129 lines
4.5 KiB
Markdown
129 lines
4.5 KiB
Markdown
# Mock Driver
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This repo includes a mock task driver in the [`drivers/mock`][] package that
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implements a minimal task driver interface for development work. This driver is
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loaded as the other [built-in drivers][] are, but only when Nomad is [not
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compiled with the release tag][].
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## Task Configuration
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```hcl
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task "mocktask" {
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driver = "mock_driver"
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config {
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run_for = "10s"
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exit_code = 7
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exit_err_msg = "the application crashed"
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}
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}
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```
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The `mock_driver` driver supports the following configuration in the job spec:
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- `run_for` `(duration: "0s")` - The duration for which the fake task runs
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for. After this period the driver responds indicating the task has terminated.
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- `signal_error` `(string: "")` - The error message the task returns if signalled.
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- `stderr_repeat_duration` `(duration: "0s")` - The duration between repeated stderr outputs.
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- `stderr_repeat` `(number: 0)` - The number of times the `stderr_string` will be written.
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- `stderr_string` `(string: "")` - The string that the task writes to stderr.
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- `stdout_repeat_duration` `(string: "")` - The duration between repeated stdout outputs.
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- `stdout_repeat` `(number: 0)` - The number of times the `stdout_string` will be written.
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- `stdout_string` `(string: "")` - The string that the task writes to stdout.
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The driver has configurable startup and shutdown for the tasks:
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- `exit_code` `(number: 0)` - The exit code the driver should return for the exiting task.
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- `exit_err_msg` `(string: "")` - The error message the task returns while exiting.
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- `exit_signal` `(number: 0)` - The signal with which the driver indicates the
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task has been killed.
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- `kill_after` `(duration: "0s")` - Duration after which the driver indicates
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the task has exited with `SIGINT`.
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- `plugin_exit_after` `(string: "")` - Duration after which the driver indicates
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the plugin exited via the `WaitTask` call.
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- `start_block_for` `(duration: "0s")` - Duration to block before returning when started.
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- `start_error_recoverable` `(bool: false)` - Marks whether the error returned
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when starting the driver is recoverable.
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- `start_error` `(string: "")` - The error that is returned when starting the driver.
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The driver can present information to the client about the task as though it had networking:
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- `driver_advertise` `(bool: false)` - Returned as `DriverNetwork.AutoAdvertise` from `Start()`
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- `driver_ip` `(string: "")` - The address returned as the `DriverNetwork.IP` from `Start()`
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- `driver_port_map` `(string: "")` - Parse a label:number pair and return it as
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`DriverNetwork.PortMap` from `Start()`.
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## Plugin Options
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```hcl
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plugin "mock_driver" {
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fs_isolation = "none"
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shutdown_periodic_after = false
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shutdown_periodic_duration = 0
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}
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```
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- `fs_isolation` `(string: "none")` - The type of file system isolation to
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report to the client. Must be one of `"none"`, `"chroot"`, or `"image"`.
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- `shutdown_periodic_after` `(bool: false)` - A toggle that can be used during
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tests to "stop" a previously-functioning driver, allowing for testing of
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periodic drivers and fingerprinters.
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- `shutdown_periodic_duration` `(number: 0)` - The duration after which to stop
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a previously-functioning driver, in seconds.
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## Example
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An example job that could be used for testing task `kill_timeout`:
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```
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job "mock" {
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group "group" {
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task "task" {
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driver = "mock_driver"
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kill_timeout = "5s"
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config {
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exit_code = 0
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exit_err_msg = "error on exit"
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exit_signal = 9
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kill_after = "3s"
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run_for = "30s"
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signal_error = "got signal"
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start_block_for = "1s"
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stdout_repeat = 1
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stdout_repeat_duration = "10s"
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stdout_string = "hello, world!\n"
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}
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resources {
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cpu = 128
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memory = 128
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}
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}
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}
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}
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```
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This results in the following allocation events:
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```
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Recent Events:
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Time Type Description
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2023-03-20T16:22:39-04:00 Restarting Task restarting in 17.426443129s
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2023-03-20T16:22:39-04:00 Terminated Exit Code: 0, Signal: 9, Exit Message: "error on exit"
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2023-03-20T16:22:09-04:00 Started Task started by client
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2023-03-20T16:22:07-04:00 Task Setup Building Task Directory
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2023-03-20T16:22:07-04:00 Received Task received by client
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```
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[built-in drivers]: https://github.com/hashicorp/nomad/blob/main/helper/pluginutils/catalog/register.go
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[not compiled with the release tag]: https://github.com/hashicorp/nomad/blob/main/helper/pluginutils/catalog/register_testing.go
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[`drivers/mock`]: https://github.com/hashicorp/nomad/tree/main/drivers/mock
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