Merge branch 'master' into linasn/query-handlers-refactoring

* master: (28 commits)
  [dbnode] Add claims for index segments volume index (#2846)
  [dbnode] Remove namespaces from example config and integration tests (#2866)
  [dbnode] Resurrect flaky test skip (#2868)
  [aggregator] Fix checkCampaignStateLoop (#2867)
  [dbnode] implement deletion method in namespace kvadmin service (#2861)
  Replace closer with resource package (#2864)
  Add coding style guide (#2831)
  Add GOVERNANCE.md to describe governance (#2830)
  Add COMPATIBILITY.md to describe version compatibility (#2829)
  Refactor etcd config as discovery section with convenience types (#2843)
  Refactor x/lockfile into dbnode/server (#2862)
  [lint] Disable nlreturn linter (#2865)
  [m3cluster] Expose placement algorithm in placement service (#2858)
  [etcd] Set reasonable cluster connection/sync settings by default (#2860)
  [dbnode] Use bits.LeadingZeros64 to improve encoder performance (#2857)
  Cleanup m3nsch leftovers (#2856)
  Update ci-scripts to correct coverage tracking (#2854)
  [aggregator] Process campaign state without waiting for first campaign check interval (#2855)
  Bump go to 1.14 (#2853)
  [query] Remove single series error from M3
  ...

.buildkite/hooks/pre-exit

@@ -3,5 +3,7 @@
 set -eo pipefail
 
 echo "--- :git: cleaning checkout"
-chmod -R +w ./_tools || true
+if [[ -d "./_tools" ]]; then
+  chmod -R +w ./_tools
+fi
 git clean -dffx

.buildkite/pipeline.yml

@@ -14,7 +14,7 @@ steps:
     command: make clean install-vendor-m3 test-all-gen
     env:
       CGO_ENABLED: 0
-      GIMME_GO_VERSION: 1.13.x
+      GIMME_GO_VERSION: 1.14.x
     plugins:
         gopath-checkout#v1.0.1:
           import: github.com/m3db/m3
@@ -35,8 +35,17 @@ steps:
         run: app
         workdir: /go/src/github.com/m3db/m3
     <<: *common
-  - name: "Services, Tools, Metalint"
-    command: make clean install-vendor-m3 services tools metalint
+  - name: "Services, Tools"
+    command: make clean install-vendor-m3 services tools
+    plugins:
+      docker-compose#v2.5.1:
+        run: app
+        workdir: /go/src/github.com/m3db/m3
+    <<: *common
+  - name: "Lint"
+    command: make clean lint
+    env:
+      CGO_ENABLED: 0
     plugins:
       docker-compose#v2.5.1:
         run: app
@@ -47,7 +56,7 @@ steps:
     parallelism: 2
     env:
       CGO_ENABLED: 0
-      GIMME_GO_VERSION: 1.13.x
+      GIMME_GO_VERSION: 1.14.x
     plugins:
         gopath-checkout#v1.0.1:
           import: github.com/m3db/m3
@@ -57,7 +66,7 @@ steps:
     parallelism: 1
     env:
       CGO_ENABLED: 0
-      GIMME_GO_VERSION: 1.13.x
+      GIMME_GO_VERSION: 1.14.x
     plugins:
         gopath-checkout#v1.0.1:
           import: github.com/m3db/m3
@@ -90,7 +99,7 @@ steps:
     command: make clean install-vendor-m3 docs-test
     env:
       CGO_ENABLED: 0
-      GIMME_GO_VERSION: 1.13.x
+      GIMME_GO_VERSION: 1.14.x
     plugins:
         gopath-checkout#v1.0.1:
           import: github.com/m3db/m3

.golangci.yml

@@ -0,0 +1,290 @@
+# options for analysis running
+run:
+  # default concurrency is a available CPU number
+  # concurrency: 4
+
+  # timeout for analysis, e.g. 30s, 5m, default is 1m
+  deadline: 10m
+
+  # exit code when at least one issue was found, default is 1
+  issues-exit-code: 1
+
+  # include test files or not, default is true
+  tests: true
+
+  # list of build tags, all linters use it. Default is empty list.
+  build-tags: []
+
+  # which dirs to skip: they won't be analyzed;
+  # can use regexp here: generated.*, regexp is applied on full path;
+  # default value is empty list, but next dirs are always skipped independently
+  # from this option's value:
+  #   	vendor$, third_party$, testdata$, examples$, Godeps$, builtin$
+  skip-dirs:
+    - generated/.*
+    # There is some very weird golangci-lint bug that causes analysis to fail on the
+    # eventlog_server_test.go file (perhaps caused by https://github.com/golangci/golangci-lint/issues/995).
+    # To avoid sporadic CI failures we exclude the file from analysis for the time being.
+    # In order to exclude the file from analysis, and not just any lints in it, we need
+    # to put the file in a separate directory since although golangci-lint skips issues
+    # from files in the skip-files list, it still runs analysis on them.
+    - eventlog/test$
+
+  # which files to skip: they will be analyzed, but issues from them
+  # won't be reported. Default value is empty list, but there is
+  # no need to include all autogenerated files, we confidently recognize
+  # autogenerated files. If it's not please let us know.
+  skip-files: []
+
+  # by default isn't set. If set we pass it to "go list -mod={option}". From "go help modules":
+  # If invoked with -mod=readonly, the go command is disallowed from the implicit
+  # automatic updating of go.mod described above. Instead, it fails when any changes
+  # to go.mod are needed. This setting is most useful to check that go.mod does
+  # not need updates, such as in a continuous integration and testing system.
+  # If invoked with -mod=vendor, the go command assumes that the vendor
+  # directory holds the correct copies of dependencies and ignores
+  # the dependency descriptions in go.mod.
+  # modules-download-mode: readonly|release|vendor
+  modules-download-mode: readonly
+
+
+# output configuration options
+output:
+  # colored-line-number|line-number|json|tab|checkstyle|code-climate, default is "colored-line-number"
+  format: colored-line-number
+
+  # print lines of code with issue, default is true
+  print-issued-lines: true
+
+  # print linter name in the end of issue text, default is true
+  print-linter-name: true
+
+
+# all available settings of specific linters
+linters-settings:
+  govet:
+    # report about shadowed variables
+    check-shadowing: true
+  goimports:
+    # put imports beginning with prefix after 3rd-party packages;
+    # it's a comma-separated list of prefixes
+    local-prefixes: github.com/m3db/m3
+  gocyclo:
+    # minimal code complexity to report, 30 by default (but we recommend 10-20)
+    min-complexity: 10
+  maligned:
+    # print struct with more effective memory layout or not, false by default
+    suggest-new: true
+  dupl:
+    # tokens count to trigger issue, 150 by default
+    threshold: 100
+  goconst:
+    # minimal length of string constant, 3 by default
+    min-len: 3
+    # minimal occurrences count to trigger, 3 by default
+    min-occurrences: 3
+  depguard:
+    list-type: blacklist
+    include-go-root: false
+    packages:
+      - github.com/sirupsen/logrus
+      - github.com/golang/protobuf/jsonpb
+      - google.golang.org/protobuf/encoding/protojson
+      - github.com/golang/protobuf/proto
+      - google.golang.org/protobuf/proto
+      - github.com/tj/assert
+    packages-with-error-messages:
+      # specify an error message to output when a blacklisted package is used
+      github.com/sirupsen/logrus: "logging is allowed only by logutils.Log"
+      github.com/golang/protobuf/jsonpb: "replace with github.com/gogo/protobuf/jsonpb"
+      google.golang.org/protobuf/encoding/protojson: "replace with github.com/gogo/protobuf/jsonpb"
+      github.com/golang/protobuf/proto: "replace with github.com/gogo/protobuf/proto"
+      google.golang.org/protobuf/proto: "replace with github.com/gogo/protobuf/proto"
+      github.com/tj/assert: "use github.com/stretchr/testify/assert"
+  misspell:
+    # Correct spellings using locale preferences for US or UK.
+    # Default is to use a neutral variety of English.
+    # Setting locale to US will correct the British spelling of 'colour' to 'color'.
+    locale: US
+    ignore-words:
+      - someword
+  lll:
+    # max line length, lines longer will be reported. Default is 120.
+    # '\t' is counted as 1 character by default, and can be changed with the tab-width option
+    line-length: 100
+    # tab width in spaces. Default to 1.
+    tab-width: 1
+  unused:
+    # treat code as a program (not a library) and report unused exported identifiers; default is false.
+    # XXX: if you enable this setting, unused will report a lot of false-positives in text editors:
+    # if it's called for subdir of a project it can't find funcs usages. All text editor integrations
+    # with golangci-lint call it on a directory with the changed file.
+    check-exported: false
+  unparam:
+    # Inspect exported functions, default is false. Set to true if no external program/library imports your code.
+    # XXX: if you enable this setting, unparam will report a lot of false-positives in text editors:
+    # if it's called for subdir of a project it can't find external interfaces. All text editor integrations
+    # with golangci-lint call it on a directory with the changed file.
+    check-exported: false
+  nakedret:
+    # make an issue if func has more lines of code than this setting and it has naked returns; default is 30
+    max-func-lines: 30
+  prealloc:
+    # XXX: we don't recommend using this linter before doing performance profiling.
+    # For most programs usage of prealloc will be a premature optimization.
+
+    # Report preallocation suggestions only on simple loops that have no returns/breaks/continues/gotos in them.
+    # True by default.
+    simple: true
+    range-loops: true # Report preallocation suggestions on range loops, true by default
+    for-loops: false # Report preallocation suggestions on for loops, false by default
+  gocritic:
+    # Which checks should be enabled; can't be combined with 'disabled-checks';
+    # See https://go-critic.github.io/overview#checks-overview
+    # To check which checks are enabled run `GL_DEBUG=gocritic golangci-lint run`
+    # By default list of stable checks is used.
+
+    # Enable multiple checks by tags, run `GL_DEBUG=gocritic golangci-lint` run to see all tags and checks.
+    # Empty list by default. See https://github.com/go-critic/go-critic#usage -> section "Tags".
+    enabled-tags:
+      - performance
+    enabled-checks:
+      - ruleguard
+    settings: # settings passed to gocritic
+      captLocal: # must be valid enabled check name
+        paramsOnly: true
+      rangeValCopy:
+        sizeThreshold: 32
+      ruleguard:
+        rules: "src/cmd/tools/linter/gorules/rules.go"
+  gci:
+    # gci control golang package import order and make it always deterministic
+    local-prefixes: github.com/m3db/m3
+
+linters:
+  enable:
+    - deadcode
+    - dogsled
+    - dupl
+    - errcheck
+    - exhaustive
+    - gci
+    - goconst
+    - gocritic
+    - gocyclo
+    - godox
+    - goimports
+    - golint
+    - gosimple
+    - govet
+    - ineffassign
+    - lll
+    - maligned
+    - megacheck
+    - misspell
+    - prealloc
+    - staticcheck
+    - structcheck
+    - typecheck
+    - unconvert
+    - unparam
+    - varcheck
+  enable-all: false
+  disable:
+    - gomnd
+    - gochecknoinits
+    # Globals gonna global
+    - gochecknoglobals
+    # Overly harsh about long functions
+    - funlen
+    # Linter that checks that every comment ends in a period.
+    - godot
+    # Linter that makes you always use _test packages.
+    - testpackage
+    # Overly opinionated about how to construct errors
+    - goerr113
+    # Noisy warnings about whether "nolint" directives are necessary
+    - nolintlint
+    # Deprecated project due to being prone to bad suggestions.
+    - interfacer
+    # Valid use for not explicitly setting every field when they are optional nil/empty.
+    - exhaustivestruct
+    # We allow cuddling assignment following conditions because there are valid 
+    # logical groupings for this use-case (e.g. when evaluating config values).
+    - wsl
+    # New line required before return would require a large fraction of the
+    # code base to need updating, it's not worth the perceived benefit.
+    - nlreturn
+  disable-all: false
+  presets:
+    # bodyclose, errcheck, gosec, govet, scopelint, staticcheck, typecheck
+    - bugs
+    # deadcode, ineffassign, structcheck, unparam, unused, varcheck
+    - unused
+    # gofmt, goimports
+    - format
+    # depguard, dupl, gochecknoglobals, gochecknoinits, goconst, gocritic,
+    # golint, gosimple, interfacer, lll, misspell, stylecheck, unconvert
+    - style
+  fast: false
+
+
+issues:
+  # List of regexps of issue texts to exclude, empty list by default.
+  # But independently from this option we use default exclude patterns,
+  # it can be disabled by `exclude-use-default: false`. To list all
+  # excluded by default patterns execute `golangci-lint run --help`
+  exclude:
+    # Exclude table-driven tests from scopelint (https://github.com/golangci/golangci-lint/issues/281).
+    - "Using the variable on range scope `tt` in function literal"
+    - "Using the variable on range scope `test` in function literal"
+    # It's common to shadow `err` and rarely indicates a problems. See
+    # https://github.com/golang/go/issues/19490 for further details.
+    - 'shadow: declaration of "err" shadows declaration'
+    # We commonly expose profiling information on /debug/pprof so we need to disable the gosec
+    # lint for it.
+    - "Profiling endpoint is automatically exposed on /debug/pprof"
+    # We only use md5 for non-cryptographic purposes (e.g. generating ID's where we don't assume
+    # the ID's are cryptographicly secure).
+    - "Blacklisted import `crypto/md5`: weak cryptographic primitive"
+    # The logger is often our last option to communicate that an error occurred so if it returns
+    # an error we don't have an alternative to use. Since it's already unlikely that `Log` will
+    # return an error anyway we often skip checking the error for brevity.
+    - "Error return value of `\\(github.com\\/go-kit\\/kit\\/log.Logger\\).Log` is not checked"
+    # The caller is responsible for closing the Body of an `http.Response`. However, this step
+    # is usually performed in a defer function after the response has already been processed and
+    # so errors, which are already rare, can usually be safely ignored.
+    - "Error return value of `[a-zA-Z.]+.Body.Close` is not checked"
+    # The errcheck linter already checks for unhandled errors so we can disable the equivalent
+    # lint by gosec.
+    - "G104: Errors unhandled"
+
+  # Excluding configuration per-path, per-linter, per-text and per-source
+  exclude-rules:
+    # Exclude lll issues for long lines with go:generate
+    - linters:
+        - lll
+      source: "^//go:generate "
+    # Exclude some linters from running on tests files.
+    # - path: _test\.go
+    #   linters:
+    #     - gocyclo
+    #     - errcheck
+    #     - dupl
+    #     - gosec
+
+
+  # Independently from option `exclude` we use default exclude patterns,
+  # it can be disabled by this option. To list all
+  # excluded by default patterns execute `golangci-lint run --help`.
+  # Default value for this option is true.
+  exclude-use-default: false
+
+  # Maximum issues count per one linter. Set to 0 to disable. Default is 50.
+  max-issues-per-linter: 0
+
+  # Maximum count of issues with the same text. Set to 0 to disable. Default is 3.
+  max-same-issues: 0
+
+  # Show only new issues created after git revision `REV`
+  new-from-rev: 5a3a12bba59e058b7a4cee6ec472c3f5786f741b