Provide Is functionality (#5)

.github/workflows/ci.yaml

@@ -0,0 +1,63 @@
+# Copyright 2019 Iguazio
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+name: CI
+
+on: [ push, pull_request ]
+
+jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-go@v3
+        with:
+          go-version: "1.17"
+
+      - uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cache/go-build
+            ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go-
+
+      - name: Lint
+        run: make lint
+
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-go@v3
+        with:
+          go-version: "1.17"
+
+      - uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cache/go-build
+            ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go-
+
+      - name: Test
+        run: make test

.gitignore

@@ -0,0 +1 @@
+.idea/

Makefile

@@ -0,0 +1,61 @@
+# Copyright 2019 Iguazio
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+GOPATH ?= $(shell go env GOPATH)
+OS_NAME = $(shell uname)
+
+ensure-gopath:
+ifndef GOPATH
+	$(error GOPATH must be set)
+endif
+
+.PHONY: modules
+modules: ensure-gopath
+	@echo Getting go modules
+	@go mod download
+
+.PHONY: fmt
+fmt:
+	gofmt -s -w .
+
+.PHONY: lint
+lint: modules
+	@echo Installing linters...
+	@test -e $(GOPATH)/bin/impi || \
+		(mkdir -p $(GOPATH)/bin && \
+		curl -s https://api.github.com/repos/pavius/impi/releases/latest \
+		| grep -i "browser_download_url.*impi.*$(OS_NAME)" \
+		| cut -d : -f 2,3 \
+		| tr -d \" \
+		| wget -O $(GOPATH)/bin/impi -qi - \
+		&& chmod +x $(GOPATH)/bin/impi)
+
+	@test -e $(GOPATH)/bin/golangci-lint || \
+	  	(curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(GOPATH)/bin v1.41.1)
+
+	@echo Verifying imports...
+	$(GOPATH)/bin/impi \
+		--local github.com/nuclio/errors/ \
+		--scheme stdLocalThirdParty \
+		./...
+
+	@echo Linting...
+	$(GOPATH)/bin/golangci-lint run -v
+	@echo Done.
+
+.PHONY: test
+test: modules
+	go test -v ./... -p 1

errors.go

@@ -1,15 +1,19 @@
 /*
 Copyright 2019 The Nuclio Authors.
+
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
+
     http://www.apache.org/licenses/LICENSE-2.0
+
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
 // Package errors provides an api similar to github.com/nuclio/nuclio/pkg/errors
 // However we don't carry stack trace around for performance
 // (see https://github.com/pkg/errors/issues/124)
@@ -23,6 +27,7 @@ package errors
 
 import (
 	"bytes"
+	buildinterrors "errors"
 	"fmt"
 	"io"
 	"os"
@@ -49,7 +54,7 @@ func init() {
 	ShowLineInfo = len(os.Getenv("NUCLIO_NO_ERROR_LINE_INFO")) == 0
 }
 
-// caller return the caller informatin (file, line)
+// caller return the caller information (file, line)
 // Note this is sensitive to where it's called
 func caller() (string, int) {
 	pcs := make([]uintptr, 1)
@@ -120,6 +125,10 @@ func Wrapf(err error, format string, args ...interface{}) error {
 	return errObj
 }
 
+func Is(base, target error) bool {
+	return buildinterrors.Is(base, target)
+}
+
 // Error is the string representation of the error
 func (err *Error) Error() string {
 	return err.message
@@ -297,7 +306,7 @@ func (err *Error) Format(s fmt.State, verb rune) {
 		}
 		fallthrough
 	case 's':
-		fmt.Fprintf(s, err.Error()) // nolint: errcheck
+		fmt.Fprint(s, err.Error()) // nolint: errcheck
 	case 'q':
 		fmt.Fprintf(s, "%q", err.Error()) // nolint: errcheck
 	}

errors_test.go

@@ -1,19 +1,24 @@
 /*
 Copyright 2019 The Nuclio Authors.
+
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
+
     http://www.apache.org/licenses/LICENSE-2.0
+
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
 package errors
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"path"
@@ -27,6 +32,26 @@ type ErrorsTestSuite struct {
 	suite.Suite
 }
 
+func (suite *ErrorsTestSuite) TestIs() {
+	message := "hello"
+
+	// the fact they have same message, does not mean they are the same error
+	suite.Require().Equal(false, Is(New(message), New(message)))
+
+	// the fact they have same message, does not mean they are the same error, even when wrapped
+	suite.Require().Equal(false, Is(Wrap(New(message), "wrapped"), New(message)))
+
+	// error is indeed a context cancelled
+	suite.Require().Equal(true, Is(context.Canceled, context.Canceled))
+	suite.Require().Equal(true, Is(Wrap(context.Canceled, "wrapped"), context.Canceled))
+
+	// error is indeed someErr
+	someErr := errors.New("some error")
+	suite.Require().Equal(true, Is(someErr, someErr))
+	suite.Require().Equal(true, Is(Wrap(someErr, "wrapped"), someErr))
+	suite.Require().Equal(true, Is(Wrap(Wrap(someErr, "wrapped"), "TopWrapped"), someErr))
+}
+
 func (suite *ErrorsTestSuite) TestNew() {
 	var err error // Make sure we conform to Error interface
 	message := "hello"

go.mod

@@ -1,3 +1,11 @@
 module github.com/nuclio/errors
 
-go 1.12
+go 1.17
+
+require github.com/stretchr/testify v1.8.0
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=