ensure setup-cluster.sh creates unique atlas clusters(#346)

.evergreen/atlas/setup-atlas-cluster.sh

@@ -25,6 +25,7 @@ DRIVERS_ATLAS_GROUP_ID
 DRIVERS_ATLAS_LAMBDA_USER
 DRIVERS_ATLAS_LAMBDA_PASSWORD
 LAMBDA_STACK_NAME
+task_id
 )
 
 # Ensure that all variables required to run the test are set, otherwise throw

.evergreen/atlas/setup-variables.sh

@@ -9,6 +9,8 @@ set -o errexit # Exit the script with error if any of the commands fail
 #
 # FUNCTION_NAME: Uses the stack name plus the current commit sha to create a unique cluster and function.
 # ATLAS_BASE_URL: Where the Atlas API root resides.
+# task_id: The `task_id` evergreen expansion associated with the CI run (or a unique identifier with which to create the function name).
+# Note: This MUST be unique per-CI task. Otherwise, multiple tasks calling this script may attempt to create clusters with the same name.
 
 
 # The Atlas API version
@@ -17,5 +19,8 @@ ATLAS_API_VERSION="v1.0"
 # support testing cluster outages.
 ATLAS_BASE_URL="https://cloud.mongodb.com/api/atlas/$ATLAS_API_VERSION"
 
+# create a unique per CI task tag for the function.
+TASK_NAME=$(echo $task_id | base64 | head -c 8)
+
 # Add git commit to name of function and cluster.
-FUNCTION_NAME="${LAMBDA_STACK_NAME}-$(git rev-parse --short HEAD)"
+FUNCTION_NAME="${LAMBDA_STACK_NAME}-${TASK_NAME}-$(git rev-parse --short HEAD)"

.evergreen/atlas/teardown-atlas-cluster.sh

@@ -18,6 +18,7 @@ DRIVERS_ATLAS_PUBLIC_API_KEY
 DRIVERS_ATLAS_PRIVATE_API_KEY
 DRIVERS_ATLAS_GROUP_ID
 LAMBDA_STACK_NAME
+task_id
 )
 
 # Ensure that all variables required to run the test are set, otherwise throw