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diff --git a/lib/exile.ex b/lib/exile.ex
index f8cbcce..38a97ef 100644
--- a/lib/exile.ex
+++ b/lib/exile.ex
@@ -1,246 +1,272 @@
defmodule Exile do
@moduledoc ~S"""
Exile is an alternative for beam [ports](https://hexdocs.pm/elixir/Port.html)
with back-pressure and non-blocking IO.
### Quick Start
Run a command and read from stdout
```
iex> Exile.stream!(~w(echo Hello))
...> |> Enum.into("") # collect as string
"Hello\n"
```
Run a command with list of strings as input
```
iex> Exile.stream!(~w(cat), input: ["Hello", " ", "World"])
...> |> Enum.into("") # collect as string
"Hello World"
```
Run a command with input as Stream
```
iex> input_stream = Stream.map(1..10, fn num -> "#{num} " end)
iex> Exile.stream!(~w(cat), input: input_stream)
...> |> Enum.into("")
"1 2 3 4 5 6 7 8 9 10 "
```
Run a command with input as infinite stream
```
# create infinite stream
iex> input_stream = Stream.repeatedly(fn -> "A" end)
iex> binary =
...> Exile.stream!(~w(cat), input: input_stream, ignore_epipe: true) # we need to ignore epipe since we are terminating the program before the input completes
...> |> Stream.take(2) # we must limit since the input stream is infinite
...> |> Enum.into("")
iex> is_binary(binary)
true
iex> "AAAAA" <> _ = binary
```
Run a command with input Collectable
```
# Exile calls the callback with a sink where the process can push the data
iex> Exile.stream!(~w(cat), input: fn sink ->
...> Stream.map(1..10, fn num -> "#{num} " end)
...> |> Stream.into(sink) # push to the external process
...> |> Stream.run()
...> end)
...> |> Stream.take(100) # we must limit since the input stream is infinite
...> |> Enum.into("")
"1 2 3 4 5 6 7 8 9 10 "
```
When the command wait for the input stream to close
```
# base64 command wait for the input to close and writes data to stdout at once
iex> Exile.stream!(~w(base64), input: ["abcdef"])
...> |> Enum.into("")
"YWJjZGVm\n"
```
When the command exit with an error
```
iex> Exile.stream!(["sh", "-c", "exit 4"])
...> |> Enum.into("")
** (Exile.Process.Error) command exited with status: 4
```
With `max_chunk_size` set
```
iex> data =
...> Exile.stream!(~w(cat /dev/urandom), max_chunk_size: 100, ignore_epipe: true)
...> |> Stream.take(5)
...> |> Enum.into("")
iex> byte_size(data)
500
```
When input and output run at different rate
```
iex> input_stream = Stream.map(1..1000, fn num -> "X #{num} X\n" end)
iex> Exile.stream!(~w(grep 250), input: input_stream)
...> |> Enum.into("")
"X 250 X\n"
```
With stderr enabled
```
iex> Exile.stream!(["sh", "-c", "echo foo\necho bar >> /dev/stderr"], enable_stderr: true)
...> |> Enum.to_list()
[{:stdout, "foo\n"}, {:stderr, "bar\n"}]
```
- With stream_exit_status enabled
+ `stream!/2` variant raises non-zero exit as error
```
- iex> Exile.stream!(["sh", "-c", "echo 'foo' && exit 10"], stream_exit_status: true)
+ iex> Exile.stream!(["sh", "-c", "echo 'foo' && exit 10"])
+ ...> |> Enum.to_list()
+ ** (Exile.Process.Error) command exited with status: 10
+ ```
+
+ `stream/2` variant returns exit status as last element
+
+ ```
+ iex> Exile.stream(["sh", "-c", "echo 'foo' && exit 10"])
...> |> Enum.to_list()
[
"foo\n",
- {:exit_status, 10} # returns exit status of the program as last element
+ {:exit, {:status, 10}} # returns exit status of the program as last element
]
```
- For more details about stream API, see `Exile.stream!/2`.
+ For more details about stream API, see `Exile.stream!/2` and `Exile.stream/2`.
For more details about inner working, please check `Exile.Process`
documentation.
"""
use Application
@doc false
def start(_type, _args) do
opts = [
name: Exile.WatcherSupervisor,
strategy: :one_for_one
]
# We use DynamicSupervisor for cleaning up external processes on
# :init.stop or SIGTERM
DynamicSupervisor.start_link(opts)
end
@doc ~S"""
Runs the command with arguments and return an the stdout as lazily
Enumerable stream, similar to [`Stream`](https://hexdocs.pm/elixir/Stream.html).
First parameter must be a list containing command with arguments.
Example: `["cat", "file.txt"]`.
### Options
* `input` - Input can be either an `Enumerable` or a function which accepts `Collectable`.
* Enumerable:
```
# List
Exile.stream!(~w(base64), input: ["hello", "world"]) |> Enum.to_list()
# Stream
Exile.stream!(~w(cat), input: File.stream!("log.txt", [], 65_536)) |> Enum.to_list()
```
* Collectable:
If the input in a function with arity 1, Exile will call that function
with a `Collectable` as the argument. The function must *push* input to this
collectable. Return value of the function is ignored.
```
Exile.stream!(~w(cat), input: fn sink -> Enum.into(1..100, sink, &to_string/1) end)
|> Enum.to_list()
```
By defaults no input is sent to the command.
* `exit_timeout` - Duration to wait for external program to exit after completion
(when stream ends). Defaults to `:infinity`
* `max_chunk_size` - Maximum size of iodata chunk emitted by the stream.
Chunk size can be less than the `max_chunk_size` depending on the amount of
data available to be read. Defaults to `65_535`
* `enable_stderr` - When set to true, output stream will contain stderr data along
with stdout. Stream data will be of the form `{:stdout, iodata}` or `{:stderr, iodata}`
to differentiate different streams. Defaults to false. See example below
* `ignore_epipe` - When set to true, reader can exit early without raising error.
Typically writer gets `EPIPE` error on write when program terminate prematurely.
With `ignore_epipe` set to true this error will be ignored. This can be used to
match UNIX shell default behaviour. EPIPE is the error raised when the reader finishes
the reading and close output pipe before command completes. Defaults to `false`.
- * `stream_exit_status` - When set to true, exit status of the program is passed as
- last element of the stream. The element will be `{:exit_status, pos_integer()}` on normal
- exit or `{:error, :epipe}` in case of epipe error. By default if program exits with
- non-zero exit status then the `Exile.Process.Error` will be raised. Defaults to `false`.
-
Remaining options are passed to `Exile.Process.start_link/2`
+ If program exits with non-zero exit status then the `Exile.Process.Error` will be
+ raised.
+
### Examples
```
Exile.stream!(~w(ffmpeg -i pipe:0 -f mp3 pipe:1), input: File.stream!("music_video.mkv", [], 65_535))
|> Stream.into(File.stream!("music.mp3"))
|> Stream.run()
```
Stream with stderr
```
Exile.stream!(~w(ffmpeg -i pipe:0 -f mp3 pipe:1),
input: File.stream!("music_video.mkv", [], 65_535),
enable_stderr: true
)
|> Stream.transform(
fn ->
File.open!("music.mp3", [:write, :binary])
end,
fn elem, file ->
case elem do
{:stdout, data} ->
# write stdout data to a file
:ok = IO.binwrite(file, data)
{:stderr, msg} ->
# write stderr output to console
:ok = IO.write(msg)
end
{[], file}
end,
fn file ->
:ok = File.close(file)
end
)
|> Stream.run()
```
"""
@type collectable_func() :: (Collectable.t() -> any())
@spec stream!(nonempty_list(String.t()),
input: Enum.t() | collectable_func(),
exit_timeout: timeout(),
enable_stderr: boolean(),
ignore_epipe: boolean(),
- max_chunk_size: pos_integer(),
- stream_exit_status: boolean()
+ max_chunk_size: pos_integer()
) :: Exile.Stream.t()
def stream!(cmd_with_args, opts \\ []) do
- Exile.Stream.__build__(cmd_with_args, opts)
+ Exile.Stream.__build__(cmd_with_args, Keyword.put(opts, :stream_exit_status, false))
+ end
+
+ @doc ~S"""
+ Same as `Exile.stream!/2` but the program exit status is passed as last
+ element of the stream.
+
+ The last element will be of the form `{:exit, term()}`. `term` will be a
+ positive integer in case of normal exit and `:epipe` in case of epipe error
+
+ See `Exile.stream!/2` documentation for details about the options and
+ examples.
+ """
+ @spec stream(nonempty_list(String.t()),
+ input: Enum.t() | collectable_func(),
+ exit_timeout: timeout(),
+ enable_stderr: boolean(),
+ ignore_epipe: boolean(),
+ max_chunk_size: pos_integer()
+ ) :: Exile.Stream.t()
+ def stream(cmd_with_args, opts \\ []) do
+ Exile.Stream.__build__(cmd_with_args, Keyword.put(opts, :stream_exit_status, true))
end
end
diff --git a/test/exile_test.exs b/test/exile_test.exs
index 3ba8d96..be9709f 100644
--- a/test/exile_test.exs
+++ b/test/exile_test.exs
@@ -1,98 +1,106 @@
defmodule ExileTest do
use ExUnit.Case
doctest Exile
test "stream with enumerable" do
proc_stream =
Exile.stream!(["cat"], input: Stream.map(1..1000, fn _ -> "a" end), enable_stderr: false)
stdout = proc_stream |> Enum.to_list()
assert IO.iodata_length(stdout) == 1000
end
test "stream with collectable" do
proc_stream =
Exile.stream!(["cat"], input: fn sink -> Enum.into(1..1000, sink, fn _ -> "a" end) end)
stdout = Enum.to_list(proc_stream)
assert IO.iodata_length(stdout) == 1000
end
test "stream without stdin" do
proc_stream = Exile.stream!(~w(echo hello))
stdout = Enum.to_list(proc_stream)
assert IO.iodata_to_binary(stdout) == "hello\n"
end
test "stderr" do
proc_stream = Exile.stream!(["sh", "-c", "echo foo >>/dev/stderr"], enable_stderr: true)
assert {[], stderr} = split_stream(proc_stream)
assert IO.iodata_to_binary(stderr) == "foo\n"
end
test "multiple streams" do
script = """
for i in {1..1000}; do
echo "foo ${i}"
echo "bar ${i}" >&2
done
"""
proc_stream = Exile.stream!(["sh", "-c", script], enable_stderr: true)
{stdout, stderr} = split_stream(proc_stream)
stdout_lines = String.split(Enum.join(stdout), "\n", trim: true)
stderr_lines = String.split(Enum.join(stderr), "\n", trim: true)
assert length(stdout_lines) == length(stderr_lines)
assert Enum.all?(stdout_lines, &String.starts_with?(&1, "foo "))
assert Enum.all?(stderr_lines, &String.starts_with?(&1, "bar "))
end
test "environment variable" do
output =
Exile.stream!(~w(printenv FOO), env: %{"FOO" => "bar"})
|> Enum.to_list()
|> IO.iodata_to_binary()
assert output == "bar\n"
end
test "premature stream termination" do
input_stream = Stream.map(1..100_000, fn _ -> "hello" end)
assert_raise Exile.Process.Error,
"abnormal command exit, received EPIPE while writing to stdin",
fn ->
Exile.stream!(~w(cat), input: input_stream)
|> Enum.take(1)
end
end
test "premature stream termination when ignore_epipe is true" do
input_stream = Stream.map(1..100_000, fn _ -> "hello" end)
assert ["hello"] ==
Exile.stream!(~w(cat), input: input_stream, ignore_epipe: true, max_chunk_size: 5)
|> Enum.take(1)
end
- test "stream with stream_exit_status option" do
- proc_stream = Exile.stream!(["sh", "-c", "exit 10"], stream_exit_status: true)
+ test "stream!/2 with exit status" do
+ proc_stream = Exile.stream!(["sh", "-c", "exit 10"])
+
+ assert_raise Exile.Process.Error, "command exited with status: 10", fn ->
+ Enum.to_list(proc_stream)
+ end
+ end
+
+ test "stream/2 with exit status" do
+ proc_stream = Exile.stream(["sh", "-c", "exit 10"])
stdout = Enum.to_list(proc_stream)
- assert stdout == [{:exit_status, 10}]
+ assert stdout == [{:exit, {:status, 10}}]
end
defp split_stream(stream) do
{stdout, stderr} =
Enum.reduce(stream, {[], []}, fn
{:stdout, data}, {stdout, stderr} -> {[data | stdout], stderr}
{:stderr, data}, {stdout, stderr} -> {stdout, [data | stderr]}
end)
{Enum.reverse(stdout), Enum.reverse(stderr)}
end
end

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