add deep persistence example

examples/deep-persistence-with-restore/.gitignore

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+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?

examples/deep-persistence-with-restore/actors.ts

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+import { fromPromise } from 'xstate';
+import { RunServiceMachine } from './machines';
+
+export async function delay(
+  ms: number,
+  errorProbability: number = 0
+): Promise<void> {
+  return new Promise((resolve, reject) => {
+    setTimeout(() => {
+      if (Math.random() < errorProbability) {
+        reject({ type: 'ServiceNotAvailable' });
+      } else {
+        resolve();
+      }
+    }, ms);
+  });
+}
+
+export function createActors(errorProbability = 0.6) {
+  const services: Record<string, any> = {
+    'up-step1-system1': fromPromise(async () => {
+      const resp = await delay(1000);
+      return resp;
+    }),
+    'up-step2-system1': fromPromise(async () => {
+      const resp = await delay(1000, errorProbability);
+      return resp;
+    }),
+    'up-step3-system2': fromPromise(async () => {
+      const resp = await delay(1000);
+      return resp;
+    }),
+    'up-step4-system1': fromPromise(async () => {
+      const resp = await delay(1000);
+      return resp;
+    }),
+    'up-step5-system3': fromPromise(async () => {
+      const resp = await delay(1000);
+      return resp;
+    }),
+    'down-step1-system1': fromPromise(async () => {
+      const resp = await delay(1000);
+      return resp;
+    }),
+    'down-step2-system2': fromPromise(async () => {
+      const resp = await delay(1000);
+      return resp;
+    }),
+    'down-step3-system3': fromPromise(async () => {
+      const resp = await delay(1000);
+      return resp;
+    })
+  };
+
+  const actors: Record<string, any> = {};
+  Object.keys(services).forEach(
+    (key) =>
+      (actors[key] = RunServiceMachine.provide({
+        actors: { upDownService: services[key] }
+      }))
+  );
+
+  return actors;
+}

examples/deep-persistence-with-restore/historyStates.json

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+[
+  {
+    "status": "active",
+    "value": { "Up": "Done" },
+    "historyValue": {},
+    "context": {},
+    "children": {}
+  },
+  {
+    "status": "active",
+    "value": { "Up": "Step5 system3" },
+    "historyValue": {},
+    "context": {},
+    "children": {
+      "up-step5-system3": {
+        "snapshot": {
+          "status": "active",
+          "value": "running",
+          "historyValue": {},
+          "context": { "errorCount": 0, "threshold": 3 },
+          "children": {
+            "upDownService": {
+              "snapshot": { "status": "active" },
+              "src": "upDownService",
+              "syncSnapshot": false
+            }
+          }
+        },
+        "src": "up-step5-system3",
+        "syncSnapshot": false
+      }
+    }
+  },
+  {
+    "status": "active",
+    "value": { "Up": "Step4 System1" },
+    "historyValue": {},
+    "context": {},
+    "children": {
+      "up-step4-system1": {
+        "snapshot": {
+          "status": "active",
+          "value": "running",
+          "historyValue": {},
+          "context": { "errorCount": 0, "threshold": 3 },
+          "children": {
+            "upDownService": {
+              "snapshot": { "status": "active" },
+              "src": "upDownService",
+              "syncSnapshot": false
+            }
+          }
+        },
+        "src": "up-step4-system1",
+        "syncSnapshot": false
+      }
+    }
+  },
+  {
+    "status": "active",
+    "value": { "Up": "Step3 system2" },
+    "historyValue": {},
+    "context": {},
+    "children": {
+      "up-step3-system2": {
+        "snapshot": {
+          "status": "active",
+          "value": "running",
+          "historyValue": {},
+          "context": { "errorCount": 0, "threshold": 3 },
+          "children": {
+            "upDownService": {
+              "snapshot": { "status": "active" },
+              "src": "upDownService",
+              "syncSnapshot": false
+            }
+          }
+        },
+        "src": "up-step3-system2",
+        "syncSnapshot": false
+      }
+    }
+  },
+  {
+    "status": "active",
+    "value": { "Up": "Step2 system1" },
+    "historyValue": {},
+    "context": {},
+    "children": {
+      "up-step2-system1": {
+        "snapshot": {
+          "status": "active",
+          "value": "running",
+          "historyValue": {},
+          "context": { "errorCount": 0, "threshold": 3 },
+          "children": {
+            "upDownService": {
+              "snapshot": { "status": "active" },
+              "src": "upDownService",
+              "syncSnapshot": false
+            }
+          }
+        },
+        "src": "up-step2-system1",
+        "syncSnapshot": false
+      }
+    }
+  },
+  {
+    "status": "done",
+    "value": "NotDone",
+    "historyValue": {},
+    "context": {},
+    "children": {}
+  },
+  {
+    "status": "active",
+    "value": { "Up": "Step2 system1" },
+    "historyValue": {},
+    "context": {},
+    "children": {
+      "up-step2-system1": {
+        "snapshot": {
+          "status": "active",
+          "value": "running",
+          "historyValue": {},
+          "context": { "errorCount": 0, "threshold": 3 },
+          "children": {
+            "upDownService": {
+              "snapshot": { "status": "active" },
+              "src": "upDownService",
+              "syncSnapshot": false
+            }
+          }
+        },
+        "src": "up-step2-system1",
+        "syncSnapshot": false
+      }
+    }
+  },
+  {
+    "status": "active",
+    "value": { "Up": "Step1 system1" },
+    "historyValue": {},
+    "context": {},
+    "children": {
+      "up-step1-system1": {
+        "snapshot": {
+          "status": "active",
+          "value": "running",
+          "historyValue": {},
+          "context": { "errorCount": 0, "threshold": 3 },
+          "children": {
+            "upDownService": {
+              "snapshot": { "status": "active" },
+              "src": "upDownService",
+              "syncSnapshot": false
+            }
+          }
+        },
+        "src": "up-step1-system1",
+        "syncSnapshot": false
+      }
+    }
+  }
+]

examples/deep-persistence-with-restore/machines/RunningServices.ts

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+import { assign, createMachine, sendParent } from 'xstate';
+
+type Context = {
+  errorCount: number;
+  threshold: number;
+};
+
+type Events = { type: 'Retry' };
+
+export const RunServiceMachine = createMachine(
+  {
+    id: 'Run Service',
+    initial: 'running',
+    types: {} as {
+      context: Context;
+      events: Events;
+    },
+    context: ({ input }) => {
+      return {
+        errorCount: 0,
+        threshold: input?.threshold ? input.threshold : 3
+      };
+    },
+    states: {
+      done: {
+        entry: ['logDone'],
+        type: 'final'
+      },
+      error: {
+        entry: ['logError', 'updateCounter'],
+        after: {
+          WaitBeforeRetry: [
+            { guard: 'exceedsThreshold', target: 'notDone' },
+            { target: 'running' }
+          ]
+        },
+        on: {
+          // Manual retry
+          Retry: {
+            target: 'running'
+          }
+        }
+      },
+      running: {
+        entry: ['init'],
+        invoke: {
+          src: 'upDownService',
+          id: 'upDownService',
+          onDone: [
+            {
+              target: 'done'
+            }
+          ],
+          onError: [
+            {
+              target: 'error'
+            }
+          ]
+        }
+      },
+      notDone: {
+        entry: ['logNotDone', sendParent({ type: 'NOT_DONE' })],
+        type: 'final'
+      }
+    }
+  },
+  {
+    delays: {
+      WaitBeforeRetry: 3000
+    },
+    actions: {
+      logNotDone: ({ self }) => console.log('---rs:  notDone', self.id),
+      logDone: ({ self }) => console.log('---rs:  done', self.id),
+      logError: ({ self }) => console.log('---rs: error', self.id),
+      logRunning: ({ self }) => console.log('---rs: init', self.id),
+      updateCounter: assign({
+        errorCount: ({ context }) => context.errorCount + 1
+      })
+    },
+    guards: {
+      exceedsThreshold: ({ context }) => {
+        return context.errorCount > 3;
+      }
+    }
+  }
+);