In the `entrypoint.sh` script, we check if the MongoDB in use, has replicaSet initiated or not. This is usually done with a `rs.initiate()` on the cluster. We need the replicaSet to be enabled on MongoDB, since the backend server relies on MongoDB `changeStream`s, which is a feature, only available if replicaSet is enabled. However, to use the `changeStream` APIs, having the `read` or `readWrite` role on MongoDB is enough. But the check we do in `entrypoint.sh`, runs `rs.status()` to see if `replicaSet` is initiated. This `rs.status()` call, unfortunately, requires the `ClusterMonitor` role, unlike the `changeStream` API. To tackle this, we created the `appsmithctl check_replica_set` command. This command would attempt to use the `changeStream` API, and report success or failure. But this failed on certain configurations, where MongoDB was running as a single-node-cluster, on localhost, or a local/internal network. This was an edge case. That edge case is solved by this PR. With this, we can use `appsmithctl check-replica-set` in the `entrypoint.sh` again.
52 lines
1.2 KiB
JavaScript
52 lines
1.2 KiB
JavaScript
const { MongoClient } = require("mongodb");
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const { preprocessMongoDBURI } = require("./utils");
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async function exec() {
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const client = new MongoClient(preprocessMongoDBURI(process.env.APPSMITH_MONGODB_URI), {
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useNewUrlParser: true,
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useUnifiedTopology: true,
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});
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let isReplicaSetEnabled = false;
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try {
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isReplicaSetEnabled = await checkReplicaSet(client);
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} catch (err) {
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console.error("Error trying to check replicaset", err);
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} finally {
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await client.close();
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}
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process.exit(isReplicaSetEnabled ? 0 : 1);
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}
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async function checkReplicaSet(client) {
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await client.connect();
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return await new Promise((resolve) => {
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try {
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const changeStream = client
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.db()
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.collection("user")
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.watch()
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.on("change", (change) => console.log(change))
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.on("error", (err) => {
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console.error("Error even from changeStream", err);
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resolve(false);
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});
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// setTimeout so the error event can kick-in first
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setTimeout(() => {
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resolve(true);
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changeStream.close();
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}, 1000);
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} catch (err) {
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console.error("Error thrown when checking replicaset", err);
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resolve(false);
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}
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});
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}
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module.exports = {
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exec,
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};
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