format type
"headerLabelPrefix": "kafka.header.", // Label prefix for header columns, this will avoid collusions while merging columns
"recordTimestampLabelPrefix": "kafka.", // Kafka record's timestamp is made available in case payload does not carry timestamp
"headerFormat": // Header parser specifying that values are of type string
{
"type": "string"
},
"valueFormat": // Value parser from json parsing
{
"type": "json",
"flattenSpec": {
"useFieldDiscovery": true,
"fields": [...]
}
},
"keyFormat": // Key parser also from json parsing
{
"type": "json"
}
}
Since we have independent sections for header, key and payload, it will enable parsing each section with its own parser, eg., headers coming in as string and payload as json.
KafkaInputFormat will be the uber class extending inputFormat interface and will be responsible for creating individual parsers for header, key and payload, blend the data resolving conflicts in columns and generating a single unified InputRow for Druid ingestion.
"headerFormat" will allow users to plug parser type for the header values and will add default header prefix as "kafka.header."(can be overridden) for attributes to avoid collision while merging attributes with payload.
Kafka payload parser will be responsible for parsing the Value portion of the Kafka record. This is where most of the data will come from and we should be able to plugin existing parser. One thing to note here is that if batching is performed, then the code is augmenting header and key values to every record in the batch.
Kafka key parser will handle parsing Key portion of the Kafka record and will ingest the Key with dimension name as "kafka.key".
## KafkaInputFormat Class:
This is the class that orchestrates sending the consumerRecord to each parser, retrieve rows, merge the columns into one final row for Druid consumption. KafkaInputformat should make sure to release the resources that gets allocated as a part of reader in CloseableIterator<InputRow> during normal and exception cases.
During conflicts in dimension/metrics names, the code will prefer dimension names from payload and ignore the dimension either from headers/key. This is done so that existing input formats can be easily migrated to this new format without worrying about losing information.
* Configurable maxStreamLength for doubles sketches
* fix equals/hashcode and it test failure
* fix test
* fix it test
* benchmark
* doc
* grouping key
* fix comment
* dependency check
* Update docs/development/extensions-core/datasketches-quantiles.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Add prometheus-emitter docs
* Update docs/development/extensions.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
This change updates doc to clarify when and how a change to druid.auth.authenticator.basic.credentialIterations takes effect: changes apply only to new users or existing users upon changing their password via the credentials API, which may not be the expectation.
* HLL lgK and a tip
Knowledge transfer from https://the-asf.slack.com/archives/CJ8D1JTB8/p1600699967024200. Attempted to make a connection between the SQL HLL function and the HLL underneath without getting too complicated. Also added a note about using K over 16 being pretty much pointless.
* Corrected spelling
* Create datasketches-hll.md
Put roll-up back to rollup
* Update docs/development/extensions-core/datasketches-hll.md
Co-authored-by: Abhishek Agarwal <1477457+abhishekagarwal87@users.noreply.github.com>
Co-authored-by: Abhishek Agarwal <1477457+abhishekagarwal87@users.noreply.github.com>
This PR splits current SegmentLoader into SegmentLoader and SegmentCacheManager.
SegmentLoader - this class is responsible for building the segment object but does not expose any methods for downloading, cache space management, etc. Default implementation delegates the download operations to SegmentCacheManager and only contains the logic for building segments once downloaded. . This class will be used in SegmentManager to construct Segment objects.
SegmentCacheManager - this class manages the segment cache on the local disk. It fetches the segment files to the local disk, can clean up the cache, and in the future, support reserve and release on cache space. [See https://github.com/Make SegmentLoader extensible and customizable #11398]. This class will be used in ingestion tasks such as compaction, re-indexing where segment files need to be downloaded locally.
* Avro union support
* Document new union support
* Add support for AvroStreamInputFormat and fix checkstyle
* Extend multi-member union test schema and format
* Some additional docs and add Enums to spelling
* Rename explodeUnions -> extractUnions
* explode -> extract
* ByType
* Correct spelling error
* allow user to set group.id for Kafka ingestion task
* fix test coverage by removing deprecated code and add doc
* fix typo
* Update docs/development/extensions-core/kafka-ingestion.md
Co-authored-by: frank chen <frankchen@apache.org>
Co-authored-by: frank chen <frankchen@apache.org>
* request logs through kafka emitter
* travis fixes
* review comments
* kafka emitter unit test
* new line
* travis checks
* checkstyle fix
* count request lost when request topic is null
* prometheus-emitter
* use existing jetty server to expose prometheus collection endpoint
* unused variables
* better variable names
* removed unused dependencies
* more metric definitions
* reorganize
* use prometheus HTTPServer instead of hooking into Jetty server
* temporary empty help string
* temporary non-empty help. fix incorrect dimension value in JSON (also updated statsd json)
* added full help text. added metric conversion factor for timers that are not using seconds. Correct metric dimension name in documentation
* added documentation for prometheus emitter
* safety for invalid labelNames
* fix travis checks
* Unit test and better sanitization of metrics names and label values
* add precondition to check namespace against regex
* use precompiled regex
* remove static imports. fix metric types
* better docs. fix possible NPE in PrometheusEmitterConfig. Guard against multiple calls to PrometheusEmitter.start()
* Update regex for label-value replacements to allow internal numeric values. Additional tests
* Adds missing license header
updates website/.spelling to add words used in prometheus-emitter docs.
updates docs/operations/metrics.md to correct the spelling of
bufferPoolName
* fixes version in extensions-contrib/prometheus-emitter
* fix style guide errors
* update import ordering
* add another word to website/.spelling
* remove unthrown declared exception
* remove unused import
* Pushgateway strategy for metrics
* typo
* Format fix and nullable strategy
* Update pom file for prometheus-emitter
* code review comments. Counter to gauge for cache metrics, periodical task to pushGateway
* Syntax fix
* Dimension label regex include numeric character back, fix previous commit
* bump prometheus-emitter pom dev version
* Remove scheduled task inside poen that push metrics
* Fix checkstyle
* Unit test coverage
* Unit test coverage
* Spelling
* Doc fix
* spelling
Co-authored-by: Michael Schiff <michael.schiff@tubemogul.com>
Co-authored-by: Michael Schiff <schiff.michael@gmail.com>
Co-authored-by: Tianxin Zhao <tianxin.zhao@tubemogul.com>
Co-authored-by: Tianxin Zhao <tizhao@adobe.com>
* druid task auto scale based on kafka lag
* fix kafkaSupervisorIOConfig and KinesisSupervisorIOConfig
* druid task auto scale based on kafka lag
* fix kafkaSupervisorIOConfig and KinesisSupervisorIOConfig
* test dynamic auto scale done
* auto scale tasks tested on prd cluster
* auto scale tasks tested on prd cluster
* modify code style to solve 29055.10 29055.9 29055.17 29055.18 29055.19 29055.20
* rename test fiel function
* change codes and add docs based on capistrant reviewed
* midify test docs
* modify docs
* modify docs
* modify docs
* merge from master
* Extract the autoScale logic out of SeekableStreamSupervisor to minimize putting more stuff inside there && Make autoscaling algorithm configurable and scalable.
* fix ci failed
* revert msic.xml
* add uts to test autoscaler create && scale out/in and kafka ingest with scale enable
* add more uts
* fix inner class check
* add IT for kafka ingestion with autoscaler
* add new IT in groups=kafka-index named testKafkaIndexDataWithWithAutoscaler
* review change
* code review
* remove unused imports
* fix NLP
* fix docs and UTs
* revert misc.xml
* use jackson to build autoScaleConfig with default values
* add uts
* use jackson to init AutoScalerConfig in IOConfig instead of Map<>
* autoscalerConfig interface and provide a defaultAutoScalerConfig
* modify uts
* modify docs
* fix checkstyle
* revert misc.xml
* modify uts
* reviewed code change
* reviewed code change
* code reviewed
* code review
* log changed
* do StringUtils.encodeForFormat when create allocationExec
* code review && limit taskCountMax to partitionNumbers
* modify docs
* code review
Co-authored-by: yuezhang <yuezhang@freewheel.tv>
* add offsetFetchPeriod to kinesis ingestion doc
* Remove jackson dependencies from extensions
* Use fixed delay for lag collection
* Metrics reset after finishing processing
* comments
* Broaden the list of exceptions to retry for
* Unit tests
* Add more tests
* Refactoring
* re-order metrics
* Doc suggestions
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
* Add tests
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
* zk-less druid cluster in k8s build
* attempt to fix build and use http based remote task management
* mm/router logs for debugging
* add default account k8s role and binding for pod, configMap access
* fix issue
* change router port to 8088 for common readinessProbe
* break build_run_k8s_cluster.sh into separate scripts
* revert changes to K8sDruidNodeAnnouncer.java
* k8s extension doc update
* add license to new file
* address review comments
* do not try to load lookups at startup to improve cluster startup time
* Add https to druid-influxdb-emitter extension
* address CI failures
* increase test coverage
* tests for being unable to load trustStore
* fix EqualsVerifier test
* fix intellij inspection error
* use try-with-resources when loading trustStore
* Fix Avro OCF detection prefix and run formation detection on raw input
* Support Avro Fixed and Enum types correctly
* Check Avro version byte in format detection
* Add test for AvroOCFReader.sample
Ensures that the Sampler doesn't receive raw input that it can't
serialize into JSON.
* Document Avro type handling
* Add TS unit tests for guessInputFormat
* support redis cluster
* add 'password', 'database' properties
* test cases passed
* update doc
* some improvements
* fix CI
* add more test cases to improve branch coverage
* fix dependency check for test
* resolve review comments
* Add note about aggreations on floats
Floating point math is known to be unstable. Due to the way aggregators work
across segments it's possible for the same query operating on the same data to
produce slightly different results.
The same problem exists with any aggregators that are not commutative since
the merge order across segments is not guaranteed.
* Also talk about doubles
* Apply suggestions from code review
* init commit, all tests passed
* fix format
Signed-off-by: frank chen <frank.chen021@outlook.com>
* data stored successfully
* modify config path
* add doc
* add aliyun-oss extension to project
* remove descriptor deletion code to avoid warning message output by aliyun client
* fix warnings reported by lgtm-com
* fix ci warnings
Signed-off-by: frank chen <frank.chen021@outlook.com>
* fix errors reported by intellj inspection check
Signed-off-by: frank chen <frank.chen021@outlook.com>
* fix doc spelling check
Signed-off-by: frank chen <frank.chen021@outlook.com>
* fix dependency warnings reported by ci
Signed-off-by: frank chen <frank.chen021@outlook.com>
* fix warnings reported by CI
Signed-off-by: frank chen <frank.chen021@outlook.com>
* add package configuration to support showing extension info
Signed-off-by: frank chen <frank.chen021@outlook.com>
* add IT test cases and fix bugs
Signed-off-by: frank chen <frank.chen021@outlook.com>
* 1. code review comments adopted
2. change schema from 'aliyun-oss' to 'oss'
Signed-off-by: frank chen <frank.chen021@outlook.com>
* add license info
Signed-off-by: frank chen <frank.chen021@outlook.com>
* fix doc
Signed-off-by: frank chen <frank.chen021@outlook.com>
* exclude execution of IT testcases of OSS extension from CI
Signed-off-by: frank chen <frank.chen021@outlook.com>
* put the extensions under contrib group and add to distribution
* fix names in test cases
* add unit test to cover OssInputSource
* fix names in test cases
* fix dependency problem reported by CI
Signed-off-by: frank chen <frank.chen021@outlook.com>
* Update data-formats.md
Per Suneet, "Since you're editing this file can you also fix the json on line 177 please - it's missing a comma after the }"
* Light text cleanup
* Removing discussion of sample data, since it's repeated in the data loading tutorial, and not immediately relevant here.
* Clarifying accepted values for URI lookup
* Update index.md
* original quickstart full first pass
* original quickstart full first pass
* first pass all the way through
* straggler
* image touchups and finished old tutorial
* a bit of finishing up
* druid-caffeine-cache ext previously removed
* Sample MaxDirectMemorySize value unrealistic
* Review comments
* fixing links
* spell checking gymnastics
* workerThreads desc slightly expanded
* typo
* Typo
* Reversing Kafka config order
* Changing order of configs for Kinesis
* Trying this again: ioConfig then tuningConfig
* Adding support for autoscaling in GCE
* adding extra google deps also in gce pom
* fix link in doc
* remove unused deps
* adding terms to spelling file
* version in pom 0.17.0-incubating-SNAPSHOT --> 0.18.0-SNAPSHOT
* GCEXyz -> GceXyz in naming for consistency
* add preconditions
* add VisibleForTesting annotation
* typos in comments
* use StringUtils.format instead of String.format
* use custom exception instead of exit
* factorize interval time between retries
* making literal value a constant
* iter all network interfaces
* use provided on google (non api) deps
* adding missing dep
* removing unneded this and use Objects methods instead o 3-way if in hash and comparison
* adding import
* adding retries around getRunningInstances and adding limit for operation end waiting
* refactor GceEnvironmentConfig.hashCode
* 0.18.0-SNAPSHOT -> 0.19.0-SNAPSHOT
* removing unused config
* adding tests to hash and equals
* adding nullable to waitForOperationEnd
* adding testTerminate
* adding unit tests for createComputeService
* increasing retries in unrelated integration-test to prevent sporadic failure (hopefully)
* reverting queryResponseTemplate change
* adding comment for Compute.Builder.build() returning null
* Refresh query docs.
Larger changes:
- New doc: querying/datasource.md describes the various kinds of
datasources you can use, and has examples for both SQL and native.
- New doc: querying/query-execution.md describes how native queries
are executed at a high level. It doesn't go into the details of specific
query engines or how queries run at a per-segment level. But I think it
would be good to add or link that content here in the future.
- Refreshed doc: querying/sql.md updated to refer to joins, reformatted
a bit, added a new "Query translation" section that explains how
queries are translated from SQL to native, and removed configuration
details (moved to configuration/index.md).
- Refreshed doc: querying/joins.md updated to refer to join datasources.
Smaller changes:
- Add helpful banners to the top of query documentation pages telling
people whether a given page describes SQL, native, or both.
- Add SQL metrics to operations/metrics.md.
- Add some color and cross-links in various places.
- Add native query component docs to the sidebar, and renamed them so
they look nicer.
- Remove Select query from the sidebar.
- Fix Broker SQL configs in configuration/index.md. Remove them from
querying/sql.md.
- Combined querying/searchquery.md and querying/searchqueryspec.md.
* Updates.
* Fix numbering.
* Fix glitches.
* Add new words to spellcheck file.
* Assorted changes.
* Further adjustments.
* Add missing punctuation.
* Document possible vulnerabilities for the druid-ranger-security
In certain configurations the ranger plugin can expose vulnerabilities due
to some of its dependencies having CVEs.
* Spelling checker is a bit tight
* kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* Kinesis IT
* fix kinesis timeout
* Kinesis IT
* Kinesis IT
* fix checkstyle
* Kinesis IT
* address comments
* fix checkstyle
* druid pac4j security extension for OpenID Connect OAuth 2.0 authentication
* update version in druid-pac4j pom
* introducing unauthorized resource filter
* authenticated but authorized /unified-webconsole.html
* use httpReq.getRequestURI() for matching callback path
* add documentation
* minor doc addition
* licesne file updates
* make dependency analyze succeed
* fix doc build
* hopefully fixes doc build
* hopefully fixes license check build
* yet another try on fixing license build
* revert unintentional changes to website folder
* update version to 0.18.0-SNAPSHOT
* check session and its expiry on each request
* add crypto service
* code for encrypting the cookie
* update doc with cookiePassphrase
* update license yaml
* make sessionstore in Pac4jFilter private non static
* make Pac4jFilter fields final
* okta: use sha256 for hmac
* remove incubating
* add UTs for crypto util and session store impl
* use standard charsets
* add license header
* remove unused file
* add org.objenesis.objenesis to license.yaml
* a bit of nit changes in CryptoService and embedding EncryptionResult for clarity
* rename alg to cipherAlgName
* take cipher alg name, mode and padding as input
* add java doc for CryptoService and make it more understandable
* another UT for CryptoService
* cache pac4j Config
* use generics clearly in Pac4jSessionStore
* update cookiePassphrase doc to mention PasswordProvider
* mark stuff Nullable where appropriate in Pac4jSessionStore
* update doc to mention jdbc
* add error log on reaching callback resource
* javadoc for Pac4jCallbackResource
* introduce NOOP_HTTP_ACTION_ADAPTER
* add correct module name in license file
* correct extensions folder name in licenses.yaml
* replace druid-kubernetes-extensions to druid-pac4j
* cache SecureRandom instance
* rename UnauthorizedResourceFilter to AuthenticationOnlyResourceFilter
* Add support for optional cloud (aws, gcs, etc.) credentials for s3 for ingestion
* Add support for optional cloud (aws, gcs, etc.) credentials for s3 for ingestion
* Add support for optional cloud (aws, gcs, etc.) credentials for s3 for ingestion
* fix build failure
* fix failing build
* fix failing build
* Code cleanup
* fix failing test
* Removed CloudConfigProperties and make specific class for each cloudInputSource
* Removed CloudConfigProperties and make specific class for each cloudInputSource
* pass s3ConfigProperties for split
* lazy init s3client
* update docs
* fix docs check
* address comments
* add ServerSideEncryptingAmazonS3.Builder
* fix failing checkstyle
* fix typo
* wrap the ServerSideEncryptingAmazonS3.Builder in a provider
* added java docs for S3InputSource constructor
* added java docs for S3InputSource constructor
* remove wrap the ServerSideEncryptingAmazonS3.Builder in a provider
* Move Azure extension into Core
Moving the azure extension into Core.
* * Fix build failure
* * Add The MIT License (MIT) to list of compatible licenses
* * Address review comments
* * change reference to contrib azure to core azure
* * Fix spelling mistakes.
* Add common optional dependencies for extensions
Include hadoop-aws and postgres JDBC connector jar to improve
out-of-the-box experience for extensions. The mysql JDBC connector jar
is not bundled as it is GPL.
* Update docs
* Fix typo
* Add Azure config options for segment prefix and max listing length
Added configuration options to allow the user to specify the prefix
within the segment container to store the segment files. Also
added a configuration option to allow the user to specify the
maximum number of input files to stream for each iteration.
* * Fix test failures
* * Address review comments
* * add dependency explicitly to pom
* * update docs
* * Address review comments
* * Address review comments
* Add config option for namespacePrefix
opentsdb emitter sends metric names to opentsdb verbatim as what druid
names them, for example "query.count", this doesn't fit well with a
central opentsdb server which might have namespaced metrics, for example
"druid.query.count". This adds support for adding an optional prefix.
The prefix also gets a trailing dot (.), after it, so the metric name
becomes <namespacePrefix>.<metricname>
configureable as "druid.emitter.opentsdb.namespacePrefix", as
documented.
Co-authored-by: Martin Gerholm <martin.gerholm@deltaprojects.com>
Signed-off-by: Martin Gerholm <martin.gerholm@deltaprojects.com>
Signed-off-by: Björn Zettergren <bjorn.zettergren@deltaprojects.com>
* Spelling for PR #9372
Added "namespacePrefix" to .spelling exceptions, it's a variable name
used in documentation for opentsdb-emitter.
* fixing tests for PR #9372
changed naming of variables to be more descriptive
added test of prefix being an empty string: "".
added a conditional to buildNamespacePrefix to check for empty string
being fed if EventConverter called without OpentsdbEmitterConfig
instance.
* fixing checkstyle errors for PR #9372
used == to compare literal string, should be equals()
* cleaned up and updated PR #9372
Created a buildMetric function as suggested by clintropolis, and
removed redundant tests for empty strings as they're only used when
calling EventConverter directly without going through
OpentsdbEmitterConfig.
* consistent naming of tests PR #9372
Changed names of tests in files to match better with what it was
actually testing
changed check for Strings.isNullOrEmpty to just check for `null`, as
empty string valued `namespacePrefix` is handled in
OpentsdbEmitterConfig.
Co-authored-by: Martin Gerholm <inspector-martin@users.noreply.github.com>