@spec cmd(
  binary(),
  [binary() | {:secret, binary()} | [binary() | {:secret, binary()}]],
  keyword()
) :: {Collectable.t(), exit_status :: non_neg_integer()}

A wrapper around System.cmd/3 which additionally logs executed command, args and env.

If URL is found in logged message, then password in it is masked with asterisks. Additionally, it is possible to explicitly mark env values and arguments as secret for safe logging. See examples for details.

Examples

> Owl.System.cmd("echo", ["test"])
# 10:25:34.252 [debug] $ echo test
{"test\n", 0}

# marking an argument as secret
> Owl.System.cmd("echo", ["hello", secret: "world"])
# 10:25:40.516 [debug] $ echo hello ********
{"hello world\n", 0}

# marking a part of an argument as secret
> Owl.System.cmd("echo", ["hello", ["--password=", {:secret, "world"}]])
# 10:25:40.516 [debug] $ echo hello --password=********
{"hello --password=world\n", 0}

# marking a env as secret
> Owl.System.cmd("echo", ["hello", "world"], env: [{"PASSWORD", {:secret, "mypassword"}}])
# 10:25:40.516 [debug] $ PASSWORD=******** sh -c "echo hello world"
{"hello world\n", 0}

> Owl.System.cmd("psql", ["postgresql://postgres:postgres@127.0.0.1:5432", "-tAc", "SELECT 1;"])
# 10:25:50.947 [debug] $ psql postgresql://postgres:********@127.0.0.1:5432 -tAc 'SELECT 1;'
{"1\n", 0}

@spec daemon_cmd(
  binary(),
  [binary() | {:secret, binary()} | [binary() | {:secret, binary()}]],
  (-> result),
  prefix: Owl.Data.t(),
  device: IO.device(),
  ready_check: (String.t() -> boolean()),
  env: [{binary(), binary() | {:secret, binary()} | nil}]
) :: result
when result: any()

Runs command as a daemon, executes operation and kills the daemon afterwards.

Automatically puts messages from stderr and stdout to device prepending them with prefix. Returns result of invoking operation.

Options

• :prefix - a prefix for stderr and stdout messages from daemon. Defaults to command followed by colon.
• :device - device to which messages from stderr and stdout are put. Defaults to :stdio.
• :ready_check - a function which checks the content of the messages produced by command before writing to device. If the function is set, then the execution of the operation will be blocked until ready_check returns true. By default this check is absent and operation is invoked immediately without awaiting any message.
• :env - a list of tuples containing environment key-value. The behaviour is similar to the option described in cmd/3

Example

ex> Owl.System.daemon_cmd("ping", ["8.8.8.8"], fn ->
..>   Process.sleep(3_000)
..>   2 + 2
..> end)
# 00:36:33.963 [debug] $ ping 8.8.8.8
#
# 00:36:33.964 [debug] Started daemon ping with OS pid 576077
# ping:  PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
# ping:  64 bytes from 8.8.8.8: icmp_seq=1 ttl=118 time=28.3 ms
# ping:  64 bytes from 8.8.8.8: icmp_seq=2 ttl=118 time=26.9 ms
# ping:  64 bytes from 8.8.8.8: icmp_seq=3 ttl=118 time=28.6 ms

# 00:36:36.965 [debug] $ kill 576077
4

ex> Owl.System.daemon_cmd(
..>   "kubectl",
..>   [
..>     "port-forward",
..>     "--namespace=my-app",
..>     "--kubeconfig",
..>     "~/.kube/myapp",
..>     "my-pod",
..>     "5432:5432"
..>   ],
..>   fn ->
..>     Logger.debug("Dump DB")
..>   end,
..>   prefix: "kubectl(my-pod): ",
..>   ready_check: &String.contains?(&1, "Forwarding from")
..> )
# 12:08:01.382 [debug] $ kubectl port-forward --namespace=my-app --kubeconfig ~/.kube/myapp my-pod 5432:5432
# 12:08:01.384 [debug] Started daemon kubectl with OS pid 166378
# kubectl(my-pod): Forwarding from 127.0.0.1:5432 -> 5432
# kubectl(my-pod): Forwarding from [::1]:5432 -> 5432
# 12:08:02.484 [debug] Dump DB
# 12:08:02.584 [debug] $ kill 166378
:ok

@spec shell(
  binary(),
  keyword()
) :: {Collectable.t(), exit_status :: non_neg_integer()}

A wrapper around System.shell/2 which additionally logs executed command.

Similarly to cmd/3, it automatically hides password in found URLs and allows manual hiding of env values.

Examples

> Owl.System.shell("echo hello world")
# 22:36:01.440 [debug] $ sh -c "echo hello world"
{"hello world\n", 0}

> Owl.System.shell("echo postgresql://postgres:postgres@127.0.0.1:5432")
# 22:36:51.797 [debug] $ sh -c "echo postgresql://postgres:********@127.0.0.1:5432"
{"postgresql://postgres:postgres@127.0.0.1:5432\n", 0}

> Owl.System.shell("echo $PASSWORD $USERNAME", env: [{"USERNAME", "john"}, {"PASSWORD", {:secret, "qwerty"}}])
# 12:38:27.704 [debug] $ USERNAME=john PASSWORD=******** sh -c "echo \$PASSWORD \$USERNAME"
{"qwerty john\n", 0}