harmos-runtime 0.1.2

Harmos runtime: managed state, undo, recovery, background work and typed streams.
Documentation 
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/* ***
 *
 * Harmos
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * ***
 */

/* === Modules === */

/* === Re-Exports === */

/* === Imports === */

// Standard Library Imports
use std::sync::Arc;
// Third Party Imports

// Local Imports
use super::contract;
use crate::sidecar::witness::Witness;
use contract::{POLICY, Probe, Queries, Read, Readings, Step};
use harmos_runtime::operations::Host as _;
use harmos_runtime::operations::{Operation, OperationPolicy, WireTable};
use harmos_runtime::sidecar::{Refusal, Supervisor};

/* === Constants === */

/* === Macros === */

/* === Type Aliases === */

/* === Structs === */

pub(crate) struct Client {
    resources: Arc<Witness>,
}

struct Probing {
    resources: Arc<Witness>,
}

/* === Enums === */

/* === Traits === */

/* === Implementations === */

impl harmos_runtime::operations::lifecycle::Policy for Client {
    const INITIALIZATION_POLICY: OperationPolicy = POLICY;
    const SHUTDOWN_POLICY: OperationPolicy = POLICY;
}

#[harmos_runtime::plugin(id = "process-client", provides = Queries, requires = Readings)]
impl harmos_runtime::Plugin for Client {
    type Context = Supervisor;
    type Config = String;
    type Error = Refusal;
    type Resources = Witness;

    fn prepare(key: String) -> Result<Self, Refusal> {
        Ok(Self { resources: Witness::find(&key).ok_or_else(|| Refusal::of("the story witness is gone"))? })
    }

    async fn initialize(&mut self, context: &Supervisor) -> Result<(), Refusal> {
        self.resources.mark("initializing");
        let response = context.call(Read { phase: 1 }).await.map_err(Refusal::from)?;
        if response.phase != 1 {
            return Err(Refusal::of("initialization used another provider response"));
        }
        self.resources.mark("dependency-initialized");
        if self.resources.seen("hold-initialization") {
            self.resources.marked("release-initialization").await;
        }
        self.resources.mark("initialized");
        Ok(())
    }

    fn resources(&self) -> Arc<Witness> {
        Arc::clone(&self.resources)
    }

    fn bind_operations(&self, table: &mut WireTable<Supervisor>) -> Result<(), harmos_runtime::operations::ServingError> {
        table.bind_operation::<Probing>(self.resources())
    }

    async fn stop(&mut self, context: &Supervisor) -> Result<(), Refusal> {
        let response = context.call(Read { phase: 2 }).await.map_err(Refusal::from)?;
        if response.phase != 2 {
            return Err(Refusal::of("shutdown used another provider response"));
        }
        self.resources.mark("dependency-shutdown");
        self.resources.mark("shutdown");
        Ok(())
    }

    async fn cleanup(&mut self) -> Result<(), Refusal> {
        self.resources.mark("cleaned");
        Ok(())
    }
}

impl Operation for Probing {
    type Declaration = Probe;
    type Resources = Witness;
    type Error = Refusal;
    type Endpoints = ();
    type Context<'a> = &'a Supervisor;

    async fn initialize<'ctx>(resources: Arc<Witness>, _context: Self::Context<'ctx>) -> Result<Self, Refusal> {
        let constructed: Result<Self, Refusal> = async move { Ok(Self { resources }) }.await;
        let mut operation = constructed?;
        let started: Result<(), Refusal> = async {
            let operation = &mut operation;
            operation.resources.mark("probe-initialized");
            Ok(())
        }
        .await;
        started?;
        Ok(operation)
    }

    async fn run<'ctx>(
        &mut self, _: Self::Context<'ctx>, request: &mut Probe, _endpoints: &mut Self::Endpoints,
    ) -> Result<harmos_runtime::operations::Response<Step>, Refusal> {
        let result: ::core::result::Result<Step, Self::Error> = async move {
            self.resources.mark("probe-started");
            Ok(Step { phase: request.phase })
        }
        .await;
        result.map(::core::convert::Into::into)
    }

    async fn cleanup(&mut self) -> Result<(), Refusal> {
        self.resources.mark("probe-finalized");
        Ok(())
    }
}

/* === Public Functions === */

/* === Private Functions === */

/* === Tests === */