fix(linter): fix golangci-lint warnings across substation (#32)

* fix(linter): fix golangci-lint warnings across substation

* handle or explicitly ignore all errors
* remove redundant function calls/conversions
* rename predeclared `caps` identifier
* tools: gofmt -> gofumpt, and staticcheck -> golangci-lint

* fixup! fix(linter): fix golangci-lint warnings across substation

Address code review comments.

Changes include:
- Undoing spurious whitespace changes
- Rename variables with modifiers related to `cap` like newCap
- Adding variable naming conventions to docs

* docs: move first "Environment Variables" heading under "Design"

.github/workflows/code.yml

@@ -21,11 +21,10 @@ jobs:
     - name: tests
       run: go test -timeout 30s -v ./... 
 
-    - name: lint
-      uses: dominikh/staticcheck-action@v1.2.0
+    - name: golangci-lint
+      uses: golangci/golangci-lint-action@v3
       with:
-        install-go: false
-        checks: "all,-ST1000"
+        version: v1.49
 
   python:
     runs-on: ubuntu-latest

.golangci.yml

@@ -0,0 +1,139 @@
+# This code is licensed under the terms of the MIT license.
+
+## Config for golangci-lint v1.49.0 based on https://gist.github.com/maratori/47a4d00457a92aa426dbd48a18776322
+
+run:
+  # Timeout for analysis, e.g. 30s, 5m.
+  # Default: 1m
+  timeout: 3m
+
+
+# This file contains only configs which differ from defaults.
+# All possible options can be found here https://github.com/golangci/golangci-lint/blob/master/.golangci.reference.yml
+linters-settings:
+  cyclop:
+    # The maximal code complexity to report.
+    # Default: 10
+    max-complexity: 30
+
+  errcheck:
+    # Report about not checking of errors in type assertions: `a := b.(MyStruct)`.
+    # Such cases aren't reported by default.
+    # Default: false
+    check-type-assertions: true
+
+  gocognit:
+    # Minimal code complexity to report
+    # Default: 30
+    min-complexity: 45
+
+  # gomodguard:
+  #   blocked:
+  #     # List of blocked modules.
+  #     # Default: []
+  #     modules:
+  #       - github.com/golang/protobuf:
+  #           recommendations:
+  #             - google.golang.org/protobuf
+  #           reason: "see https://developers.google.com/protocol-buffers/docs/reference/go/faq#modules"
+
+  nakedret:
+    # Make an issue if func has more lines of code than this setting, and it has naked returns.
+    # Default: 30
+    max-func-lines: 0
+
+  nolintlint:
+    # Exclude following linters from requiring an explanation.
+    # Default: []
+    allow-no-explanation: [ gocognit ]
+    # Enable to require an explanation of nonzero length after each nolint directive.
+    # Default: false
+    require-explanation: true
+    # Enable to require nolint directives to mention the specific linter being suppressed.
+    # Default: false
+    require-specific: true
+
+  rowserrcheck:
+    # database/sql is always checked
+    # Default: []
+    packages:
+      - github.com/jmoiron/sqlx
+
+  tenv:
+    # The option `all` will run against whole test files (`_test.go`) regardless of method/function signatures.
+    # Otherwise, only methods that take `*testing.T`, `*testing.B`, and `testing.TB` as arguments are checked.
+    # Default: false
+    all: true
+
+
+linters:
+  disable-all: true
+  enable:
+    ## enabled by default
+    - errcheck # checking for unchecked errors, these unchecked errors can be critical bugs in some cases
+    - gosimple # specializes in simplifying a code
+    - govet # reports suspicious constructs, such as Printf calls whose arguments do not align with the format string
+    - ineffassign # detects when assignments to existing variables are not used
+    - staticcheck # is a go vet on steroids, applying a ton of static analysis checks
+    - typecheck # like the front-end of a Go compiler, parses and type-checks Go code
+    - unused # checks for unused constants, variables, functions and types
+
+    ## disabled by default
+    - bidichk # checks for dangerous unicode character sequences
+    - bodyclose # checks whether HTTP response body is closed successfully
+    - cyclop # checks function and package cyclomatic complexity
+    - durationcheck # checks for two durations multiplied together
+    - errname # checks that sentinel errors are prefixed with the Err and error types are suffixed with the Error
+    - execinquery # checks query string in Query function which reads your Go src files and warning it finds
+    - exhaustive # checks exhaustiveness of enum switch statements
+    - gocognit # computes and checks the cognitive complexity of functions
+    - gocyclo # computes and checks the cyclomatic complexity of functions
+    - gomoddirectives # manages the use of 'replace', 'retract', and 'excludes' directives in go.mod
+    - gomodguard # allow and block lists linter for direct Go module dependencies. This is different from depguard where there are different block types for example version constraints and module recommendations
+    - goprintffuncname # checks that printf-like functions are named with f at the end
+    - nakedret # finds naked returns in functions greater than a specified function length
+    - nestif # reports deeply nested if statements
+    - nilerr # finds the code that returns nil even if it checks that the error is not nil
+    - noctx # finds sending http request without context.Context
+    - nolintlint # reports ill-formed or insufficient nolint directives
+    - nosprintfhostport # checks for misuse of Sprintf to construct a host with port in a URL
+    - predeclared # finds code that shadows one of Go's predeclared identifiers
+    - reassign # checks that package variables are not reassigned
+    - rowserrcheck # checks whether Err of rows is checked successfully
+    - sqlclosecheck # checks that sql.Rows and sql.Stmt are closed
+    - tenv # detects using os.Setenv instead of t.Setenv since Go1.17
+    - tparallel # detects inappropriate usage of t.Parallel() method in your Go test codes
+    - unconvert # removes unnecessary type conversions
+    - unparam # reports unused function parameters
+    - usestdlibvars # detects the possibility to use variables/constants from the Go standard library
+    - wastedassign # finds wasted assignment statements
+    - whitespace # detects leading and trailing whitespace
+    - misspell # finds commonly misspelled English words in comments
+
+issues:
+  # Maximum count of issues with the same text.
+  # Set to 0 to disable.
+  # Default: 3
+  max-same-issues: 50
+
+  exclude:
+    - 'declaration of "(err|ctx)" shadows declaration at'
+
+  exclude-rules:
+    - source: "^//\\s*go:generate\\s"
+      linters: [ lll ]
+    - source: "(noinspection|TODO)"
+      linters: [ godot ]
+    - source: "//noinspection"
+      linters: [ gocritic ]
+    - source: "^\\s+if _, ok := err\\.\\([^.]+\\.InternalError\\); ok {"
+      linters: [ errorlint ]
+    - path: "_test\\.go"
+      linters:
+        - bodyclose
+        - dupl
+        - funlen
+        - goconst
+        - gosec
+        - noctx
+        - wrapcheck

.vscode/settings.json

@@ -1,7 +1,12 @@
 {
   "terminal.integrated.defaultProfile.linux": "bash",
-  "go.formatTool": "gofmt",
+  "go.useLanguageServer": true,
+  "gopls": {
+    "formatting.gofumpt": true,
+  },
+  "go.formatTool": "gofumpt",
   "go.inferGopath": false,
-  "go.lintFlags": ["-checks=all,-ST1000"],
   "go.lintOnSave": "workspace",
+  "go.lintTool": "golangci-lint",
+  "cSpell.enabled": false
 }

CONTRIBUTING.md

@@ -54,6 +54,12 @@ We rely on contributors to test changes before they are submitted as pull reques
 
 ### Design Patterns
 
+#### Environment Variables
+
+Substation uses environment variables to customize runtime settings of the system (e.g., concurrency is controlled by `SUBSTATION_CONCURRENCY`). 
+
+Custom applications should implement their own runtime settings as required; for example, the [AWS Lambda application](/cmd/aws/lambda/substation/) uses `SUBSTATION_HANDLER` to manage [invocation settings](https://docs.aws.amazon.com/lambda/latest/dg/lambda-invocation.html).
+
 ##### Configurations
 
 Substation uses a single configuration pattern for all components in the system (see `Config` in [config/config.go](/config/config.go)). This pattern is highly reusable and should be nested to create complex configurations supported by Jsonnet. Below is an example that shows how configurations should be designed:
@@ -86,12 +92,6 @@ Factories are the preferred method for allowing users to customize the system. E
 
 ### Naming Conventions
 
-#### Environment Variables
-
-Substation uses environment variables to customize runtime settings of the system (e.g., concurrency is controlled by `SUBSTATION_CONCURRENCY`). 
-
-Custom applications should implement their own runtime settings as required; for example, the [AWS Lambda application](/cmd/aws/lambda/substation/) uses `SUBSTATION_HANDLER` to manage [invocation settings](https://docs.aws.amazon.com/lambda/latest/dg/lambda-invocation.html).
-
 #### Errors
 
 Errors should always start with `err` (or `Err`, if they are public) and be defined as constants using [internal/errors](/internal/errors/errors.go).
@@ -104,6 +104,10 @@ Environment variable keys and values specific to the Substation application shou
 
 Any environment variable that changes a default runtime setting should always start with SUBSTATION (for example, SUBSTATION_CONCURRENCY).
 
+#### Application Variables
+
+Variable names should always follow conventions from [Effective Go](https://go.dev/doc/effective_go#names), the [Go Code Review Comments](https://github.com/golang/go/wiki/CodeReviewComments#variable-names) and avoid [predeclared identifiers](https://go.dev/ref/spec#Predeclared_identifiers). For example `capsule` is used instead of `cap` to avoid shadowing the capacity function, modifiers and plural usage are `newCapsule`, and `capsules`.
+
 #### Source Metadata
 
 Sources that [add metadata during encapsulation](/config/README.md) should use lowerCamelCase for their JSON keys.

cmd/app.go

@@ -75,8 +75,8 @@ func (sub *Substation) Concurrency() int {
 }
 
 // Send writes encapsulated data into the Transform channel.
-func (sub *Substation) Send(cap config.Capsule) {
-	sub.Channels.Transform.Send(cap)
+func (sub *Substation) Send(capsule config.Capsule) {
+	sub.Channels.Transform.Send(capsule)
 }
 
 /*

cmd/app_test.go

@@ -114,7 +114,10 @@ func TestAppLeaks(t *testing.T) {
 
 	for _, test := range appLeaksTest {
 		sub := New()
-		json.Unmarshal(test.config, &sub.Config)
+		err := json.Unmarshal(test.config, &sub.Config)
+		if err != nil {
+			t.Fatal(err)
+		}
 
 		group, ctx := errgroup.WithContext(context.TODO())
 
@@ -134,15 +137,15 @@ func TestAppLeaks(t *testing.T) {
 
 		// ingest
 		group.Go(func() error {
-			cap := config.NewCapsule()
-			cap.SetData([]byte(`{"foo":"bar"}`))
+			capsule := config.NewCapsule()
+			capsule.SetData([]byte(`{"foo":"bar"}`))
 
 			for w := 0; w < 10; w++ {
 				select {
 				case <-ctx.Done():
 					return ctx.Err()
 				default:
-					sub.Send(cap)
+					sub.Send(capsule)
 				}
 			}
 
@@ -154,6 +157,6 @@ func TestAppLeaks(t *testing.T) {
 
 		// block without checking for errors
 		// this test only checks for leaks
-		sub.Block(ctx, group)
+		_ = sub.Block(ctx, group)
 	}
 }

cmd/aws/lambda/autoscaling/main.go

@@ -19,8 +19,10 @@ const (
 	autoscalePercentage = 50.0
 )
 
-var cloudwatchAPI cloudwatch.API
-var kinesisAPI kinesis.API
+var (
+	cloudwatchAPI cloudwatch.API
+	kinesisAPI    kinesis.API
+)
 
 func init() {
 	cloudwatchAPI.Setup()
@@ -55,7 +57,8 @@ func handler(ctx context.Context, snsEvent events.SNSEvent) error {
 	if err != nil {
 		return fmt.Errorf("handler: %v", err)
 	}
-	log.WithField("alarm", alarmName).WithField("stream", stream).WithField("count", shards).Info("retrieved active shard count")
+	log.WithField("alarm", alarmName).WithField("stream", stream).WithField("count", shards).
+		Info("retrieved active shard count")
 
 	var newShards int64
 	if strings.Contains(alarmName, "upscale") {
@@ -126,10 +129,10 @@ func handler(ctx context.Context, snsEvent events.SNSEvent) error {
 	return nil
 }
 
-func downscale(shards float64, pct float64) int64 {
+func downscale(shards, pct float64) int64 {
 	return int64(math.Ceil(shards - (shards * (pct / 100))))
 }
 
-func upscale(shards float64, pct float64) int64 {
+func upscale(shards, pct float64) int64 {
 	return int64(math.Ceil(shards + (shards * (pct / 100))))
 }