[contracts] Make contract interactions optional in the node (#91)

Adds --eth-deployment parameter.
Does not crash when deployment json is missing or incorrect.

dagger/conf.nim

@@ -154,6 +154,12 @@ type
         name: "eth-account"
       .}: EthAddress
 
+      ethDeployment* {.
+        desc: "The json file describing the contract deployment"
+        defaultValue: string.default
+        name: "eth-deployment"
+      .}: string
+
     of initNode:
       discard
 

dagger/contracts/deployment.nim

@@ -16,5 +16,11 @@ proc deployment*(file = defaultFile): Deployment =
   Deployment(json: parseFile(file))
 
 proc address*(deployment: Deployment, Contract: typedesc): ?Address =
-  let address = deployment.json["contracts"][$Contract]["address"].getStr()
+  if deployment.json == nil:
-  Address.init(address)
+    return none Address
+
+  try:
+    let address = deployment.json["contracts"][$Contract]["address"].getStr()
+    Address.init(address)
+  except KeyError:
+    none Address

dagger/contracts/interactions.nim

@@ -1,4 +1,5 @@
 import pkg/ethers
+import pkg/chronicles
 import ../purchasing
 import ../sales
 import ../proving
@@ -10,6 +11,7 @@ import ./proofs
 export purchasing
 export sales
 export proving
+export chronicles
 
 type
   ContractInteractions* = ref object
@@ -19,11 +21,16 @@ type
 
 proc new*(_: type ContractInteractions,
           signer: Signer,
-          deployment: Deployment): ContractInteractions =
+          deployment: Deployment): ?ContractInteractions =
-  let contract = Storage.new(!deployment.address(Storage), signer)
+
+  without address =? deployment.address(Storage):
+    error "Unable to determine address of the Storage smart contract"
+    return none ContractInteractions
+
+  let contract = Storage.new(address, signer)
   let market = OnChainMarket.new(contract)
   let proofs = OnChainProofs.new(contract)
-  ContractInteractions(
+  some ContractInteractions(
     purchasing: Purchasing.new(market),
     sales: Sales.new(market),
     proving: Proving.new(proofs)
@@ -31,16 +38,30 @@ proc new*(_: type ContractInteractions,
 
 proc new*(_: type ContractInteractions,
           providerUrl: string,
-          account = Address.default): ContractInteractions =
+          deploymentFile: string = string.default,
+          account = Address.default): ?ContractInteractions =
+
   let provider = JsonRpcProvider.new(providerUrl)
+
   var signer: Signer
   if account == Address.default:
     signer = provider.getSigner()
   else:
     signer = provider.getSigner(account)
-  ContractInteractions.new(signer, deployment())
 
-proc new*(_: type ContractInteractions): ContractInteractions =
+  var deploy: Deployment
+  try:
+    if deploymentFile == string.default:
+      deploy = deployment()
+    else:
+      deploy = deployment(deploymentFile)
+  except IOError as e:
+    error "Unable to read deployment json", msg = e.msg
+    return none ContractInteractions
+
+  ContractInteractions.new(signer, deploy)
+
+proc new*(_: type ContractInteractions): ?ContractInteractions =
   ContractInteractions.new("ws://localhost:8545")
 
 proc start*(interactions: ContractInteractions) {.async.} =

dagger/dagger.nim

@@ -122,7 +122,11 @@ proc new*(T: type DaggerServer, config: DaggerConf): T =
     engine = BlockExcEngine.new(localStore, wallet, network, discovery)
     store = NetworkStore.new(engine, localStore)
     erasure = Erasure.new(store, leoEncoderProvider, leoDecoderProvider)
-    contracts = ContractInteractions.new(config.ethProvider, config.ethAccount)
+    contracts = ContractInteractions.new(
+      config.ethProvider,
+      config.ethDeployment,
+      config.ethAccount
+    )
     daggerNode = DaggerNodeRef.new(switch, store, engine, erasure, discovery, contracts)
     restServer = RestServerRef.new(
       daggerNode.initRestApi(),

dagger/node.nim

@@ -43,7 +43,7 @@ type
     engine*: BlockExcEngine
     erasure*: Erasure
     discovery*: Discovery
-    contracts*: ContractInteractions
+    contracts*: ?ContractInteractions
 
 proc start*(node: DaggerNodeRef) {.async.} =
   await node.switch.start()
@@ -51,8 +51,8 @@ proc start*(node: DaggerNodeRef) {.async.} =
   await node.erasure.start()
   await node.discovery.start()
 
-  if not node.contracts.isNil:
+  if contracts =? node.contracts:
-    await node.contracts.start()
+    await contracts.start()
 
   node.networkId = node.switch.peerInfo.peerId
   notice "Started dagger node", id = $node.networkId, addrs = node.switch.peerInfo.addrs
@@ -65,8 +65,8 @@ proc stop*(node: DaggerNodeRef) {.async.} =
   await node.erasure.stop()
   await node.discovery.stop()
 
-  if not node.contracts.isNil:
+  if contracts =? node.contracts:
-    await node.contracts.stop()
+    await contracts.stop()
 
 proc findPeer*(
   node: DaggerNodeRef,
@@ -244,7 +244,7 @@ proc new*(
   engine: BlockExcEngine,
   erasure: Erasure,
   discovery: Discovery,
-  contracts: ContractInteractions): T =
+  contracts: ?ContractInteractions): T =
   T(
     switch: switch,
     blockStore: store,

tests/contracts/testInteractions.nim

@@ -1,3 +1,4 @@
+import std/os
 import ./ethertest
 import dagger/contracts
 import ./examples
@@ -7,18 +8,20 @@ ethersuite "Storage Contract Interactions":
   var contracts: ContractInteractions
 
   setup:
-    contracts = ContractInteractions.new()
+    contracts = !ContractInteractions.new()
 
   test "can be instantiated with a signer and deployment info":
     let signer = provider.getSigner()
     let deployment = deployment()
-    check ContractInteractions.new(signer, deployment) != nil
+    check ContractInteractions.new(signer, deployment).isSome
 
   test "can be instantiated with a provider url and account":
     let url = "http://localhost:8545"
     let account = Address.example
-    check ContractInteractions.new(url) != nil
+    let deployment = "vendor" / "dagger-contracts" / "deployment-localhost.json"
-    check ContractInteractions.new(url, account) != nil
+    check ContractInteractions.new(url).isSome
+    check ContractInteractions.new(url, account = account).isSome
+    check ContractInteractions.new(url, deploymentFile = deployment).isSome
 
   test "provides purchasing":
     check contracts.purchasing != nil

tests/dagger/testnode.nim

@@ -36,7 +36,7 @@ suite "Test Node":
     store: NetworkStore
     node: DaggerNodeRef
     discovery: Discovery
-    contracts: ContractInteractions
+    contracts: ?ContractInteractions
 
   setup:
     file = open(path.splitFile().dir /../ "fixtures" / "test.jpg")