feat: add envmap package

pkg/envmap/doc.go

@@ -0,0 +1,20 @@
+/*
+Copyright The CloudNativePG Contributors
+
+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 envmap is a set of utility functions to manage a process
+// environment as a map between the environment variable names and their
+// value
+package envmap

pkg/envmap/envutils.go

@@ -0,0 +1,91 @@
+/*
+Copyright The CloudNativePG Contributors
+
+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 envmap
+
+import (
+	"fmt"
+	"maps"
+	"os"
+	"strings"
+
+	"github.com/cloudnative-pg/machinery/pkg/stringset"
+)
+
+// ErrWrongEnvironmentString is raised when the Parse function detects
+// a wrong environment string.
+// By convention, the strings in environment should have the form
+// "name=value".
+//
+// See: https://www.man7.org/linux/man-pages/man7/environ.7.html
+type ErrWrongEnvironmentString struct {
+	entry string
+}
+
+// Error implements the error interface.
+func (e *ErrWrongEnvironmentString) Error() string {
+	return fmt.Sprintf("wrong environment variable entry: %s", e.entry)
+}
+
+// EnvironmentMap represent a map between environment variable names
+// and their value.
+type EnvironmentMap map[string]string
+
+// Parse parses a list of strings in the form "foo=bar" into an environment map.
+// If an envalid string is detected, this function will return a
+// ErrWrongEnvironmentString error for the invalid entry.
+func Parse(env []string) (EnvironmentMap, error) {
+	result := make(map[string]string, len(env))
+
+	for _, entry := range env {
+		prefix, suffix, found := strings.Cut(entry, "=")
+		if !found {
+			return nil, &ErrWrongEnvironmentString{
+				entry: entry,
+			}
+		}
+
+		result[prefix] = suffix
+	}
+
+	return result, nil
+}
+
+// StringSlice converts an environment map to a list of strings in the form "foo=bar".
+// The returned list is sorted in lexicographic key order.
+func (e EnvironmentMap) StringSlice() []string {
+	keys := stringset.FromKeys(e).ToSortedList()
+	result := make([]string, len(keys))
+	for i, keyName := range keys {
+		result[i] = fmt.Sprintf("%s=%s", keyName, e[keyName])
+	}
+	return result
+}
+
+// ParseEnviron returns the environment of the current process.
+func ParseEnviron() (EnvironmentMap, error) {
+	return Parse(os.Environ())
+}
+
+// Merge merges two environment maps.
+// When a key in e1 is also present in e2,
+// the value associated with the key in e2 will be used.
+func Merge(e1, e2 EnvironmentMap) EnvironmentMap {
+	result := make(EnvironmentMap, len(e1)+len(e2))
+	maps.Copy(result, e1)
+	maps.Copy(result, e2)
+	return result
+}

pkg/envmap/envutils_test.go

@@ -0,0 +1,185 @@
+/*
+Copyright The CloudNativePG Contributors
+
+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 envmap
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Environment map", func() {
+	DescribeTable(
+		"Environment map parsing",
+		func(env []string, expectedResult EnvironmentMap, expectedError error) {
+			result, err := Parse(env)
+			if expectedError == nil {
+				Expect(err).ToNot(HaveOccurred())
+			} else {
+				Expect(err).To(Equal(expectedError))
+			}
+			Expect(result).To(Equal(expectedResult))
+		},
+		Entry(
+			"nil slice",
+			nil,
+			map[string]string{},
+			nil,
+		),
+		Entry(
+			"basic test",
+			[]string{
+				"PATH=/usr/local/bin:/usr/bin",
+				"TERM=xterm-256color",
+			},
+			map[string]string{
+				"PATH": "/usr/local/bin:/usr/bin",
+				"TERM": "xterm-256color",
+			},
+			nil,
+		),
+		Entry(
+			"duplicate key",
+			[]string{
+				"PATH=/usr/local/bin:/usr/bin",
+				"PATH=/usr/bin",
+			},
+			map[string]string{
+				"PATH": "/usr/bin",
+			},
+			nil,
+		),
+		Entry(
+			"wrong entry (too many equal signs)",
+			[]string{
+				"PATH=/usr/local/bin:/usr/bin",
+				"TERM=xterm-256color=boh",
+			},
+			map[string]string{
+				"PATH": "/usr/local/bin:/usr/bin",
+				"TERM": "xterm-256color=boh",
+			},
+			nil,
+		),
+		Entry(
+			"wrong entry (no equal sign)",
+			[]string{
+				"PATH=/usr/local/bin:/usr/bin",
+				"TERM",
+			},
+			nil,
+			&ErrWrongEnvironmentString{
+				entry: "TERM",
+			},
+		),
+	)
+
+	It("parses the current environment", func() {
+		envMap, err := ParseEnviron()
+		Expect(err).ToNot(HaveOccurred())
+		Expect(envMap).ToNot(BeNil())
+	})
+
+	DescribeTable(
+		"Environment map merging",
+		func(e1, e2, result EnvironmentMap) {
+			Expect(Merge(e1, e2)).To(Equal(result))
+		},
+		Entry(
+			"nil arguments",
+			nil,
+			nil,
+			map[string]string{},
+		),
+		Entry(
+			"e1 is nil",
+			nil,
+			map[string]string{
+				"PATH": "/usr/local/bin",
+			},
+			map[string]string{
+				"PATH": "/usr/local/bin",
+			},
+		),
+		Entry(
+			"e2 is nil",
+			map[string]string{
+				"PATH": "/usr/local/bin",
+			},
+			nil,
+			map[string]string{
+				"PATH": "/usr/local/bin",
+			},
+		),
+		Entry(
+			"e1 and e2 have no common keys",
+			map[string]string{
+				"PATH": "/usr/local/bin",
+			},
+			map[string]string{
+				"TERM": "xterm-256color",
+			},
+			map[string]string{
+				"PATH": "/usr/local/bin",
+				"TERM": "xterm-256color",
+			},
+		),
+		Entry(
+			"e1 and e2 have common keys, e2 will override e1",
+			map[string]string{
+				"PATH": "/usr/local/bin",
+				"TERM": "xterm-256color",
+			},
+			map[string]string{
+				"PATH": "/etc",
+			},
+			map[string]string{
+				"PATH": "/etc",
+				"TERM": "xterm-256color",
+			},
+		),
+	)
+
+	DescribeTable(
+		"Environment map StringSlice",
+		func(e EnvironmentMap, expectedResult []string) {
+			Expect(e.StringSlice()).To(Equal(expectedResult))
+		},
+		Entry(
+			"nil environment map",
+			nil,
+			[]string{},
+		),
+		Entry(
+			"empty environment map",
+			map[string]string{},
+			[]string{},
+		),
+		Entry(
+			"environment map sorted in lexicographical order",
+			map[string]string{
+				"TERM":    "xterm-256color",
+				"PATH":    "/usr/local/bin",
+				"GPG_TTY": "/dev/ttys008",
+			},
+			[]string{
+				"GPG_TTY=/dev/ttys008",
+				"PATH=/usr/local/bin",
+				"TERM=xterm-256color",
+			},
+		),
+	)
+})

pkg/envmap/suite_test.go

@@ -0,0 +1,33 @@
+/*
+Copyright The CloudNativePG Contributors
+
+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 envmap
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+// These tests use Ginkgo (BDD-style Go testing framework). Refer to
+// http://onsi.github.io/ginkgo/ to learn more about Ginkgo.
+
+func TestEnvUtils(t *testing.T) {
+	RegisterFailHandler(Fail)
+
+	RunSpecs(t, "Environment variables utils test")
+}