[PROPOSAL] Switch from gometalinter to golangci-lint

[bflad]

Our TravisCI implementation with gometalinter has been a successful experiment in utilizing the various Go community linting tools to help improve the codebase quality and prevent common pull request review items. Recently though, we have consistently been having performance and functionality issues, especially after the switch from govendor to Go modules. Errantly failing TravisCI runs due to the linting timeouts distracts from useful review and feedback. Certain linting issues also appear to be missing occassionally from the output.

The choice of gometalinter at the time of the initial implementation was based purely on gometalinter having a well established base and golangci-lint being new to the scene. Since then, golangci-lint has grown in usage and appears to reflect Go language/tooling updates in a timely manner. It seems to work out of the box with our Go modules setup outside the GOPATH.

While the Terraform AWS Provider and the Terraform Azure* Providers have been leading the experimentation with Go linting among actively maintained HashiCorp Terraform Providers, there are no currently defined Terraform provider development standards for code quality based on specific tooling. Given this, we should feel free to swap the implementation either temporarily to workaround the current issues or more permanently should it make sense.

By example, here is the performance improvement for me locally when working outside the GOPATH (2.8 GHz Intel Core i7):

# gometalinter
$ time make lint
==> Checking source code against linters...
make lint  412.87s user 371.90s system 476% cpu 2:44.75 total

# golangci-lint
$ time make lint
==> Checking source code against linters...
make lint  74.04s user 7.21s system 355% cpu 22.842 total

The previous commits in this pull request fix new linting issues found from the updated linters in golangci-lint. They can be cherry-picked into the codebase outside the lint tooling changes as necessary.

$ make lint
==> Checking source code against linters...
aws/resource_aws_iam_user_test.go:639:85: unnecessary conversion (unconvert)
    authenticationCode1, err := totp.GenerateCode(secret, time.Now().Add(time.Duration(-30*time.Second)))
                                                                                      ^
aws/config_test.go:49:15: Error return value of `buf.ReadFrom` is not checked (errcheck)
    buf.ReadFrom(r.Body)
                ^
aws/resource_aws_budgets_budget_test.go:331:11: Error return value of `t.Execute` is not checked (errcheck)
  t.Execute(&doc, budgetConfig)
           ^
aws/resource_aws_budgets_budget_test.go:351:11: Error return value of `t.Execute` is not checked (errcheck)
  t.Execute(&doc, budgetConfig)
           ^
aws/resource_aws_budgets_budget_test.go:377:11: Error return value of `t.Execute` is not checked (errcheck)
  t.Execute(&doc, budgetConfig)
           ^
aws/resource_aws_budgets_budget_test.go:397:11: Error return value of `t.Execute` is not checked (errcheck)
  t.Execute(&doc, budgetConfig)
           ^
aws/resource_aws_budgets_budget_test.go:423:11: Error return value of `t.Execute` is not checked (errcheck)
  t.Execute(&doc, budgetConfig)
           ^
aws/resource_aws_ecs_task_definition_test.go:438:32: Error return value of `conn.DeregisterTaskDefinition` is not checked (errcheck)
    conn.DeregisterTaskDefinition(&ecs.DeregisterTaskDefinitionInput{
                                 ^
aws/resource_aws_iam_access_key.go:172:9: Error return value of `h.Write` is not checked (errcheck)
  h.Write(message)
         ^
aws/resource_aws_lambda_function_test.go:472:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func_modified.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:917:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:929:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func_modified.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:973:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:985:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func_modified.js": "lambda.js"}, updatedZipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:1023:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:1036:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func_modified.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:1075:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:1088:31: Error return value of `testAccCreateZipFromFiles` is not checked (errcheck)
          testAccCreateZipFromFiles(map[string]string{"test-fixtures/lambda_func_modified.js": "lambda.js"}, zipFile)
                                   ^
aws/resource_aws_lambda_function_test.go:1488:18: Error return value of `zipFile.Truncate` is not checked (errcheck)
  zipFile.Truncate(0)
                  ^
aws/resource_aws_lambda_function_test.go:1489:14: Error return value of `zipFile.Seek` is not checked (errcheck)
  zipFile.Seek(0, 0)
              ^
aws/resource_aws_s3_bucket_test.go:2085:11: Error return value of `t.Execute` is not checked (errcheck)
  t.Execute(&doc, struct{ GUID int }{GUID: randInt})
           ^
aws/resource_aws_autoscaling_group.go:515:49: `Identifer` is a misspelling of `Identifier` (misspell)
  // Availability Zones are optional if VPC Zone Identifer(s) are specified
                                                 ^
aws/resource_aws_route53_record.go:265:10: `resouce` is a misspelling of `resource` (misspell)
    // for resouce update here we simply fall through to
           ^
aws/resource_aws_db_instance_test.go:1289:56: `identifer` is a misspelling of `identifier` (misspell)
// This acceptance test explicitly tests when snapshot_identifer is set,
                                                       ^
aws/resource_aws_rds_cluster_test.go:1263:56: `identifer` is a misspelling of `identifier` (misspell)
// This acceptance test explicitly tests when snapshot_identifer is set,
                                                       ^
make: *** [lint] Error 1

[bflad]

I'm going to re-run all the failed TravisCI jobs I can find.

[github-actions]

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