Files: 6340d659d6042b83150caf838e14096122df163c / index.js
4588 bytesRaw
1 | const Tree = require('merkle-radix-tree') |
2 | const Graph = require('ipld-graph-builder') |
3 | const Kernel = require('./kernel.js') |
4 | const Scheduler = require('./scheduler.js') |
5 | const DFSchecker = require('./dfsChecker.js') |
6 | const CreationService = require('./creationService.js') |
7 | |
8 | const CREATION_ID = 0 |
9 | |
10 | module.exports = class Hypervisor { |
11 | /** |
12 | * The Hypervisor manages the container instances by instantiating them and |
13 | * destorying them when possible. It also facilitates localating Containers |
14 | * @param {Graph} dag an instance of [ipfs.dag](https://github.com/ipfs/interface-ipfs-core/tree/master/API/dag#dag-api) |
15 | * @param {object} state - the starting state |
16 | */ |
17 | constructor (dag, state = {'/': Tree.emptyTreeState}) { |
18 | this.graph = new Graph(dag) |
19 | this.tree = new Tree({ |
20 | graph: this.graph, |
21 | root: state |
22 | }) |
23 | this.scheduler = new Scheduler() |
24 | this.state = state |
25 | this._containerTypes = {} |
26 | this._nodesToCheck = new Set() |
27 | |
28 | this.creationService = new CreationService({ |
29 | hypervisor: this |
30 | }) |
31 | this.scheduler.systemServices.set(CREATION_ID, this.creationService) |
32 | this.pinnedIds = new Set() |
33 | } |
34 | |
35 | /** |
36 | * add a potaintail node in the state graph to check for garbage collection |
37 | * @param {string} id |
38 | */ |
39 | addNodeToCheck (id) { |
40 | this._nodesToCheck.add(id) |
41 | } |
42 | |
43 | /** |
44 | * given a port, this finds the corridsponeding endpoint port of the channel |
45 | * @param {object} port |
46 | * @returns {Promise} |
47 | */ |
48 | async getDestPort (port) { |
49 | if (port.destPort) { |
50 | return port.destPort |
51 | } else { |
52 | const instance = await this.scheduler.getInstance(port.destId) |
53 | let containerState |
54 | if (instance) { |
55 | containerState = instance.state |
56 | } else { |
57 | containerState = await this.tree.get(port.destId) |
58 | } |
59 | return this.graph.get(containerState, `ports/${port.destName}`) |
60 | } |
61 | } |
62 | |
63 | async send (port, message) { |
64 | const id = port.destId |
65 | if (id !== undefined) { |
66 | const instance = await this.getInstance(id) |
67 | return instance.queue(port, message) |
68 | } else { |
69 | // port is unbound |
70 | port.destPort.messages.push(message) |
71 | } |
72 | } |
73 | |
74 | // loads an instance of a container from the state |
75 | async _loadInstance (id, state) { |
76 | if (!state) { |
77 | state = await this.tree.get(id) |
78 | } |
79 | const container = this._containerTypes[state.type] |
80 | let code |
81 | |
82 | // checks if the code stored in the state is an array and that the elements |
83 | // are merkle link |
84 | if (state.code && state.code[0]['/']) { |
85 | await this.graph.tree(state.code, 1) |
86 | code = state.code.map(a => a['/']).reduce((a, b) => a + b) |
87 | } else { |
88 | code = state.code |
89 | } |
90 | |
91 | // create a new kernel instance |
92 | const kernel = new Kernel({ |
93 | hypervisor: this, |
94 | state: state, |
95 | code: code, |
96 | container: container, |
97 | id: id |
98 | }) |
99 | |
100 | // save the newly created instance |
101 | this.scheduler.update(kernel) |
102 | return kernel |
103 | } |
104 | |
105 | /** |
106 | * gets an existsing container instances |
107 | * @param {string} id - the containers ID |
108 | * @returns {Promise} |
109 | */ |
110 | async getInstance (id) { |
111 | let instance = this.scheduler.getInstance(id) |
112 | if (instance) { |
113 | return instance |
114 | } else { |
115 | const resolve = this.scheduler.lock(id) |
116 | const instance = await this._loadInstance(id) |
117 | await instance.startup() |
118 | resolve(instance) |
119 | return instance |
120 | } |
121 | } |
122 | |
123 | createChannel () { |
124 | const port1 = { |
125 | messages: [] |
126 | } |
127 | |
128 | const port2 = { |
129 | messages: [], |
130 | destPort: port1 |
131 | } |
132 | |
133 | port1.destPort = port2 |
134 | return [port1, port2] |
135 | } |
136 | |
137 | /** |
138 | * creates a state root starting from a given container and a given number of |
139 | * ticks |
140 | * @param {Number} ticks the number of ticks at which to create the state root |
141 | * @returns {Promise} |
142 | */ |
143 | async createStateRoot (ticks) { |
144 | await this.scheduler.wait(ticks) |
145 | |
146 | const unlinked = await DFSchecker(this.tree, this._nodesToCheck, (id) => { |
147 | return this.pinnedIds.has(id) |
148 | }) |
149 | for (const id of unlinked) { |
150 | await this.tree.delete(id) |
151 | } |
152 | return this.graph.flush(this.state) |
153 | } |
154 | |
155 | /** |
156 | * regirsters a container with the hypervisor |
157 | * @param {Class} Constructor - a Class for instantiating the container |
158 | * @param {*} args - any args that the contructor takes |
159 | * @param {interger} typeId - the container's type identification ID |
160 | */ |
161 | registerContainer (Constructor, args, typeId = Constructor.typeId) { |
162 | this._containerTypes[typeId] = { |
163 | Constructor: Constructor, |
164 | args: args |
165 | } |
166 | } |
167 | |
168 | pin (instance) { |
169 | this.pinnedIds.add(instance.id) |
170 | } |
171 | } |
172 |
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