go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/lucictx/exported.go (about)

     1  // Copyright 2016 The LUCI 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 lucictx
    16  
    17  import (
    18  	"io"
    19  	"os"
    20  	"os/exec"
    21  	"strings"
    22  
    23  	"go.chromium.org/luci/common/system/environ"
    24  )
    25  
    26  // Exported represents an exported on-disk LUCI_CONTEXT file.
    27  type Exported interface {
    28  	io.Closer
    29  
    30  	// SetInCmd sets/replaces the LUCI_CONTEXT environment variable in an
    31  	// exec.Cmd.
    32  	SetInCmd(c *exec.Cmd)
    33  
    34  	// SetInEnviron sets/replaces the LUCI_CONTEXT in an environ.Env object.
    35  	SetInEnviron(env environ.Env)
    36  }
    37  
    38  type baseExport struct {
    39  	closed bool
    40  }
    41  
    42  func (e baseExport) assertOpen() {
    43  	if e.closed {
    44  		panic("Using closed lucictx.Exported object")
    45  	}
    46  }
    47  
    48  func (e *baseExport) Close() error {
    49  	e.assertOpen()
    50  	e.closed = true
    51  	return nil
    52  }
    53  
    54  type liveExport struct {
    55  	baseExport
    56  	path   string
    57  	closer func()
    58  }
    59  
    60  func (e *liveExport) SetInCmd(c *exec.Cmd) {
    61  	e.assertOpen()
    62  	pfx := EnvKey + "="
    63  	newVal := pfx + e.path
    64  	if c.Env == nil {
    65  		c.Env = os.Environ()
    66  	}
    67  	for i, l := range c.Env {
    68  		if strings.HasPrefix(strings.ToUpper(l), pfx) {
    69  			c.Env[i] = newVal
    70  			return
    71  		}
    72  	}
    73  	c.Env = append(c.Env, newVal)
    74  }
    75  
    76  func (e *liveExport) SetInEnviron(env environ.Env) {
    77  	e.assertOpen()
    78  	env.Set(EnvKey, e.path)
    79  }
    80  
    81  func (e *liveExport) Close() error {
    82  	e.baseExport.Close()
    83  	e.closer()
    84  	return nil
    85  }
    86  
    87  type nullExport struct {
    88  	baseExport
    89  }
    90  
    91  func (n *nullExport) SetInCmd(c *exec.Cmd) {
    92  	n.assertOpen()
    93  	pfx := EnvKey + "="
    94  	if c.Env == nil {
    95  		c.Env = os.Environ()
    96  	}
    97  	filtered := make([]string, 0, len(c.Env))
    98  	for _, l := range c.Env {
    99  		if !strings.HasPrefix(strings.ToUpper(l), pfx) {
   100  			filtered = append(filtered, l)
   101  		}
   102  	}
   103  	c.Env = filtered
   104  }
   105  
   106  func (n *nullExport) SetInEnviron(env environ.Env) {
   107  	n.assertOpen()
   108  	env.Remove(EnvKey)
   109  }