|
| 1 | +package cmd |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "fmt" |
| 6 | + "io" |
| 7 | + "os" |
| 8 | + "os/exec" |
| 9 | + "regexp" |
| 10 | + "strings" |
| 11 | + "syscall" |
| 12 | + "time" |
| 13 | +) |
| 14 | + |
| 15 | +//Command represents a single command which can be executed |
| 16 | +type Command struct { |
| 17 | + Command string |
| 18 | + Env []string |
| 19 | + Dir string |
| 20 | + Timeout time.Duration |
| 21 | + StderrWriter io.Writer |
| 22 | + StdoutWriter io.Writer |
| 23 | + WorkingDir string |
| 24 | + executed bool |
| 25 | + stderr bytes.Buffer |
| 26 | + stdout bytes.Buffer |
| 27 | + exitCode int |
| 28 | +} |
| 29 | + |
| 30 | +//NewCommand creates a new command |
| 31 | +func NewCommand(cmd string, options ...func(*Command)) *Command { |
| 32 | + c := &Command{ |
| 33 | + Command: cmd, |
| 34 | + Timeout: 1 * time.Minute, |
| 35 | + executed: false, |
| 36 | + Env: []string{}, |
| 37 | + } |
| 38 | + |
| 39 | + c.StdoutWriter = &c.stdout |
| 40 | + c.StderrWriter = &c.stderr |
| 41 | + |
| 42 | + for _, o := range options { |
| 43 | + o(c) |
| 44 | + } |
| 45 | + |
| 46 | + return c |
| 47 | +} |
| 48 | + |
| 49 | +// WithStandardStreams creates a command which steams its output to the stderr and stdout streams of the operating system |
| 50 | +func WithStandardStreams(c *Command) { |
| 51 | + c.StdoutWriter = os.Stdout |
| 52 | + c.StderrWriter = os.Stderr |
| 53 | +} |
| 54 | + |
| 55 | +// AddEnv adds an environment variable to the command |
| 56 | +// If a variable gets passed like ${VAR_NAME} the env variable will be read out by the current shell |
| 57 | +func (c *Command) AddEnv(key string, value string) { |
| 58 | + vars := parseEnvVariableFromShell(value) |
| 59 | + for _, v := range vars { |
| 60 | + value = strings.Replace(value, v, os.Getenv(removeEnvVarSyntax(v)), -1) |
| 61 | + } |
| 62 | + |
| 63 | + c.Env = append(c.Env, fmt.Sprintf("%s=%s", key, value)) |
| 64 | +} |
| 65 | + |
| 66 | +// Removes the ${...} characters |
| 67 | +func removeEnvVarSyntax(v string) string { |
| 68 | + return v[2:(len(v) - 1)] |
| 69 | +} |
| 70 | + |
| 71 | +//Read all environment variables from the given value |
| 72 | +//with the syntax ${VAR_NAME} |
| 73 | +func parseEnvVariableFromShell(val string) []string { |
| 74 | + reg := regexp.MustCompile(`\$\{.*?\}`) |
| 75 | + matches := reg.FindAllString(val, -1) |
| 76 | + return matches |
| 77 | +} |
| 78 | + |
| 79 | +//SetTimeoutMS sets the timeout in milliseconds |
| 80 | +func (c *Command) SetTimeoutMS(ms int) { |
| 81 | + if ms == 0 { |
| 82 | + c.Timeout = 1 * time.Minute |
| 83 | + return |
| 84 | + } |
| 85 | + c.Timeout = time.Duration(ms) * time.Millisecond |
| 86 | +} |
| 87 | + |
| 88 | +// SetTimeout sets the timeout given a time unit |
| 89 | +// Example: SetTimeout("100s") sets the timeout to 100 seconds |
| 90 | +func (c *Command) SetTimeout(timeout string) error { |
| 91 | + d, err := time.ParseDuration(timeout) |
| 92 | + if err != nil { |
| 93 | + return err |
| 94 | + } |
| 95 | + |
| 96 | + c.Timeout = d |
| 97 | + return nil |
| 98 | +} |
| 99 | + |
| 100 | +//Stdout returns the output to stdout |
| 101 | +func (c *Command) Stdout() string { |
| 102 | + c.isExecuted("Stdout") |
| 103 | + return c.stdout.String() |
| 104 | +} |
| 105 | + |
| 106 | +//Stderr returns the output to stderr |
| 107 | +func (c *Command) Stderr() string { |
| 108 | + c.isExecuted("Stderr") |
| 109 | + return c.stderr.String() |
| 110 | +} |
| 111 | + |
| 112 | +//ExitCode returns the exit code of the command |
| 113 | +func (c *Command) ExitCode() int { |
| 114 | + c.isExecuted("ExitCode") |
| 115 | + return c.exitCode |
| 116 | +} |
| 117 | + |
| 118 | +//Executed returns if the command was already executed |
| 119 | +func (c *Command) Executed() bool { |
| 120 | + return c.executed |
| 121 | +} |
| 122 | + |
| 123 | +func (c *Command) isExecuted(property string) { |
| 124 | + if !c.executed { |
| 125 | + panic("Can not read " + property + " if command was not executed.") |
| 126 | + } |
| 127 | +} |
| 128 | + |
| 129 | +// Execute executes the command and writes the results into it's own instance |
| 130 | +// The results can be received with the Stdout(), Stderr() and ExitCode() methods |
| 131 | +func (c *Command) Execute() error { |
| 132 | + cmd := createBaseCommand(c) |
| 133 | + cmd.Env = c.Env |
| 134 | + cmd.Dir = c.Dir |
| 135 | + cmd.Stdout = c.StdoutWriter |
| 136 | + cmd.Stderr = c.StderrWriter |
| 137 | + cmd.Dir = c.WorkingDir |
| 138 | + |
| 139 | + err := cmd.Start() |
| 140 | + if err != nil { |
| 141 | + return err |
| 142 | + } |
| 143 | + |
| 144 | + done := make(chan error) |
| 145 | + go func() { |
| 146 | + done <- cmd.Wait() |
| 147 | + }() |
| 148 | + |
| 149 | + select { |
| 150 | + case err := <-done: |
| 151 | + if err != nil { |
| 152 | + c.getExitCode(err) |
| 153 | + break |
| 154 | + } |
| 155 | + c.exitCode = 0 |
| 156 | + case <-time.After(c.Timeout): |
| 157 | + if err := cmd.Process.Kill(); err != nil { |
| 158 | + return fmt.Errorf("Timeout occurred and can not kill process with pid %v", cmd.Process.Pid) |
| 159 | + } |
| 160 | + return fmt.Errorf("Command timed out after %v", c.Timeout) |
| 161 | + } |
| 162 | + |
| 163 | + //Remove leading and trailing whitespaces |
| 164 | + c.executed = true |
| 165 | + |
| 166 | + return nil |
| 167 | +} |
| 168 | + |
| 169 | +func (c *Command) getExitCode(err error) { |
| 170 | + if exitErr, ok := err.(*exec.ExitError); ok { |
| 171 | + if status, ok := exitErr.Sys().(syscall.WaitStatus); ok { |
| 172 | + c.exitCode = status.ExitStatus() |
| 173 | + } |
| 174 | + } |
| 175 | +} |
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