Example on how to fetch all the functions resolver for an GraphQL API on AWS and output them per template (dealing with VTL)

get_resolvers.sh

#!/bin/sh

# set the table list for "DrawTable" "GameTable" "PlayroundTable"
TABLE_NAMES="DrawTable GameTable PlayroundTable"
# API_ID="asdasdadajsdljalskdjalksdj"
# use the following command to get the list of functions
# FUNCTION_FILE=$(aws appsync list-functions --api-id "$API_ID")
FUNCTION_FILE="list_functions_full.json"

rm -rf resolvers
mkdir -p resolvers

COUNT=0

# loop through the tables
for TABLE_NAME in $TABLE_NAMES
  # print the table name
  do printf "\nFinding all functions for %s table.\n" "$TABLE_NAME"

  # use jq to find all the function names that use the table and store them in a variable
  FUNCTION_NAMES=$(jq -r --arg TABLE_NAME "$TABLE_NAME" '.functions[] | select(.dataSourceName == $TABLE_NAME) | .name' $FUNCTION_FILE | sort | uniq)

  # loop through the functions
  for FUNCTION_NAME in $FUNCTION_NAMES
    do

    # define ignore list
    IGNORE_LIST="auth0"

    # check if the function name contains any of the terms in the ignore list
    if [[ "$FUNCTION_NAME" == *"$IGNORE_LIST"* ]]; then
      # if it does, skip it
      echo "  > Skipping $FUNCTION_NAME"
      continue
    fi

    # print the function name
    echo "  $FUNCTION_NAME"

    # rename the function name to be param case
    KEBAB_CASE=$(echo "$FUNCTION_NAME" | sed 's/\(.\)\([A-Z]\)/\1-\2/g' | tr '[:upper:]' '[:lower:]')
    # remove substring: "data-resolver-fn"
    CLEANED_NAME=$(echo "$KEBAB_CASE" | sed 's/data-resolver-fn-//')

    # for each function name extract the value for the following fields: requestMappingTemplate, responseMappingTemplate
    REQUEST_MAPPING_TEMPLATE=$(jq -r --arg FUNCTION_NAME "$FUNCTION_NAME" '.functions[] | select(.name == $FUNCTION_NAME) | .requestMappingTemplate' $FUNCTION_FILE)
    RESPONSE_MAPPING_TEMPLATE=$(jq -r --arg FUNCTION_NAME "$FUNCTION_NAME" '.functions[] | select(.name == $FUNCTION_NAME) | .responseMappingTemplate' $FUNCTION_FILE)

    mkdir -p "resolvers/$CLEANED_NAME"

    # Save those to 2 different files which names are the function names AND request or response
    echo "$REQUEST_MAPPING_TEMPLATE" > "resolvers/$CLEANED_NAME/request.vtl"
    echo "$RESPONSE_MAPPING_TEMPLATE" > "resolvers/$CLEANED_NAME/response.vtl"

    # increment the count by 2
    COUNT=$((COUNT+2))
  done

# end the loop
done

# print the count
printf "\nTotal number of files created: %d\n" "$COUNT"