From 302db9b21bb3a0b595c6b53bd549c2a5111dc656 Mon Sep 17 00:00:00 2001
From: tilacog <tilacog@gmail.com>
Date: Tue, 24 Oct 2023 18:33:13 -0300
Subject: [PATCH] common: implement resolveGraftedSubgraphDeployment function

---
 packages/indexer-common/src/grafting.ts | 87 +++++++++++++++++++++----
 packages/indexer-common/src/types.ts    | 12 ++++
 2 files changed, 87 insertions(+), 12 deletions(-)

diff --git a/packages/indexer-common/src/grafting.ts b/packages/indexer-common/src/grafting.ts
index 1211c8a0a..e4a115a83 100644
--- a/packages/indexer-common/src/grafting.ts
+++ b/packages/indexer-common/src/grafting.ts
@@ -1,8 +1,23 @@
 import { SubgraphDeploymentID } from '@graphprotocol/common-ts'
 import { GraphNodeInterface } from './graph-node'
-import { BlockPointer, SubgraphManifest } from './types'
+import {
+  BlockPointer,
+  SubgraphDeploymentDecision,
+  SubgraphDeploymentDecisionKind,
+  SubgraphManifest,
+} from './types'
 import { indexerError, IndexerErrorCode } from './errors'
 
+type SubgraphManifestResolver = (
+  subgraphID: SubgraphDeploymentID,
+) => Promise<SubgraphManifest>
+
+interface IndexingStatus {
+  latestBlock: BlockPointer | null
+  health: string
+  synced: boolean
+}
+
 export interface GraftBase {
   block: number
   base: SubgraphDeploymentID
@@ -13,18 +28,17 @@ export interface GraftableSubgraph {
   graft: GraftBase | null // Root subgraph does not have a graft base
 }
 
-type SubgraphManifestResolver = (
-  subgraphID: SubgraphDeploymentID,
-) => Promise<SubgraphManifest>
-
-interface IndexingStatus {
-  latestBlock: BlockPointer | null
-  health: string
-  synced: boolean
+interface GraftableSubgraphStatus extends GraftableSubgraph {
+  indexingStatus: IndexingStatus | null
 }
 
-interface SubgraphGraftStatus extends GraftableSubgraph {
-  indexingStatus: IndexingStatus | null
+// TODO: use this type instead of a plain list.
+// Benefits: No need to check for graft base block on the adjacent sibling.
+interface SubgraphGraftLineage {
+  target: SubgraphDeploymentID
+  root: GraftBase
+  // list of descending graft bases, except the root.
+  bases: GraftBase[]
 }
 
 // Discovers all graft dependencies for a given subgraph
@@ -64,7 +78,7 @@ export async function discoverGraftBases(
 export async function getIndexingStatusOfGraftableSubgraph(
   subgraph: GraftableSubgraph,
   graphNode: GraphNodeInterface,
-): Promise<SubgraphGraftStatus> {
+): Promise<GraftableSubgraphStatus> {
   let response
   try {
     response = await graphNode.indexingStatus([subgraph.deployment])
@@ -88,3 +102,52 @@ export async function getIndexingStatusOfGraftableSubgraph(
   }
   return { ...subgraph, indexingStatus }
 }
+
+export function resolveGraftedSubgraphDeployment(
+  subgraphLineage: GraftableSubgraphStatus[],
+): SubgraphDeploymentDecision[] {
+  const deploymentDecisions: SubgraphDeploymentDecision[] = []
+
+  // Check lineage size before making any assumptions.
+  if (subgraphLineage.length < 2) {
+    throw new Error(
+      `Invalid input: Expected at least two members in graft lineage but got ${subgraphLineage.length}`,
+    )
+  }
+  // Check for any unsynced base.
+  // Iterate backwards while ignoring the target deployment (first element).
+  for (let i = subgraphLineage.length - 1; i > 1; i--) {
+    const graft = subgraphLineage[i]
+
+    // Block height is stored in the previous element in the lineage list.
+    // Since we are skipping the root (last element), the graft info is expected to be present.
+    const desiredBlockHeight = subgraphLineage[i - 1].graft!.block
+
+    if (!graft.indexingStatus || !graft.indexingStatus.latestBlock) {
+      // Graph Node is not aware of this subgraph deployment. We must deploy it and look no further.
+      deploymentDecisions.push({
+        deployment: graft.deployment,
+        deploymentDecision: SubgraphDeploymentDecisionKind.DEPLOY,
+      })
+      break
+    } else {
+      // Deployment exists.
+
+      // Is it sufficiently synced?
+      if (graft.indexingStatus.latestBlock.number >= desiredBlockHeight) {
+        // If so, we can stop syncing it.
+        deploymentDecisions.push({
+          deployment: graft.deployment,
+          deploymentDecision: SubgraphDeploymentDecisionKind.REMOVE,
+        })
+        continue
+      }
+
+      // Is it healthy?
+      if (graft.indexingStatus.health !== 'healthy') {
+        throw new Error(`Unhealthy graft base: ${graft.deployment}`)
+      }
+    }
+  }
+  return deploymentDecisions
+}
diff --git a/packages/indexer-common/src/types.ts b/packages/indexer-common/src/types.ts
index c0885a60d..d5896f05b 100644
--- a/packages/indexer-common/src/types.ts
+++ b/packages/indexer-common/src/types.ts
@@ -120,3 +120,15 @@ export const SubgraphManifestSchema = z.object({
 })
 
 export type SubgraphManifest = z.infer<typeof SubgraphManifestSchema>
+
+export enum SubgraphDeploymentDecisionKind {
+  CREATE = 'create',
+  DEPLOY = 'deploy',
+  REMOVE = 'remove',
+  // Possible new members: PAUSE, DROP, NOOP
+}
+
+export interface SubgraphDeploymentDecision {
+  deployment: SubgraphDeploymentID
+  deploymentDecision: SubgraphDeploymentDecisionKind
+}