env.go

Documentation: cuelang.org/go/pkg/tool/os

     1  // Copyright 2019 CUE Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package os
    16  
    17  import (
    18  	"os"
    19  	"strings"
    20  
    21  	"cuelang.org/go/cue"
    22  	"cuelang.org/go/cue/ast"
    23  	"cuelang.org/go/cue/errors"
    24  	"cuelang.org/go/internal/cli"
    25  	"cuelang.org/go/internal/task"
    26  )
    27  
    28  func init() {
    29  	task.Register("tool/os.Getenv", newGetenvCmd)
    30  	task.Register("tool/os.Environ", newEnvironCmd)
    31  
    32  	// TODO:
    33  	// Tasks:
    34  	// - Exit?
    35  	// - Getwd/ Setwd (or in tool/file?)
    36  
    37  	// Functions:
    38  	// - Hostname
    39  	// - UserCache/Home/Config (or in os/user?)
    40  }
    41  
    42  type getenvCmd struct{}
    43  
    44  func newGetenvCmd(v cue.Value) (task.Runner, error) {
    45  	return &getenvCmd{}, nil
    46  }
    47  
    48  func (c *getenvCmd) Run(ctx *task.Context) (res interface{}, err error) {
    49  	iter, err := ctx.Obj.Fields()
    50  	if err != nil {
    51  		return nil, err
    52  	}
    53  
    54  	update := map[string]interface{}{}
    55  
    56  	for iter.Next() {
    57  		name := iter.Label()
    58  		if strings.HasPrefix(name, "$") {
    59  			continue
    60  		}
    61  		v := iter.Value()
    62  
    63  		if err := v.Err(); err != nil {
    64  			return nil, err
    65  		}
    66  
    67  		if err := validateEntry(name, v); err != nil {
    68  			return nil, err
    69  		}
    70  
    71  		str, ok := os.LookupEnv(name)
    72  		if !ok {
    73  			update[name] = nil
    74  			continue
    75  		}
    76  		x, err := fromString(name, str, v)
    77  		if err != nil {
    78  			return nil, err
    79  		}
    80  		update[name] = x
    81  	}
    82  
    83  	return update, nil
    84  }
    85  
    86  type environCmd struct{}
    87  
    88  func newEnvironCmd(v cue.Value) (task.Runner, error) {
    89  	return &environCmd{}, nil
    90  }
    91  
    92  func (c *environCmd) Run(ctx *task.Context) (res interface{}, err error) {
    93  	iter, err := ctx.Obj.Fields()
    94  	if err != nil {
    95  		return nil, err
    96  	}
    97  
    98  	update := map[string]interface{}{}
    99  
   100  	for _, kv := range os.Environ() {
   101  		name, str, _ := strings.Cut(kv, "=")
   102  		if v := ctx.Obj.Lookup(name); v.Exists() {
   103  			update[name], err = fromString(name, str, v)
   104  			if err != nil {
   105  				return nil, err
   106  			}
   107  		} else {
   108  			update[name] = str
   109  		}
   110  	}
   111  
   112  	for iter.Next() {
   113  		name := iter.Label()
   114  		if strings.HasPrefix(name, "$") {
   115  			continue
   116  		}
   117  		v := iter.Value()
   118  		if err := v.Err(); err != nil {
   119  			return nil, err
   120  		}
   121  		if err := validateEntry(name, v); err != nil {
   122  			return nil, err
   123  		}
   124  		if _, ok := update[name]; !ok {
   125  			update[name] = nil
   126  		}
   127  	}
   128  
   129  	return update, nil
   130  }
   131  
   132  func validateEntry(name string, v cue.Value) error {
   133  	if k := v.IncompleteKind(); k&^(cue.NumberKind|cue.NullKind|cue.BoolKind|cue.StringKind) != 0 {
   134  		return errors.Newf(v.Pos(),
   135  			"invalid type %s for environment variable %s", k, name)
   136  	}
   137  	return nil
   138  }
   139  
   140  func fromString(name, str string, v cue.Value) (x ast.Node, err error) {
   141  	k := v.IncompleteKind()
   142  	return cli.ParseValue(v.Pos(), name, str, k)
   143  }
   144
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