/
exec.go
172 lines (149 loc) · 3.86 KB
/
exec.go
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// Copyright 2019 CUE 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 exec
//go:generate go run gen.go
//go:generate gofmt -s -w .
import (
"fmt"
"os/exec"
"strings"
"cuelang.org/go/cue"
"cuelang.org/go/cue/errors"
"cuelang.org/go/internal/task"
)
func init() {
task.Register("tool/exec.Run", newExecCmd)
// For backwards compatibility.
task.Register("exec", newExecCmd)
}
type execCmd struct{}
func newExecCmd(v cue.Value) (task.Runner, error) {
return &execCmd{}, nil
}
func (c *execCmd) Run(ctx *task.Context) (res interface{}, err error) {
cmd, doc, err := mkCommand(ctx)
if err != nil {
return cue.Value{}, err
}
// TODO: set environment variables, if defined.
stream := func(name string) (stream cue.Value, ok bool) {
c := ctx.Obj.Lookup(name)
// Although the schema defines a default versions, older implementations
// may not use it yet.
if !c.Exists() {
return
}
if err := c.Null(); ctx.Err != nil || err == nil {
return
}
return c, true
}
if v, ok := stream("stdin"); !ok {
cmd.Stdin = ctx.Stdin
} else if cmd.Stdin, err = v.Reader(); err != nil {
return nil, errors.Wrapf(err, v.Pos(), "invalid input")
}
_, captureOut := stream("stdout")
if !captureOut {
cmd.Stdout = ctx.Stdout
}
_, captureErr := stream("stderr")
if !captureErr {
cmd.Stderr = ctx.Stderr
}
update := map[string]interface{}{}
if captureOut {
var stdout []byte
stdout, err = cmd.Output()
update["stdout"] = string(stdout)
} else {
err = cmd.Run()
}
update["success"] = err == nil
if err != nil {
if exit := (*exec.ExitError)(nil); errors.As(err, &exit) && captureErr {
update["stderr"] = string(exit.Stderr)
} else {
update = nil
}
err = fmt.Errorf("command %q failed: %v", doc, err)
}
return update, err
}
func mkCommand(ctx *task.Context) (c *exec.Cmd, doc string, err error) {
var bin string
var args []string
v := ctx.Lookup("cmd")
if ctx.Err != nil {
return nil, "", ctx.Err
}
switch v.Kind() {
case cue.StringKind:
str := ctx.String("cmd")
doc = str
list := strings.Fields(str)
bin = list[0]
args = append(args, list[1:]...)
case cue.ListKind:
list, _ := v.List()
if !list.Next() {
return nil, "", errors.New("empty command list")
}
bin, err = list.Value().String()
if err != nil {
return nil, "", err
}
doc += bin
for list.Next() {
str, err := list.Value().String()
if err != nil {
return nil, "", err
}
args = append(args, str)
doc += " " + str
}
}
if bin == "" {
return nil, "", errors.New("empty command")
}
cmd := exec.CommandContext(ctx.Context, bin, args...)
cmd.Dir, _ = ctx.Obj.Lookup("dir").String()
env := ctx.Obj.Lookup("env")
// List case.
for iter, _ := env.List(); iter.Next(); {
str, err := iter.Value().String()
if err != nil {
return nil, "", errors.Wrapf(err, v.Pos(),
"invalid environment variable value %q", v)
}
cmd.Env = append(cmd.Env, str)
}
// Struct case.
for iter, _ := ctx.Obj.Lookup("env").Fields(); iter.Next(); {
label := iter.Label()
v := iter.Value()
var str string
switch v.Kind() {
case cue.StringKind:
str, _ = v.String()
case cue.IntKind, cue.FloatKind, cue.NumberKind:
str = fmt.Sprint(v)
default:
return nil, "", errors.Newf(v.Pos(),
"invalid environment variable value %q", v)
}
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", label, str))
}
return cmd, doc, nil
}