1// Copyright 2017 Google Inc. All rights reserved.
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
15package build
16
17import (
18	"bufio"
19	"io"
20	"os/exec"
21	"strings"
22	"syscall"
23	"time"
24)
25
26// Cmd is a wrapper of os/exec.Cmd that integrates with the build context for
27// logging, the config's Environment for simpler environment modification, and
28// implements hooks for sandboxing
29type Cmd struct {
30	*exec.Cmd
31
32	Environment *Environment
33	Sandbox     Sandbox
34
35	ctx    Context
36	config Config
37	name   string
38
39	started time.Time
40}
41
42func Command(ctx Context, config Config, name string, executable string, args ...string) *Cmd {
43	ret := &Cmd{
44		Cmd:         exec.CommandContext(ctx.Context, executable, args...),
45		Environment: config.Environment().Copy(),
46		Sandbox:     noSandbox,
47
48		ctx:    ctx,
49		config: config,
50		name:   name,
51	}
52
53	return ret
54}
55
56func (c *Cmd) prepare() {
57	if c.Env == nil {
58		c.Env = c.Environment.Environ()
59	}
60	if c.sandboxSupported() {
61		c.wrapSandbox()
62	}
63
64	c.ctx.Verbosef("%q executing %q %v\n", c.name, c.Path, c.Args)
65	c.started = time.Now()
66}
67
68func (c *Cmd) report() {
69	if state := c.Cmd.ProcessState; state != nil {
70		if c.ctx.Metrics != nil {
71			c.ctx.Metrics.EventTracer.AddProcResInfo(c.name, state)
72		}
73		rusage := state.SysUsage().(*syscall.Rusage)
74		c.ctx.Verbosef("%q finished with exit code %d (%s real, %s user, %s system, %dMB maxrss)",
75			c.name, c.Cmd.ProcessState.ExitCode(),
76			time.Since(c.started).Round(time.Millisecond),
77			c.Cmd.ProcessState.UserTime().Round(time.Millisecond),
78			c.Cmd.ProcessState.SystemTime().Round(time.Millisecond),
79			rusage.Maxrss/1024)
80	}
81}
82
83func (c *Cmd) Start() error {
84	c.prepare()
85	return c.Cmd.Start()
86}
87
88func (c *Cmd) Run() error {
89	c.prepare()
90	err := c.Cmd.Run()
91	c.report()
92	return err
93}
94
95func (c *Cmd) Output() ([]byte, error) {
96	c.prepare()
97	bytes, err := c.Cmd.Output()
98	c.report()
99	return bytes, err
100}
101
102func (c *Cmd) CombinedOutput() ([]byte, error) {
103	c.prepare()
104	bytes, err := c.Cmd.CombinedOutput()
105	c.report()
106	return bytes, err
107}
108
109func (c *Cmd) Wait() error {
110	err := c.Cmd.Wait()
111	c.report()
112	return err
113}
114
115// StartOrFatal is equivalent to Start, but handles the error with a call to ctx.Fatal
116func (c *Cmd) StartOrFatal() {
117	if err := c.Start(); err != nil {
118		c.ctx.Fatalf("Failed to run %s: %v", c.name, err)
119	}
120}
121
122func (c *Cmd) reportError(err error) {
123	if err == nil {
124		return
125	}
126	if e, ok := err.(*exec.ExitError); ok {
127		c.ctx.Fatalf("%s failed with: %v", c.name, e.ProcessState.String())
128	} else {
129		c.ctx.Fatalf("Failed to run %s: %v", c.name, err)
130	}
131}
132
133// RunOrFatal is equivalent to Run, but handles the error with a call to ctx.Fatal
134func (c *Cmd) RunOrFatal() {
135	c.reportError(c.Run())
136}
137
138// WaitOrFatal is equivalent to Wait, but handles the error with a call to ctx.Fatal
139func (c *Cmd) WaitOrFatal() {
140	c.reportError(c.Wait())
141}
142
143// OutputOrFatal is equivalent to Output, but handles the error with a call to ctx.Fatal
144func (c *Cmd) OutputOrFatal() []byte {
145	ret, err := c.Output()
146	c.reportError(err)
147	return ret
148}
149
150// CombinedOutputOrFatal is equivalent to CombinedOutput, but handles the error with
151// a call to ctx.Fatal
152func (c *Cmd) CombinedOutputOrFatal() []byte {
153	ret, err := c.CombinedOutput()
154	c.reportError(err)
155	return ret
156}
157
158// RunAndPrintOrFatal will run the command, then after finishing
159// print any output, then handling any errors with a call to
160// ctx.Fatal
161func (c *Cmd) RunAndPrintOrFatal() {
162	ret, err := c.CombinedOutput()
163	st := c.ctx.Status.StartTool()
164	if len(ret) > 0 {
165		if err != nil {
166			st.Error(string(ret))
167		} else {
168			st.Print(string(ret))
169		}
170	}
171	st.Finish()
172	c.reportError(err)
173}
174
175// RunAndStreamOrFatal will run the command, while running print
176// any output, then handle any errors with a call to ctx.Fatal
177func (c *Cmd) RunAndStreamOrFatal() {
178	out, err := c.StdoutPipe()
179	if err != nil {
180		c.ctx.Fatal(err)
181	}
182	c.Stderr = c.Stdout
183
184	st := c.ctx.Status.StartTool()
185
186	c.StartOrFatal()
187
188	buf := bufio.NewReaderSize(out, 2*1024*1024)
189	for {
190		// Attempt to read whole lines, but write partial lines that are too long to fit in the buffer or hit EOF
191		line, err := buf.ReadString('\n')
192		if line != "" {
193			st.Print(strings.TrimSuffix(line, "\n"))
194		} else if err == io.EOF {
195			break
196		} else if err != nil {
197			c.ctx.Fatal(err)
198		}
199	}
200
201	err = c.Wait()
202	st.Finish()
203	c.reportError(err)
204}
205