syndicate_utils/README.md

# Syndicate utils

## cache_actor

An actor that observes patterns and reässerts the values they capture for a given lifetime. Takes the arguments `{ dataspace: #!any lifetime: double }`. The lifetime of a cache counts down from moment a value is asserted.

Example configuration:
```
? <nixspace ?nixspace> [
  ; Require the nix_actor during observations.
  ?nixspace> ? <Observe <rec eval _> _> [
    $config <require-service <daemon nix_actor>> ]
  ?nixspace> ? <Observe <rec realise _> _> [
    $config <require-service <daemon nix_actor>> ]

  ; Cache anything captured by observers in the $nixspace for an hour.
  ; The nix_actor is not required during caching.
  $config ? <service-object <daemon cache_actor> ?cap> [
    $cap { dataspace: $nixspace lifetime: 3600.0 } ]
]
```

## json_translator

Wrapper that executes a command, parses its JSON output, converts to Preserves record `<recv @jsonData any>`, and publishes and messages to its initial dataspace.

## json_socket_translator

Utility to communicate with sockets that send and receive lines of JSON using `<send …>` and `<recv …>` messages. Compatible with [mpv](https://mpv.io/), see [mpv.config-example.pr](./mpv.config-example.pr).

Do not send messages immediately to the dataspace passed `json_socket_translator`, wait until it asserts `<connected @socketPath string>`.

## mintsturdyref

A utility for minting [Sturdyrefs](https://synit.org/book/operation/builtin/gatekeeper.html#sturdyrefs).

## mount_actor

Actor for mounting filesystems on Linux.

Sample Syndicate server script:
```
# Assert a file-system we want to mount.
<mount "/dev/sda3" "/boot" "vfat">

# Transform mount assertions into mount status observations.
? <mount ?source ?target ?fs> [
  ? <mount $source $target $fs _> [ ]
]

# Assert mounting succeded.
? <mount _ ?target _ #t> [
  <service-state <mountpoint $target> ready>
]
# Assert mount failed.
? <mount _ ?target _ <failure _>> [
  <service-state <mountpoint $target> failed>
]

# Assert the details into the machine dataspace.
? <machine-dataspace ?machine> [
  $config ? <mount ?source ?target ?fs ?status> [
    $machine <mount $source $target $fs $status>
  ]
]

# Require the mount_actor daemon.
<require-service <daemon mount_actor>>
<daemon mount_actor {
  argv: ["/home/emery/src/bin/mount_actor"]
  protocol: application/syndicate
}>

# Pass the daemon the config dataspace.
? <service-object <daemon mount_actor> ?cap> [
  $cap { dataspace: $config }
]
```

## msg

A utility that sends messages to `$SYNDICATE_ROUTE`.


## net_mapper

Publishes ICMP packet round-trip-times. See [net_mapper.prs](./net_mapper.prs) for a protocol description. [Source](./src/net_mapper.nim).

Example script:
```
? <machine-dataspace ?machine> [
  $machine ? <rtt "10.0.33.136" ?min ?avg ?max> [
    $log ! <log "-" { ping: { min: $min avg: $avg max: $max } }>
  ]

  $config [
    <require-service <daemon net_mapper>>
    <daemon net_mapper {
      argv: ["/bin/net_mapper"]
      protocol: application/syndicate
    }>
    ? <service-object <daemon net_mapper> ?cap> [
      $cap { dataspace: $machine }
    ]
  ]
]
```

## preserve_process_environment

This utility serializes it's process environment to Preserves and prints it to stdout.
It can be used to feed the environment variables of a nested child of the Syndicate server back to the server. For example, to retreive the environmental variables that a desktop manager passed on to its children.


## syndump

Utility for printing assertions and messages. Parses the command-line arguments as a pattern, connects a dataspace via `$SYNDICATE_ROUTE`, and writes observations to standard-output. Published assertions are prefixed by the `+` character, retractions by `-`, and messages by `!`.

Example
```sh
# Print patterns in use, filter down with AWK to only the published patterns.
$ FS=':' syndump '<Observe ? _>' | awk -F : '/^+/ { print $2 }'
```