Step Functions: Update map run from the CLI

Part 392 of AWS from Zero. This is lesson 11 in the Step Functions track.

What we are learning

Use update-map-run to change one Step Functions configuration deliberately and inspect the resulting state. This lesson identifies the required input shape, saves the raw response, and keeps inspection separate from execution.

The AWS CLI operation is aws stepfunctions update-map-run. Required operation inputs: --map-run-arn (string). The modeled top-level response contains no modeled response body.

Before you run it

aws sts get-caller-identity
REGION="${AWS_REGION:-ap-south-1}"
MAP_RUN_ARN="replace-with-map-run-arn"
aws stepfunctions update-map-run help

Use a sandbox account or an approved learning environment. Read the operation help before supplying identifiers, ARNs, network ranges, policy documents, or customer data.

Cost note: State transitions or Express workflow requests and duration can incur charges.

The command

aws stepfunctions update-map-run \
  --map-run-arn "$MAP_RUN_ARN" \
  --region "$REGION" \
  --output json > part-392-response.json

The response is saved to part-392-response.json so inspection is separate from execution. The explicit variables above keep required identifiers visible before the API call.

Inspect the result

# A zero-byte response can be normal for operations without a response body.
wc -c part-392-response.json
aws stepfunctions help

Compare the returned identifiers and status fields with the account, Region, and resource you intended to target. For asynchronous operations, continue with the service's matching get, list, or describe command until it reaches a terminal state.

One tiny variation

test -s part-392-response.json \
  && node -e "console.log(require('./part-392-response.json'))" \
  || echo "The operation returned no response document."

This variation changes output inspection rather than adding another infrastructure concept. Keep the raw JSON while developing a query so a narrow projection does not hide an error or unexpected field.

Common mistake

Do not treat a zero exit code as proof that the intended state is active everywhere. AWS control planes can be eventually consistent, and some operations start asynchronous work.

Cleanup

# This operation is read-only, operational, or needs resource-specific rollback.
# Re-read the command output before changing shared infrastructure.
rm -f part-392-request.json part-392-response.json part-392-payload.bin part-392-debug.log

Local request and response files may contain account IDs, ARNs, names, or service configuration. Remove them when the lab is complete and follow dependency-aware cleanup for any AWS resource you created.

Next, we will learn Step Functions: Update state machine from the CLI.

Official AWS CLI reference