Merge pull request #170 from overmindtech/164-fail-with-a-nice-error-…

…when-pointed-at-a-statefile

164 fail with a nice error when pointed at a statefile

.github/workflows/release.yml

@@ -12,9 +12,6 @@ jobs:
       contents: write
       packages: write
 
-    env:
-      GOEXPERIMENT: loopvar
-
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.github/workflows/tests.yml

@@ -6,7 +6,6 @@ jobs:
     runs-on: ubuntu-latest
     env:
       CGO_ENABLED: 0
-      GOEXPERIMENT: loopvar
 
     steps:
       - name: Checkout
@@ -29,8 +28,6 @@ jobs:
   golangci:
     name: lint
     runs-on: ubuntu-latest
-    env:
-      GOEXPERIMENT: loopvar
 
     steps:
       - name: Checkout

cmd/submitplan.go

@@ -281,6 +281,25 @@ func (g *plannedChangeGroups) Add(typ string, item *sdp.MappedItemDiff) {
 	groups[typ] = append(list, item)
 }
 
+// Checks if the supplied JSON bytes are a state file. It's a common  mistake to
+// pass a state file to Overmind rather than a plan file since the commands to
+// create them are similar
+func isStateFile(bytes []byte) bool {
+	fields := make(map[string]interface{})
+
+	err := json.Unmarshal(bytes, &fields)
+
+	if err != nil {
+		return false
+	}
+
+	if _, exists := fields["values"]; exists {
+		return true
+	}
+
+	return false
+}
+
 func mappedItemDiffsFromPlan(ctx context.Context, fileName string, lf log.Fields) ([]*sdp.MappedItemDiff, error) {
 	// read results from `terraform show -json ${tfplan file}`
 	planJSON, err := os.ReadFile(fileName)
@@ -289,6 +308,11 @@ func mappedItemDiffsFromPlan(ctx context.Context, fileName string, lf log.Fields
 		return nil, err
 	}
 
+	// Check that we haven't been passed a state file
+	if isStateFile(planJSON) {
+		return nil, fmt.Errorf("'%v' appears to be a state file, not a plan file", fileName)
+	}
+
 	var plan Plan
 	err = json.Unmarshal(planJSON, &plan)
 	if err != nil {

cmd/submitplan_test.go

@@ -9,6 +9,14 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func TestWithStateFile(t *testing.T) {
+	_, err := mappedItemDiffsFromPlan(context.Background(), "testdata/state.json", logrus.Fields{})
+
+	if err == nil {
+		t.Error("Expected error when running with state file, got none")
+	}
+}
+
 func TestMappedItemDiffsFromPlan(t *testing.T) {
 	mappedItemDiffs, err := mappedItemDiffsFromPlan(context.Background(), "testdata/plan.json", logrus.Fields{})
 

cmd/testdata/state.json

@@ -0,0 +1,11 @@
+{
+    "format_version": "1.0",
+    "terraform_version": "1.5.7",
+    "values": {
+        "outputs": {},
+        "root_module": {
+            "resources": [],
+            "child_modules": []
+        }
+    }
+}