Integrate CRUD statistics with metrics rock

If `metrics` [1] found, you can use metrics collectors to store
statistics. `metrics >= 0.10.0` is required to use metrics driver.
(`metrics >= 0.9.0` is required to use summary quantiles with
age buckets. `metrics >= 0.5.0, < 0.9.0` is unsupported
due to quantile overflow bug [2]. `metrics == 0.9.0` has bug that do
not permits to create summary collector without quantiles [3].
In fact, user may use `metrics >= 0.5.0`, `metrics != 0.9.0`
if he wants to use metrics without quantiles, and `metrics >= 0.9.0`
if he wants to use metrics with quantiles. But this is confusing,
so let's use a single restriction for both cases.)

The metrics are part of global registry and can be exported together
(e.g. to Prometheus) with default tools without any additional
configuration. Disabling stats destroys the collectors.

Metrics collectors are used by default if supported. To explicitly set
driver, call `crud.enable_stats{ driver = driver }` ('local' or
'metrics'). To enable quantiles, call
`crud.enable_stats{ driver = 'metrics', quantiles = true }`.
With quantiles, `latency` statistics are changed to 0.99 quantile
of request execution time (with aging). Quantiles computations increases
performance overhead by near 10% when used in statistics.

Add CI matrix to run tests with `metrics` installed. To get full
coverage on coveralls, #248 must be resolved.

1. https://github.com/tarantool/metrics
2. tarantool/metrics#235
3. tarantool/metrics#262

Closes #224

.github/workflows/test_on_push.yaml

@@ -13,13 +13,24 @@ jobs:
       matrix:
         # We need 1.10.6 here to check that module works with
         # old Tarantool versions that don't have "tuple-keydef"/"tuple-merger" support.
-        tarantool-version: ["1.10.6", "1.10", "2.2", "2.3", "2.4", "2.5", "2.6", "2.7"]
+        tarantool-version: ["1.10.6", "1.10", "2.2", "2.3", "2.4", "2.5", "2.6", "2.7", "2.8"]
+        metrics-version: [""]
         remove-merger: [false]
+        perf-test: [false]
         include:
+          - tarantool-version: "1.10"
+            metrics-version: "0.12.0"
+            perf-test: true
           - tarantool-version: "2.7"
             remove-merger: true
+          - tarantool-version: "2.8"
+            metrics-version: "0.1.8"
+          - tarantool-version: "2.8"
+            metrics-version: "0.10.0"
           - tarantool-version: "2.8"
             coveralls: true
+            metrics-version: "0.12.0"
+            perf-test: true
       fail-fast: false
     runs-on: [ubuntu-latest]
     steps:
@@ -47,6 +58,10 @@ jobs:
           tarantool --version
           ./deps.sh
 
+      - name: Install metrics
+        if: matrix.metrics-version != ''
+        run: tarantoolctl rocks install metrics ${{ matrix.metrics-version }}
+
       - name: Remove external merger if needed
         if: ${{ matrix.remove-merger }}
         run: rm .rocks/lib/tarantool/tuple/merger.so
@@ -62,6 +77,10 @@ jobs:
       - name: Run tests and code coverage analysis
         run: make -C build coverage
 
+      - name: Run performance tests
+        run: make -C build performance
+        if: ${{ matrix.perf-test }}
+
       - name: Send code coverage to coveralls.io
         run: make -C build coveralls
         if: ${{ matrix.coveralls }}

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added
 * Statistics for CRUD operations on router (#224).
+* Integrate CRUD statistics with [`metrics`](https://github.com/tarantool/metrics) (#224).
 
 ### Changed
 

CMakeLists.txt

@@ -36,6 +36,14 @@ add_custom_target(luatest
   COMMENT "Run regression tests"
 )
 
+set(PERFORMANCE_TESTS_SUBDIR "test/performance")
+
+add_custom_target(performance
+  COMMAND PERF_MODE_ON=true ${LUATEST} -v -c ${PERFORMANCE_TESTS_SUBDIR}
+  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+  COMMENT "Run performance tests"
+)
+
 add_custom_target(coverage
   COMMAND ${LUACOV} ${PROJECT_SOURCE_DIR} && grep -A999 '^Summary' ${CODE_COVERAGE_REPORT}
   DEPENDS ${CODE_COVERAGE_STATS}

README.md

@@ -606,8 +606,24 @@ crud.disable_stats()
 crud.reset_stats()
 ```
 
-Format is as follows.
+If [`metrics`](https://github.com/tarantool/metrics) `0.10.0` or greater
+found, metrics collectors will be used by default to store statistics
+instead of local collectors. You can manually choose driver if needed.
 ```lua
+-- Use metrics collectors. (Default if metrics found).
+crud.enable_stats({ driver = 'metrics' })
+
+-- Use metrics collectors with 0.99 quantile.
+crud.enable_stats({ driver = 'metrics', quantiles = true })
+
+-- Use simple local collectors.
+crud.enable_stats({ driver = 'local' })
+```
+Performance overhead is 3-7% in case of `local` driver and
+5-10% in case of `metrics` driver, up to 20% for `metrics` with quantiles.
+
+Format is as follows.
+```
 crud.stats()
 ---
 - spaces:
@@ -657,9 +673,44 @@ Possible statistics operation labels are
 Each operation section contains of different collectors
 for success calls and error (both error throw and `nil, err`)
 returns. `count` is total requests count since instance start
-or stats restart. `latency` is average time of requests execution,
+or stats restart. `latency` is 0.99 quantile of request execution
+time if `metrics` driver used and quantiles enabled,
+otherwise `latency` is total average.
 `time` is total time of requests execution.
 
+In [`metrics`](https://www.tarantool.io/en/doc/latest/book/monitoring/)
+registry statistics are stored as `tnt_crud_stats` metrics
+with `operation`, `status` and `name` labels. Collector
+`tnt_crud_space_not_found` stores count of calls to unknown spaces,
+`tnt_crud_schema_reloads` stores count of schema reloads in calls.
+```
+metrics:collect()
+---
+- - label_pairs:
+      status: ok
+      operation: insert
+      name: customers
+    value: 221411
+    metric_name: tnt_crud_stats_count
+  - label_pairs:
+      status: ok
+      operation: insert
+      name: customers
+    value: 10.49834896344692
+    metric_name: tnt_crud_stats_sum
+  - label_pairs:
+      status: ok
+      operation: insert
+      name: customers
+      quantile: 0.99
+    value: 0.00023606420935973
+    metric_name: tnt_crud_stats
+  - label_pairs: []
+    value: 3
+    metric_name: tnt_crud_space_not_found
+...
+```
+
 `select` section additionally contains `details` collectors.
 ```lua
 crud.stats('my_space').select.details
@@ -674,9 +725,17 @@ crud.stats('my_space').select.details
 is a count of tuples fetched from storages during execution,
 `tuples_lookup` is a count of tuples looked up on storages
 while collecting response for call.
+In [`metrics`](https://www.tarantool.io/en/doc/latest/book/monitoring/)
+registry they are stored as `tnt_crud_map_reduces`,
+`tnt_crud_tuples_fetched` and `tnt_crud_tuples_lookup` metrics
+with `{ operation = 'select', name = space_name }` labels.
 
 Statistics are preserved between package reloads or [Tarantool Cartridge
 role reloads](https://www.tarantool.io/en/doc/latest/book/cartridge/cartridge_api/modules/cartridge.roles/#reload).
+Beware that metrics 0.12.0 and below do not support
+preserving stats between role reload
+(see [tarantool/metrics#334](https://github.com/tarantool/metrics/issues/334)),
+thus this feature will be unsupported for `metrics` driver.
 
 ## Cartridge roles
 

crud/stats/local_registry.lua

@@ -2,13 +2,16 @@
 -- @module crud.stats.local_registry
 --
 
+local errors = require('errors')
+
 local dev_checks = require('crud.common.dev_checks')
 local op_module = require('crud.stats.operation')
 local registry_common = require('crud.stats.registry_common')
 local stash = require('crud.stats.stash')
 
 local registry = {}
 local internal = stash.get('local_registry')
+local StatsLocalError = errors.new_class('StatsLocalError', {capture_stack = false})
 
 --- Initialize local metrics registry.
 --
@@ -17,9 +20,19 @@ local internal = stash.get('local_registry')
 --
 -- @function init
 --
--- @treturn boolean Returns true.
+-- @tab opts
 --
-function registry.init()
+-- @bool opts.quantiles
+--  Quantiles is not supported for local, only `false` is valid.
+--
+-- @treturn boolean Returns `true`.
+--
+function registry.init(opts)
+    dev_checks({ quantiles = 'boolean' })
+
+    StatsLocalError:assert(opts.quantiles == false,
+        "Quantiles are not supported for 'local' statistics registry")
+
     internal.registry = {}
     internal.registry.spaces = {}
     internal.registry.space_not_found = 0