Mechanic is the one-tool-does-it-all automation app for Shopify. :)
Useful for multiple price points, or for offering customizations of the same item, this task lets you offer multiple variant listings for what is ultimately the same stock. A purchase of a particular variant results in the inventory for all other variants, for the same product, being lowered by the amount ordered.
Runs when a user triggers the task and every 10 minutes. Configuration includes product types to monitor.
Mechanic is designed to benefit everybody: merchants, customers, developers, agencies, Gurus, everybody.
That’s why we make it easy to configure automation without code, why we make it easy to tweak the underlying code once tasks are installed, and why we publish it all here for everyone to learn from.
{% assign search_query_parts = array %}
{% for product_type in options.product_types_to_monitor__array_required %}
{% assign search_query_parts[search_query_parts.size] = "product_type:" | append: product_type %}
{% endfor %}
{% assign search_query = search_query_parts | join: " OR " %}
{% if event.preview %}
{% capture variants_query %}
{
productVariants(
first: 250
query: {{ search_query | json }}
) {
pageInfo {
hasNextPage
}
edges {
node {
id
inventoryQuantity
inventoryItem {
id
}
product {
id
}
}
cursor
}
}
}
{% endcapture %}
{% assign variants_query_result = variants_query | shopify %}
{% action "cache" %}
{"set": {"key": "inventory_by_product:gid://shopify/Product/1234567890", "value": 500}}
{% endaction %}
{% capture primary_location_query %}
{
location {
id
}
}
{% endcapture %}
{% assign primary_location_query_result = primary_location_query | shopify %}
{% capture adjustment_query %}
mutation {
inventoryBulkAdjustQuantityAtLocation(
inventoryItemAdjustments: []
locationId: "gid://shopify/Location/123467890"
) {
inventoryLevels {
id
}
userErrors {
field
message
}
}
}
{% endcapture %}
{% action "shopify" adjustment_query %}
{% else %}
{% assign variants_by_product = hash %}
{% assign cursor = nil %}
{% for n in (0..100) %}
{% capture variant_query %}
{
productVariants(
first: 250
query: {{ search_query | json }}
after: {{ cursor | json }}
) {
pageInfo {
hasNextPage
}
edges {
node {
id
inventoryQuantity
inventoryItem {
id
}
product {
id
}
}
cursor
}
}
}
{% endcapture %}
{% assign variant_query_result = variant_query | shopify %}
{% assign variant_nodes = variant_query_result.data.productVariants.edges | map: "node" %}
{% for variant_node in variant_nodes %}
{% assign product_id = variant_node.product.id %}
{% if variants_by_product[product_id] == nil %}
{% assign variants_by_product[product_id] = array %}
{% endif %}
{% assign index = variants_by_product[product_id].size %}
{% assign variants_by_product[product_id][index] = variant_node %}
{% endfor %}
{% if variant_query_result.data.productVariants.pageInfo.hasNextPage %}
{% assign cursor = variant_query_result.data.productVariants.edges.last.cursor %}
{% continue %}
{% endif %}
{% break %}
{% endfor %}
{% if event.topic == "mechanic/user/trigger" %}
{% for pair in variants_by_product %}
{% assign product_id = pair[0] %}
{% assign variants = pair[1] %}
{% assign unique_inventory_levels = variants | map: "inventoryQuantity" | uniq %}
{% if unique_inventory_levels.size != 1 %}
{"error": {{ "Ensure all products have even inventory levels across their variants, then try again. (Encountered mismatching inventory quantity in " | append: product_id | append: ")" | json }}}
{% break %}
{% else %}
{% assign cache_key = "inventory_by_product:" | append: product_id %}
{% action "cache" %}
{"set": {"key": {{ cache_key | json }}, "value": {{ variants.first.inventoryQuantity | json }}}}
{% endaction %}
{% endif %}
{% endfor %}
{% elsif event.topic contains "mechanic/scheduler/" %}
{% assign inventory_item_adjustments = array %}
{% capture primary_location_query %}
{
location {
id
}
}
{% endcapture %}
{% assign primary_location_query_result = primary_location_query | shopify %}
{% assign primary_location_id = primary_location_query_result.data.location.id %}
{% for pair in variants_by_product %}
{% assign product_id = pair[0] %}
{% assign variants = pair[1] %}
{% assign cache_key = "inventory_by_product:" | append: product_id %}
{% assign starting_inventory = cache[cache_key] %}
{% assign inventory_list = variants | map: "inventoryQuantity" %}
{% assign inventory_total = inventory_list | sum %}
{% assign inventory_diff = starting_inventory | times: inventory_list.size | minus: inventory_total %}
{% assign new_inventory = starting_inventory | minus: inventory_diff %}
{% if new_inventory == starting_inventory %}
{"log": {{ product_id | append: ": No inventory adjustments needed." | json }}}
{% else %}
{% action "cache" %}
{"set": {"key": {{ cache_key | json }}, "value": {{ new_inventory | json }}}}
{% endaction %}
{% for variant in variants %}
{% assign adjustment = hash %}
{% assign adjustment["inventoryItemId"] = variant.inventoryItem.id %}
{% assign adjustment["availableDelta"] = new_inventory | minus: variant.inventoryQuantity %}
{% assign inventory_item_adjustments[inventory_item_adjustments.size] = adjustment %}
{% endfor %}
{% endif %}
{% endfor %}
{% if inventory_item_adjustments.size > 0 %}
{% capture adjustment_query %}
mutation {
inventoryBulkAdjustQuantityAtLocation(
inventoryItemAdjustments: {{ inventory_item_adjustments | json | replace: '"inventoryItemId"', "inventoryItemId" | replace: '"availableDelta"', "availableDelta" }}
locationId: {{ primary_location_id | json }}
) {
inventoryLevels {
id
}
userErrors {
field
message
}
}
}
{% endcapture %}
{% action "shopify" adjustment_query %}
{% endif %}
{% endif %}
{% endif %}["Shirt"]