Function states and invocation for custom images - Function Compute

Custom Container functions depend on resources that Function Compute reserves on your behalf, including images cached from Alibaba Cloud Container Registry (ACR) to reduce cold start latency. Because image caching happens asynchronously in the background, a function may not be ready to handle invocations immediately after it is created or updated. Function states tell you exactly when a function is ready to invoke.

Function states

Function Compute assigns every Custom Container function one of the following states.

State	Invocable	Description
Pending	No	The initial state after a function is created. Function Compute is reserving resources and caching the image. Transitions to Active when the image is ready.
Active	Yes	Resource reservation is complete. The function handles invocations normally.
Failed	No	Resource preparation or image access encountered an error. See Failed state for recovery steps.
Inactive	No	The function was idle long enough for Function Compute to release its cached resources. Redeploy or trigger the function to return it to Pending. If resource preparation succeeds, the function returns to Active; otherwise, it remains Inactive.

Failed state

A function enters the Failed state in two situations:

Resource preparation failed during creation or update: The function cannot be invoked because an issue occurred during resource preparation.
Original image is no longer accessible: Function Compute caches images to speed up cold starts, but the original image in ACR must remain accessible during invocations. If the image is deleted or the tag is overwritten with a different digest, the function enters the Failed state. Update the function with valid image information and redeploy.

Important

Function Compute records both the tag and the digest of the image version you select when you create or update a function. If that digest is later overwritten in ACR, the function fails to invoke. Make sure image tags are not overwritten after deployment. If overwritten, redeploy the function using the most recent image information.

Update states

While a function update is in progress, the LastUpdateStatus field tracks the update separately from the function's main state.

`LastUpdateStatus`	Description	Invocation routing
`InProgress`	Function Compute is preparing resources for the update.	Directed to the pre-update code
`Successful`	The update completed.	Directed to the updated code
`Failed`	Resource preparation for the update failed.	Directed to the pre-update code

Check state before invoking

You can call the GetFunction operation to obtain the state and image digest of a function. If you use an SDK or Serverless Devs to create or update a Custom Container function, call the GetFunction operation to verify the function state before invoking.

Newly created functions: confirm the state is Active. Functions in other states cannot be invoked.
Updated functions: confirm LastUpdateStatus is Successful.

State diagrams

The following output shows the s3 info result for a newly created function in the Pending state (Function Compute is reserving resources and caching the image).

s3 info

Steps for [info] of [hello-world-app]
====================
✔ [hello_world] completed (3.68s)

Result for [info] of [hello-world-app]
====================
hello_world:
  region:               us-east-1
  codeChecksum:
  codeSize:             0
  cpu:                  0.5
  createdTime:          2023-10-27T06:56:00Z
  customContainerConfig:
    image:              registry.us-east-1.aliyuncs.com/fxxx2/flask_xxx_ask_v001
    resolvedImageUri:   registry.us-east-1.aliyuncs.com/fc-dxxx_ask@shaxxx9e19867xxx23c4xxx78ffxxx4116cd9xxx9cde7370b43dd889
  description:          hello world by serverless devs
  diskSize:             512
  functionArn:          acs:fc:us-east-1:143*********149:functions/start-python-xxx:3
  functionId:           b24c69ed-0xxx-xxx-5ff3f51c4190
  functionName:         start-pxxx_xilixxx_est3
  handler:              handler
  instanceConcurrency:  1
  internetAccess:       true
  lastModifiedTime:     2023-10-27T06:56:00Z
  memorySize:           512
  role:
  runtime:              custom-container
  state:                Pending
  stateReason:          The function is being created.
  stateReasonCode:      Creating
  timeout:              60

A complete log of this run can be found in: /home/admin/.s/logs/1027145606

The following output shows the s3 info result for a function being updated (LastUpdateStatus: InProgress).

admin  ~/workspace/xxx/demo-3  s3 info
  Steps for [ixxx-app]
========================

✔ [hello_world] completed (4.97s)

Result for [info] of [hello-world-app]
========================
hello_world:
  region:               us-east-1
  codeChecksum:
  codeSize:             0
  cpu:                  0.5
  createdTime:          2023-10-27T05:45:30Z
  customContainerConfig:
    image:              registry.us-east-1.aliyuncs.comxxx k:f   k_vxxx
    resolvedImageUri: registry.us-east-1.aliyuncs.com/fcxxx k@sha256:f65d0acd5xxx ab9cd923f3afxxx b9exxx 2cdxxx 99d51bbae2fe0ba
  description:          hello world by serverless devs
  diskSize:             512
  functionArn:          acs:fc:us-east-1:143**********149:functions/start-pxxx xilxxx
  functionId:           82597d19xxx f-9581fe2429d7
  functionName:         start-pythonxxx t1
  handler:              handler
  instanceConcurrency:  1
  internetAccess:       true
  lastModifiedTime:     2023-10-27T06:52:03Z
  lastUpdateStatus:     InProgress
  memorySize:           512
  role:
  runtime:              custom-container
  state:                Active
  timeout:              60

A complete log of this run can be found in: /home/admin/.s/logs/xxx5200

The following output shows the s3 info result after a successful update. When lastUpdateStatus is Successful and state is Active, the function update has completed and the function is in the active state.

admin  ~/wc       xxx       mo-3    s3 info
Steps for [info] of [hello-world-app]
====================
✔ [hello_world] completed (1.32s)

Result for [info] of [hello-world-app]
====================
hello_world:
  region:               us-east-1
  codeChecksum:
  codeSize:             0
  cpu:                  0.5
  createdTime:          2023-10-27T05:45:30Z
  customContainerConfig:
    image:              registry.us-east-1.aliyuncs.com,xxx/flask:flask_v001
    resolvedImageUri:   registry.us-east-1.aliyuncs.com,xxx/mo2/flask@sha256:9614366c50xxx4bcxxxxxxxxxxxxxxxx/cae95c74f44
  description:          hello world by serverless dexxx
  diskSize:             512
  functionArn:          acs:fc:us-east-1:xxx:49:functions/start-pyxxxxxxxx
  functionId:           82597d19-2bc0-41c3-92f1-xxx429d7
  functionName:         start-pyxxx-n-xxxxxx1
  handler:              handler
  instanceConcurrency:  1
  internetAccess:       true
  lastModifiedTime:     2023-10-27T05:56:10Z
  lastUpdateStatus:     Successful
  logConfig:
    enableInstanceMetrics: true
    enableRequestMetrics:  true
    logBeginRule:       DefaultRegex
    logstore:           function-log
    project:            aliyun-fc xxx0908f0a5f
  memorySize:           512
  role:
  runtime:              custom-container
  state:                Active
  timeout:              60

A complete log of this run can be found in: /home/admin/.s/logs/xxx