1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

use crate::epi::channel::{JsonMessageReceiver, JsonMessageSender};
use crate::parameter::ParamValue;
use crate::problem::ProblemSpec;
use crate::solver::{ObservedObs, Solver, SolverRecipe, SolverSpec, UnobservedObs};
use crate::{Error, ErrorKind, Result};
use rand::Rng;
use rustats::num::FiniteF64;
use serde::{Deserialize, Serialize};
use std::io::{BufReader, BufWriter};
use std::path::PathBuf;
use std::process::{Child, ChildStdin, ChildStdout, Command, Stdio};
use structopt::StructOpt;
use yamakan::budget::{Budget, Budgeted};
use yamakan::observation::{IdGen, Obs, ObsId};

#[derive(Debug, Clone, StructOpt, Serialize, Deserialize)]
#[structopt(rename_all = "kebab-case")]
#[serde(rename_all = "kebab-case")]
pub struct ExternalProgramSolverRecipe {
    pub path: PathBuf,
    pub args: Vec<String>,
}
impl SolverRecipe for ExternalProgramSolverRecipe {
    type Solver = ExternalProgramSolver;

    fn create_solver(&self, problem: ProblemSpec) -> Result<Self::Solver> {
        let mut child = track!(Command::new(&self.path)
            .args(&self.args)
            .stdin(Stdio::piped())
            .stdout(Stdio::piped())
            .spawn()
            .map_err(Error::from))?;

        let stdin = BufWriter::new(track_assert_some!(child.stdin.take(), ErrorKind::IoError));
        let stdout = BufReader::new(track_assert_some!(child.stdout.take(), ErrorKind::IoError));

        let mut tx = JsonMessageSender::new(stdin);
        let mut rx = JsonMessageReceiver::new(stdout);
        let spec = match track!(rx.recv())? {
            SolverMessage::SolverSpecCast(m) => m,
            m => track_panic!(ErrorKind::InvalidInput, "Unexpected message: {:?}", m),
        };

        // TODO: check capabilities
        track!(tx.send(&SolverMessage::ProblemSpecCast(problem.clone())))?;

        Ok(ExternalProgramSolver {
            spec,
            child,
            tx,
            rx,
        })
    }
}

#[derive(Debug)]
pub struct ExternalProgramSolver {
    spec: SolverSpec,
    child: Child,
    tx: JsonMessageSender<SolverMessage, BufWriter<ChildStdin>>,
    rx: JsonMessageReceiver<SolverMessage, BufReader<ChildStdout>>,
}
impl Solver for ExternalProgramSolver {
    fn specification(&self) -> SolverSpec {
        self.spec.clone()
    }

    fn ask<R: Rng, G: IdGen>(&mut self, _rng: &mut R, idg: &mut G) -> Result<UnobservedObs> {
        let id_hint = track!(idg.generate())?;
        let message = SolverMessage::AskCall { id_hint };
        track!(self.tx.send(&message))?;

        match track!(self.rx.recv())? {
            SolverMessage::AskReply { id, params, budget } => {
                let obs = Obs {
                    id,
                    param: Budgeted::new(budget, params),
                    value: (),
                };
                Ok(obs)
            }
            SolverMessage::ErrorReply { kind, message } => {
                if let Some(message) = message {
                    track_panic!(kind, "{}", message);
                } else {
                    track_panic!(kind);
                }
            }
            m => track_panic!(ErrorKind::InvalidInput, "Unexpected message: {:?}", m),
        }
    }

    fn tell(&mut self, obs: ObservedObs) -> Result<()> {
        let message = SolverMessage::TellCall {
            id: obs.id,
            budget: obs.param.budget(),
            params: obs.param.into_inner(),
            values: obs.value,
        };
        track!(self.tx.send(&message))?;

        match track!(self.rx.recv())? {
            SolverMessage::TellReply => Ok(()),
            SolverMessage::ErrorReply { kind, message } => {
                if let Some(message) = message {
                    track_panic!(kind, "{}", message);
                } else {
                    track_panic!(kind);
                }
            }
            m => track_panic!(ErrorKind::InvalidInput, "Unexpected message: {:?}", m),
        }
    }
}
impl Drop for ExternalProgramSolver {
    fn drop(&mut self) {
        if self.child.kill().is_ok() {
            let _ = self.child.wait(); // for preventing the child process becomes a zombie.
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "SCREAMING_SNAKE_CASE")]
pub enum SolverMessage {
    SolverSpecCast(SolverSpec),
    ProblemSpecCast(ProblemSpec),
    AskCall {
        id_hint: ObsId,
    },
    AskReply {
        id: ObsId,
        params: Vec<ParamValue>,
        budget: Budget,
    },
    TellCall {
        id: ObsId,
        params: Vec<ParamValue>,
        budget: Budget,
        values: Vec<FiniteF64>,
    },
    TellReply,
    ErrorReply {
        kind: ErrorKind,
        #[serde(default)]
        message: Option<String>,
    },
}