cleanup some dead kubectl code and narrow scope of helpers

pkg/kubectl/cmd/set/env/env_parse.go

@@ -0,0 +1,137 @@
+/*
+Copyright 2017 The Kubernetes 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 env
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
+)
+
+var argumentEnvironment = regexp.MustCompile("(?ms)^(.+)\\=(.*)$")
+var validArgumentEnvironment = regexp.MustCompile("(?ms)^(\\w+)\\=(.*)$")
+
+// IsEnvironmentArgument checks whether a string is an environment argument, that is, whether it matches the "anycharacters=anycharacters" pattern.
+func IsEnvironmentArgument(s string) bool {
+	return argumentEnvironment.MatchString(s)
+}
+
+// IsValidEnvironmentArgument checks whether a string is a valid environment argument, that is, whether it matches the "wordcharacters=anycharacters" pattern. Word characters can be letters, numbers, and underscores.
+func IsValidEnvironmentArgument(s string) bool {
+	return validArgumentEnvironment.MatchString(s)
+}
+
+// SplitEnvironmentFromResources separates resources from environment arguments.
+// Resources must come first. Arguments may have the "DASH-" syntax.
+func SplitEnvironmentFromResources(args []string) (resources, envArgs []string, ok bool) {
+	first := true
+	for _, s := range args {
+		// this method also has to understand env removal syntax, i.e. KEY-
+		isEnv := IsEnvironmentArgument(s) || strings.HasSuffix(s, "-")
+		switch {
+		case first && isEnv:
+			first = false
+			fallthrough
+		case !first && isEnv:
+			envArgs = append(envArgs, s)
+		case first && !isEnv:
+			resources = append(resources, s)
+		case !first && !isEnv:
+			return nil, nil, false
+		}
+	}
+	return resources, envArgs, true
+}
+
+// parseIntoEnvVar parses the list of key-value pairs into kubernetes EnvVar.
+// envVarType is for making errors more specific to user intentions.
+func parseIntoEnvVar(spec []string, defaultReader io.Reader, envVarType string) ([]v1.EnvVar, []string, error) {
+	env := []v1.EnvVar{}
+	exists := sets.NewString()
+	var remove []string
+	for _, envSpec := range spec {
+		switch {
+		case !IsValidEnvironmentArgument(envSpec) && !strings.HasSuffix(envSpec, "-"):
+			return nil, nil, fmt.Errorf("%ss must be of the form key=value and can only contain letters, numbers, and underscores", envVarType)
+		case envSpec == "-":
+			if defaultReader == nil {
+				return nil, nil, fmt.Errorf("when '-' is used, STDIN must be open")
+			}
+			fileEnv, err := readEnv(defaultReader, envVarType)
+			if err != nil {
+				return nil, nil, err
+			}
+			env = append(env, fileEnv...)
+		case strings.Index(envSpec, "=") != -1:
+			parts := strings.SplitN(envSpec, "=", 2)
+			if len(parts) != 2 {
+				return nil, nil, fmt.Errorf("invalid %s: %v", envVarType, envSpec)
+			}
+			exists.Insert(parts[0])
+			env = append(env, v1.EnvVar{
+				Name:  parts[0],
+				Value: parts[1],
+			})
+		case strings.HasSuffix(envSpec, "-"):
+			remove = append(remove, envSpec[:len(envSpec)-1])
+		default:
+			return nil, nil, fmt.Errorf("unknown %s: %v", envVarType, envSpec)
+		}
+	}
+	for _, removeLabel := range remove {
+		if _, found := exists[removeLabel]; found {
+			return nil, nil, fmt.Errorf("can not both modify and remove the same %s in the same command", envVarType)
+		}
+	}
+	return env, remove, nil
+}
+
+// ParseEnv parses the elements of the first argument looking for environment variables in key=value form and, if one of those values is "-", it also scans the reader.
+// The same environment variable cannot be both modified and removed in the same command.
+func ParseEnv(spec []string, defaultReader io.Reader) ([]v1.EnvVar, []string, error) {
+	return parseIntoEnvVar(spec, defaultReader, "environment variable")
+}
+
+func readEnv(r io.Reader, envVarType string) ([]v1.EnvVar, error) {
+	env := []v1.EnvVar{}
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		envSpec := scanner.Text()
+		if pos := strings.Index(envSpec, "#"); pos != -1 {
+			envSpec = envSpec[:pos]
+		}
+		if strings.Index(envSpec, "=") != -1 {
+			parts := strings.SplitN(envSpec, "=", 2)
+			if len(parts) != 2 {
+				return nil, fmt.Errorf("invalid %s: %v", envVarType, envSpec)
+			}
+			env = append(env, v1.EnvVar{
+				Name:  parts[0],
+				Value: parts[1],
+			})
+		}
+	}
+	if err := scanner.Err(); err != nil && err != io.EOF {
+		return nil, err
+	}
+	return env, nil
+}