Merge pull request #78 from cloudskiff/driftignore_field_case_insensitive

Make driftignore fields case-insensitive

Author: eliecharra

doc/cmd/scan/filter.md

@@ -18,12 +18,14 @@ Create the .driftignore file where you launch driftctl (usually the root of your
 
 Each line must be of kind
 - `resource_type.resource_id`, resource_id could be a wildcard to exclude all resources of a given type.
-- `resource_type.resource_id.path.to.field`, resource_id can be wildcard to ignore a drift on given field for a given type, path could also contain wildcards.
+- `resource_type.resource_id.path.to.FieldName`, resource_id can be wildcard to ignore a drift on given field for a given type, path could also contain wildcards.
+
+**N.B.** Fields are not case-sensitive.
 
 If your resource id or the path of a field contains dot or backslash you can escape them with backslashes:
 ```ignore
-resource_type.resource\.id\.containing\.dots.path.to.dotted\.fieldname
-resource_type.resource_id_containing\\backslash.path.to.backslash\\fieldname
+resource_type.resource\.id\.containing\.dots.path.to.dotted\.FieldName
+resource_type.resource_id_containing\\backslash.path.to.backslash\\FieldName
 ```
 
 ### Example
@@ -34,9 +36,9 @@ aws_s3_bucket.my-buckey
 # Will ignore every aws_instance resource
 aws_instance.*
 # Will ignore environement for all lambda functions
-aws_lambda_function.*.environment
+aws_lambda_function.*.Environment
 # Will ignore lastModified for my-lambda-name lambda function
-aws_lambda_function.my-lambda-name.lastmodified
+aws_lambda_function.my-lambda-name.LastModified
 ```
 
 ## Filter rules

pkg/filter/driftignore.go

@@ -112,7 +112,7 @@ RuleCheck:
 		}
 
 		for i := range path {
-			if path[i] != strings.ToLower(changePath[i]) && path[i] != "*" {
+			if !strings.EqualFold(path[i], changePath[i]) && path[i] != "*" {
 				continue RuleCheck // found a diff in path that was not a wildcard
 			}
 		}

pkg/filter/testdata/drift_ignore_fields/.driftignore

@@ -1,8 +1,8 @@
-res_type.full_drift_ignored.json
+res_type.full_drift_ignored.Json
 res_type.full_drift_ignored.foobar
-res_type.partial_drift_ignored.foobar
-res_type.wildcard_drift_ignored.*.baz
-res_type.endofpath_drift_ignored.struct
-resource_type.id\.with\.dots.json
-resource_type.idwith\\.json
-resource_type.idwith\\backslashes.foobar
+res_type.partial_drift_ignored.Foobar
+res_type.wildcard_drift_ignored.*.Baz
+res_type.endofpath_drift_ignored.Struct
+resource_type.id\.with\.dots.Json
+resource_type.idwith\\.Json
+resource_type.idwith\\backslashes.Foobar