* Broker: Add ability to inline subqueries.
The main changes:
- ClientQuerySegmentWalker: Add ability to inline queries.
- Query: Add "getSubQueryId" and "withSubQueryId" methods.
- QueryMetrics: Add "subQueryId" dimension.
- ServerConfig: Add new "maxSubqueryRows" parameter, which is used by
ClientQuerySegmentWalker to limit how many rows can be inlined per
query.
- IndexedTableJoinMatcher: Allow creating keys on top of unknown types,
by assuming they are strings. This is useful because not all types are
known for fields in query results.
- InlineDataSource: Store RowSignature rather than component parts. Add
more zealous "equals" and "hashCode" methods to ease testing.
- Moved QuerySegmentWalker test code from CalciteTests and
SpecificSegmentsQueryWalker in druid-sql to QueryStackTests in
druid-server. Use this to spin up a new ClientQuerySegmentWalkerTest.
* Adjustments from CI.
* Fix integration test.
* Move RowSignature from druid-sql to druid-processing and make use of it.
1) Moved (most of) RowSignature from sql to processing. Left behind the SQL-specific
stuff in a RowSignatures utility class. It also picked up some new convenience
methods along the way.
2) There were a lot of places in the code where Map<String, ValueType> was used to
associate columns with type info. These are now all replaced with RowSignature.
3) QueryToolChest's resultArrayFields method is replaced with resultArraySignature,
and it now provides type info.
* Fix up extensions.
* Various fixes
* Link up row-based datasources to serving layer.
- Add SegmentWrangler interface that allows linking of DataSources to Segments.
- Add LocalQuerySegmentWalker that uses SegmentWranglers to compute queries on
data that is available locally.
- Modify ClientQuerySegmentWalker to use LocalQuerySegmentWalker when the base
datasource is concrete and not a table.
- Add SegmentWranglerModule to the Broker so it has them available and can
properly instantiate . LocalQuerySegmentWalkers.
- Set InlineDataSource and LookupDataSource to concrete, since they can be
directly queried now.
* Fix tests.
* Harmonization and bug-fixing for selector and filter behavior on unknown types.
- Migrate ValueMatcherColumnSelectorStrategy to newer ColumnProcessorFactory
system, and set defaultType COMPLEX so unknown types can be dynamically matched.
- Remove ValueGetters in favor of ColumnComparisonFilter doing its own thing.
- Switch various methods to use convertObjectToX when casting to numbers, rather
than ad-hoc and inconsistent logic.
- Fix bug in RowBasedExpressionColumnValueSelector: isBindingArray should return
true even for 0- or 1- element arrays.
- Adjust various javadocs.
* Add throwParseExceptions option to Rows.objectToNumber, switch back to that.
* Update tests.
* Adjust moment sketch tests.
* 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.
* Create splits of multiple files for parallel indexing
* fix wrong import and npe in test
* use the single file split in tests
* rename
* import order
* Remove specific local input source
* Update docs/ingestion/native-batch.md
Co-Authored-By: sthetland <steve.hetland@imply.io>
* Update docs/ingestion/native-batch.md
Co-Authored-By: sthetland <steve.hetland@imply.io>
* doc and error msg
* fix build
* fix a test and address comments
Co-authored-by: sthetland <steve.hetland@imply.io>
* 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>
* Run IntelliJ inspections on Travis
Running IntelliJ inspections currently takes about 90 minutes, but they
can be run in about 30 minutes on Travis.
* Restore assert statements
* IMPLY-1946: Improve code quality and unit test coverage of the Azure extension
* Update unit tests to increase test coverage for the extension
* Clean up any messy code
* Enfore code coverage as part of tests.
* * Update azure extension pom to remove unnecessary things
* update jacoco thresholds
* * updgrade version of azure-storage library version uses to
most upto-date version
* implement Azure InputSource reader and deprecate Azure FireHose
* implement azure InputSource reader
* deprecate Azure FireHose implementation
* * exclude common libraries that are included from druid core
* Implement more of Azure input source.
* * Add tests
* * Add more tests
* * deprecate azure firehose
* * added more tests
* * rollback fix for google cloud batch ingestion bug. Will be
fixed in another PR.
* * Added javadocs for all azure related classes
* Addressed review comments
* * Remove dependency on org.apache.commons:commons-collections4
* Fix LGTM warnings
* Add com.google.inject.extensions:guice-assistedinject to licenses
* * rename classes as suggested in review comments
* * Address review comments
* * Address review comments
* * Address review comments
* Guicify druid sql module
Break up the SQLModule in to smaller modules and provide a binding that
modules can use to register schemas with druid sql.
* fix some tests
* address code review
* tests compile
* Working tests
* Add all the tests
* fix up licenses and dependencies
* add calcite dependency to druid-benchmarks
* tests pass
* rename the schemas
* IMPLY-1946: Improve code quality and unit test coverage of the Azure extension
* Update unit tests to increase test coverage for the extension
* Clean up any messy code
* Enfore code coverage as part of tests.
* * Update azure extension pom to remove unnecessary things
* update jacoco thresholds
* * updgrade version of azure-storage library version uses to
most upto-date version
* * exclude common libraries that are included from druid core
* * address review comments
* SQL join support for lookups.
1) Add LookupSchema to SQL, so lookups show up in the catalog.
2) Add join-related rels and rules to SQL, allowing joins to be planned into
native Druid queries.
* Add two missing LookupSchema calls in tests.
* Fix tests.
* Fix typo.
* intelliJ inspections cleanup
- remove redundant escapes
- performance warnings
- access static member via instance reference
- static method declared final
- inner class may be static
Most of these changes are aesthetic, however, they will allow inspections to
be enabled as part of CI checks going forward
The valuable changes in this delta are:
- using StringBuilder instead of string addition in a loop
indexing-hadoop/.../Utils.java
processing/.../ByteBufferMinMaxOffsetHeap.java
- Use class variables instead of static variables for parameterized test
processing/src/.../ScanQueryLimitRowIteratorTest.java
* Add intelliJ inspection warnings as errors to druid profile
* one more static inner class
* Reconcile terminology and method naming to 'used/unused segments'; Don't use terms 'enable/disable data source'; Rename MetadataSegmentManager to MetadataSegments; Make REST API methods which mark segments as used/unused to return server error instead of an empty response in case of error
* Fix brace
* Import order
* Rename withKillDataSourceWhitelist to withSpecificDataSourcesToKill
* Fix tests
* Fix tests by adding proper methods without interval parameters to IndexerMetadataStorageCoordinator instead of hacking with Intervals.ETERNITY
* More aligned names of DruidCoordinatorHelpers, rename several CoordinatorDynamicConfig parameters
* Rename ClientCompactTaskQuery to ClientCompactionTaskQuery for consistency with CompactionTask; ClientCompactQueryTuningConfig to ClientCompactionTaskQueryTuningConfig
* More variable and method renames
* Rename MetadataSegments to SegmentsMetadata
* Javadoc update
* Simplify SegmentsMetadata.getUnusedSegmentIntervals(), more javadocs
* Update Javadoc of VersionedIntervalTimeline.iterateAllObjects()
* Reorder imports
* Rename SegmentsMetadata.tryMark... methods to mark... and make them to return boolean and the numbers of segments changed and relay exceptions to callers
* Complete merge
* Add CollectionUtils.newTreeSet(); Refactor DruidCoordinatorRuntimeParams creation in tests
* Remove MetadataSegmentManager
* Rename millisLagSinceCoordinatorBecomesLeaderBeforeCanMarkAsUnusedOvershadowedSegments to leadingTimeMillisBeforeCanMarkAsUnusedOvershadowedSegments
* Fix tests, refactor DruidCluster creation in tests into DruidClusterBuilder
* Fix inspections
* Fix SQLMetadataSegmentManagerEmptyTest and rename it to SqlSegmentsMetadataEmptyTest
* Rename SegmentsAndMetadata to SegmentsAndCommitMetadata to reduce the similarity with SegmentsMetadata; Rename some methods
* Rename DruidCoordinatorHelper to CoordinatorDuty, refactor DruidCoordinator
* Unused import
* Optimize imports
* Rename IndexerSQLMetadataStorageCoordinator.getDataSourceMetadata() to retrieveDataSourceMetadata()
* Unused import
* Update terminology in datasource-view.tsx
* Fix label in datasource-view.spec.tsx.snap
* Fix lint errors in datasource-view.tsx
* Doc improvements
* Another attempt to please TSLint
* Another attempt to please TSLint
* Style fixes
* Fix IndexerSQLMetadataStorageCoordinator.createUsedSegmentsSqlQueryForIntervals() (wrong merge)
* Try to fix docs build issue
* Javadoc and spelling fixes
* Rename SegmentsMetadata to SegmentsMetadataManager, address other comments
* Address more comments
Builds on #9235, using the datasource analysis functionality to replace various ad-hoc
approaches. The most interesting changes are in ClientQuerySegmentWalker (brokers),
ServerManager (historicals), and SinkQuerySegmentWalker (indexing tasks).
Other changes related to improving how we analyze queries:
1) Changes TimelineServerView to return an Optional timeline, which I thought made
the analysis changes cleaner to implement.
2) Added QueryToolChest#canPerformSubquery, which is now used by query entry points to
determine whether it is safe to pass a subquery dataSource to the query toolchest.
Fixes an issue introduced in #5471 where subqueries under non-groupBy-typed queries
were silently ignored, since neither the query entry point nor the toolchest did
anything special with them.
3) Removes the QueryPlus.withQuerySegmentSpec method, which was mostly being used in
error-prone ways (ignoring any potential subqueries, and not verifying that the
underlying data source is actually a table). Replaces with a new function,
Queries.withSpecificSegments, that includes sanity checks.
* Address security vulnerabilities CVSS >= 7
Update dependencies to address security vulnerabilities with CVSS scores
of 7 or higher. A new Travis CI job is added to prevent new
high/critical security vulnerabilities from being added.
Updated dependencies:
- api-util 1.0.0 -> 1.0.3
- jackson 2.9.10 -> 2.10.1
- kafka 2.1.0 -> 2.1.1
- libthrift 0.10.0 -> 0.13.0
- protobuf 3.2.0 -> 3.11.0
The following high/critical security vulnerabilities are currently
suppressed (so that the new Travis CI job can be added now) and are left
as future work to fix:
- hibernate-validator:5.2.5
- jackson-mapper-asl:1.9.13
- libthrift:0.6.1
- netty:3.10.6
- nimbus-jose-jwt:4.41.1
* Rename EDL1 license file
* Fix inspection errors
* add s3 input source for native batch ingestion
* add docs
* fixes
* checkstyle
* lazy splits
* fixes and hella tests
* fix it
* re-use better iterator
* use key
* javadoc and checkstyle
* exception
* oops
* refactor to use S3Coords instead of URI
* remove unused code, add retrying stream to handle s3 stream
* remove unused parameter
* update to latest master
* use list of objects instead of object
* serde test
* refactor and such
* now with the ability to compile
* fix signature and javadocs
* fix conflicts yet again, fix S3 uri stuffs
* more tests, enforce uri for bucket
* javadoc
* oops
* abstract class instead of interface
* null or empty
* better error
* Add FileUtils.createTempDir() and enforce its usage.
The purpose of this is to improve error messages. Previously, the error
message on a nonexistent or unwritable temp directory would be
"Failed to create directory within 10,000 attempts".
* Further updates.
* Another update.
* Remove commons-io from benchmark.
* Fix tests.
* Tidy up lifecycle, query, and ingestion logging.
The goal of this patch is to improve the clarity and usefulness of
Druid's logging for cluster operators. For more information, see
https://twitter.com/cowtowncoder/status/1195469299814555648.
Concretely, this patch does the following:
- Changes a lot of INFO logs to DEBUG, and DEBUG to TRACE, with the
goal of reducing redundancy and improving clarity by avoiding
showing rarely-useful log messages. This includes most "starting"
and "stopping" messages, and most messages related to individual
columns.
- Adds new log4j2 templates that show operators how to enabled DEBUG
logging for certain important packages.
- Eliminate stack traces for query errors, unless log level is DEBUG
or more. This is useful because query errors often indicate user
error rather than system error, but dumping stack trace often gave
operators the impression that there was a system failure.
- Adds task id to Appenderator, AppenderatorDriver thread names. In
the default log4j2 configuration, this will put them in log lines
as well. It's very useful if a user is using the Indexer, where
multiple tasks run in the same JVM.
- More consistent terminology when it comes to "sequences" (sets of
segments that are handed-off together by Kafka ingestion) and
"offsets" (cursors in partitions). These terms had been confused in
some log messages due to the fact that Kinesis calls offsets
"sequence numbers".
- Replaces some ugly toString calls with either the JSONification or
something more operator-accessible (like a URL or segment identifier,
instead of JSON object representing the same).
* Adjustments.
* Adjust integration test.
* sketch of broker parallel merges done in small batches on fork join pool
* fix non-terminating sequences, auto compute parallelism
* adjust benches
* adjust benchmarks
* now hella more faster, fixed dumb
* fix
* remove comments
* log.info for debug
* javadoc
* safer block for sequence to yielder conversion
* refactor LifecycleForkJoinPool into LifecycleForkJoinPoolProvider which wraps a ForkJoinPool
* smooth yield rate adjustment, more logs to help tune
* cleanup, less logs
* error handling, bug fixes, on by default, more parallel, more tests
* remove unused var
* comments
* timeboundary mergeFn
* simplify, more javadoc
* formatting
* pushdown config
* use nanos consistently, move logs back to debug level, bit more javadoc
* static terminal result batch
* javadoc for nullability of createMergeFn
* cleanup
* oops
* fix race, add docs
* spelling, remove todo, add unhandled exception log
* cleanup, revert unintended change
* another unintended change
* review stuff
* add ParallelMergeCombiningSequenceBenchmark, fixes
* hyper-threading is the enemy
* fix initial start delay, lol
* parallelism computer now balances partition sizes to partition counts using sqrt of sequence count instead of sequence count by 2
* fix those important style issues with the benchmarks code
* lazy sequence creation for benchmarks
* more benchmark comments
* stable sequence generation time
* update defaults to use 100ms target time, 4096 batch size, 16384 initial yield, also update user docs
* add jmh thread based benchmarks, cleanup some stuff
* oops
* style
* add spread to jmh thread benchmark start range, more comments to benchmarks parameters and purpose
* retool benchmark to allow modeling more typical heterogenous heavy workloads
* spelling
* fix
* refactor benchmarks
* formatting
* docs
* add maxThreadStartDelay parameter to threaded benchmark
* why does catch need to be on its own line but else doesnt
* IndexerSQLMetadataStorageCoordinator.getTimelineForIntervalsWithHandle() don't fetch abutting intervals; simplify getUsedSegmentsForIntervals()
* Add VersionedIntervalTimeline.findNonOvershadowedObjectsInInterval() method; Propagate the decision about whether only visible segmetns or visible and overshadowed segments should be returned from IndexerMetadataStorageCoordinator's methods to the user logic; Rename SegmentListUsedAction to RetrieveUsedSegmentsAction, SegmetnListUnusedAction to RetrieveUnusedSegmentsAction, and UsedSegmentLister to UsedSegmentsRetriever
* Fix tests
* More fixes
* Add javadoc notes about returning Collection instead of Set. Add JacksonUtils.readValue() to reduce boilerplate code
* Fix KinesisIndexTaskTest, factor out common parts from KinesisIndexTaskTest and KafkaIndexTaskTest into SeekableStreamIndexTaskTestBase
* More test fixes
* More test fixes
* Add a comment to VersionedIntervalTimelineTestBase
* Fix tests
* Set DataSegment.size(0) in more tests
* Specify DataSegment.size(0) in more places in tests
* Fix more tests
* Fix DruidSchemaTest
* Set DataSegment's size in more tests and benchmarks
* Fix HdfsDataSegmentPusherTest
* Doc changes addressing comments
* Extended doc for visibility
* Typo
* Typo 2
* Address comment
* remove select query
* thanks teamcity
* oops
* oops
* add back a SelectQuery class that throws RuntimeExceptions linking to docs
* adjust text
* update docs per review
* deprecated
* fix segment underReplicated/unavailable counts to be gauges instead of counters
* fix jvm/gc/cpu to be a counter instead of timre
jvm/gc/cpu represents the total cpu time spent for multiple gc
invocations, not the time spent in each gc cycle.
the number needs to be divided by jvm/gc/count to get the average gc
time per cycle
* update docs
* fix spellcheck
* Implementing dropwizard emitter for druid
making metric manager and alert emitters as optional
* Refactor and make things work
more improvements
improve docs
refactrings
* Fix teamcity inspections
* review comments
* more review comments
* add limit to max number of gauges
* update pom version
* fix pom
* review comments
* review comment
* review comments
* fix broken doc link
review comments
review comments
* review comments
* fix checkstyle
* more spell check fixes
* fix travis failures
* Fix dependency analyze warnings
Update the maven dependency plugin to the latest version and fix all
warnings for unused declared and used undeclared dependencies in the
compile scope. Added new travis job to add the check to CI. Also fixed
some source code files to use the correct packages for their imports and
updated druid-forbidden-apis to prevent regressions.
* Address review comments
* Adjust scope for org.glassfish.jaxb:jaxb-runtime
* Fix dependencies for hdfs-storage
* Consolidate netty4 versions
* Add realization for updating version of derived segments in MaterializedView
* add unit test, and change code style for the sake of ease of understanding
* LoggingEmitter: print event as json
* use DefaultRequestLogEventBuilderFactory in emitting request logger by default
* print context in query metric as json
* removed unused jsonMapper from DefaultQueryMetrics
* add comment
* remove change to DefaultRequestLogEventBuilderFactory.java
* Zookeeper version is updated.
* Zookeeper version is updated at licenses.yaml
* licenses.yaml is updated and dependencies are fixed to make the project successfully build.
* Zookeeper versions are fixed at licenses.yaml
* check ctyle for constant field name
* check ctyle for constant field name
* check ctyle for constant field name
* check ctyle for constant field name
* check ctyle for constant field name
* check ctyle for constant field name
* check ctyle for constant field name
* check ctyle for constant field name
* check ctyle for constant field name
* merging with upstream
* review-1
* unknow changes
* unknow changes
* review-2
* merging with master
* review-2 1 changes
* review changes-2 2
* bug fix
* Refactored ResponseContext and aggregated its keys into Enum
* Added unit tests for ResponseContext and refactored the serialization
* Removed unused methods
* Fixed code style
* Fixed code style
* Fixed code style
* Made SerializationResult static
* Updated according to the PR discussion:
Renamed an argument
Updated comparator
Replaced Pair usage with Map.Entry
Added a comment about quadratic complexity
Removed boolean field with an expression
Renamed SerializationResult field
Renamed the method merge to add and renamed several context keys
Renamed field and method related to scanRowsLimit
Updated a comment
Simplified a block of code
Renamed a variable
* Added JsonProperty annotation to renamed ScanQuery field
* Extension-friendly context key implementation
* Refactored ResponseContext: updated delegate type, comments and exceptions
Reducing serialized context length by removing some of its'
collection elements
* Fixed tests
* Simplified response context truncation during serialization
* Extracted a method of removing elements from a response context and
added some comments
* Fixed typos and updated comments
* GroupBy array-based result rows.
Fixes#8118; see that proposal for details.
Other than the GroupBy changes, the main other "interesting" classes are:
- ResultRow: The array-based result type.
- BaseQuery: T is no longer required to be Comparable.
- QueryToolChest: Adds "decorateObjectMapper" to enable query-aware serialization
and deserialization of result rows (necessary due to their positional nature).
- QueryResource: Uses the new decoration functionality.
- DirectDruidClient: Also uses the new decoration functionality.
- QueryMaker (in Druid SQL): Modifications to read ResultRows.
These classes weren't changed, but got some new javadocs:
- BySegmentQueryRunner
- FinalizeResultsQueryRunner
- Query
* Adjustments for TC stuff.
* Fix dependency analyze warnings
Update the maven dependency plugin to the latest version and fix all
warnings for unused declared and used undeclared dependencies in the
compile scope. Added new travis job to add the check to CI. Also fixed
some source code files to use the correct packages for their imports.
* Fix licenses and dependencies
* Fix licenses and dependencies again
* Fix integration test dependency
* Address review comments
* Fix unit test dependencies
* Fix integration test dependency
* Fix integration test dependency again
* Fix integration test dependency third time
* Fix integration test dependency fourth time
* Fix compile error
* Fix assert package
* add CachingClusteredClient benchmark, refactor some stuff
* revert WeightedServerSelectorStrategy to ConnectionCountServerSelectorStrategy and remove getWeight since felt artificial, default mergeResults in toolchest implementation for topn, search, select
* adjust javadoc
* adjustments
* oops
* use it
* use BinaryOperator, remove CombiningFunction, use Comparator instead of Ordering, other review adjustments
* rename createComparator to createResultComparator, fix typo, firstNonNull nullable parameters
* disable all compression in intermediate segment persists while ingestion
* more changes and build fix
* by default retain existing indexingSpec for intermediate persisted segments
* document indexSpecForIntermediatePersists index tuning config
* fix build issues
* update serde tests
Make static imports forbidden in tests and remove all occurrences to be
consistent with the non-test code.
Also, various changes to files affected by above:
- Reformat to adhere to druid style guide
- Fix various IntelliJ warnings
- Fix various SonarLint warnings (e.g., the expected/actual args to
Assert.assertEquals() were flipped)
* Add state and error tracking for seekable stream supervisors
* Fixed nits in docs
* Made inner class static and updated spec test with jackson inject
* Review changes
* Remove redundant config param in supervisor
* Style
* Applied some of Jon's recommendations
* Add transience field
* write test
* implement code review changes except for reconsidering logic of markRunFinishedAndEvaluateHealth()
* remove transience reporting and fix SeekableStreamSupervisorStateManager impl
* move call to stateManager.markRunFinished() from RunNotice to runInternal() for tests
* remove stateHistory because it wasn't adding much value, some fixes, and add more tests
* fix tests
* code review changes and add HTTP health check status
* fix test failure
* refactor to split into a generic SupervisorStateManager and a specific SeekableStreamSupervisorStateManager
* fixup after merge
* code review changes - add additional docs
* cleanup KafkaIndexTaskTest
* add additional documentation for Kinesis indexing
* remove unused throws class
ambari depends on hadoop-annotation. Under linux, it sometimes activates a
maven profile that includes an explicit dependency on ${java.home}/../lib/tools.jar
This change excludes this dependency, since this jar is no longer
included with Java 9. It also seems seems unlikely that we would require
this dependency at runtime, since it is only enabled on some platforms.
* Add checkstyle for "Local variable names shouldn't start with capital"
* Adjust some local variables to constants
* Replace StringUtils.LINE_SEPARATOR with System.lineSeparator()
* Upgrade various build and doc links to https.
Where it wasn't possible to upgrade build-time dependencies to https,
I kept http in place but used hardcoded checksums or GPG keys to ensure
that artifacts fetched over http are verified properly.
* Switch to https://apache.org.