Update chain specs periodically through the CI

.github/workflows/update-chain-specs.yml

@@ -0,0 +1,82 @@
+name: chain-specs-periodic-update
+
+on:
+  push:
+    branches: [ tka-update-chain-specs-ci ]   # TODO: remove before merging, I'm just testing
+  schedule:
+    - cron: '0 8 * * *'  # every day at 8am
+
+
+jobs:
+  download-spec:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        # This starts one parallel job for each of these addresses.
+        rpc-node-address: [
+          "wss://rpc.polkadot.io",
+          "wss://kusama-rpc.polkadot.io",
+          "wss://westend-rpc.polkadot.io",
+          "wss://rococo-rpc.polkadot.io"
+        ]
+      fail-fast: false   # Don't automatically cancel the jobs of the other RPC nodes if one fails
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        path: repo
+    - run: |
+        curl -L -O https://github.com/vi/websocat/releases/download/v1.9.0/websocat_linux64
+        chmod +x websocat_linux64
+    - run: |
+        echo '{"id":1,"jsonrpc":"2.0","method":"sync_state_genSyncSpec","params":[true]}' |
+          ./websocat_linux64 -n1 -B 99999999 ${{ matrix.rpc-node-address }} |
+          jq .result > chain_spec.json
+    - id: get-chain-id  # Reads the `id` field in the newly-downloaded chain spec
+      run: echo "::set-output name=id::`jq -r .id ./chain_spec.json`"
+    - run: |  # Overwrite the `lightSyncState` field of the existing chain spec with the value of spec that's been downloaded.
+        tmp=$(mktemp)
+        output=./repo/packages/connect/src/connector/specs/${{ steps.get-chain-id.outputs.id }}.json
+        jq --slurpfile downloaded ./chain_spec.json '.lightSyncState = $downloaded[0].lightSyncState' "$output" > "$tmp"
+        mv "$tmp" "$output"
+    - run: |  # Do the same as the previous step, but for the chain spec of the extension. This is done separately in case the spec is not the same with the one in `connect`
+        tmp=$(mktemp)
+        output=./repo/projects/extension/public/assets/${{ steps.get-chain-id.outputs.id }}.json
+        jq --slurpfile downloaded ./chain_spec.json '.lightSyncState = $downloaded[0].lightSyncState' "$output" > "$tmp"
+        mv "$tmp" "$output"
+    - uses: actions/upload-artifact@v3
+      with:
+        name: chain-spec-${{ steps.get-chain-id.outputs.id }}
+        # Note that passing `repo/**` maintains paths under `repo`. This is a bit of magic by the upload-artifact action.
+        path: |
+          repo/**/${{ steps.get-chain-id.outputs.id }}.json
+
+  create-pr:
+    runs-on: ubuntu-latest
+    if: ${{ always() }}   # Run this job even if one of the steps of download-spec has failed
+    needs: download-spec
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        path: repo
+    - uses: actions/download-artifact@v3
+      with:
+        # Since we're not passing a name, this automatically downloads *all* artifacts
+        # Unfortunately, this creates intermediary directories.
+        path: .
+    - run: cp -r ./chain-spec-*/* ./repo
+    - uses: peter-evans/create-pull-request@v4
+      with:
+        path: repo
+        branch: automatic-checkpoints-update
+        title: Update checkpoints in chain specifications
+        # Note that the `download-spec` job above fails if the downloaded specification doesn't
+        # correspond to an existing file. It is therefore impossible that the pull request
+        # accidentally adds new specifications.
+        body: >
+          This pull request has been automatically generated by downloading chain
+          specifications from various JSON-RPC endpoints and extracting their checkpoints.
+        commit-message: Update checkpoints in chain specifications
+        delete-branch: true