Assets

You can discover, download, and share assets using Bonsai, the Sensu asset index. Read Install plugins with assets to get started.

Assets are shareable, reusable packages that make it easier to deploy Sensu plugins. You can use assets to provide the plugins, libraries, and runtimes you need to automate your monitoring workflows. Sensu supports runtime assets for checks, filters, mutators, and handlers.

NOTE: Assets are not required to use Sensu Go in production. You can install Sensu plugins using the sensu-install tool or a configuration management solution.

The Sensu backend executes handler, filter, and mutator assets. The Sensu agent executes check assets. At runtime, the backend or agent sequentially evaluates assets that appear in the runtime_assets attribute of the handler, filter, mutator, or check being executed.

Asset builds

An asset build is the combination of an artifact URL, SHA512 checksum, and optional Sensu query expression filters. Each asset definition may describe one or more builds.

NOTE: Assets that provide url and sha512 attributes at the top level of the spec scope are single-build assets, and this form of asset defintion is deprecated. We recommend using multiple-build asset defintions, which specify one or more builds under the spec scope.

Asset build evaluation

For each build provided in an asset, Sensu will evaluate any defined filters to determine whether any build matches the agent or backend service’s environment. If all filters specified on a build evaluate to true, that build is considered a match. For assets with multiple builds, only the first build which matches will be downloaded and installed.

Asset build installation

When Sensu finds a matching build, it downloads the build artifact from the specified URL. If the asset definition includes headers, they are passed along as part of the HTTP request. If the downloaded artifact’s SHA512 checksum matches the checksum provided by the build, it is unpacked into the Sensu service’s local cache directory.

Set the backend or agent’s local cache path with the --cache-dir flag. Disable assets for an agent with the agent --disable-assets configuration flag.

Asset build execution

The directory path of each asset defined in runtime_assets is appended to the PATH before the handler, filter, mutator, or check command is executed. Subsequent handler, filter, mutator, or check executions look for the asset in the local cache and ensure that the contents match the configured checksum.

See the example asset with a check for a use case with a Sensu resource (a check) and an asset.

Asset format specification

Sensu expects an asset to be a tar archive (optionally gzipped) that contains one or more executables within a bin folder. Any scripts or executables should be within a bin/ folder in the archive. See the Sensu Go Plugin template for an example asset and Bonsai configuration.

The following are injected into the execution context:

  • {PATH_TO_ASSET}/bin is injected into the PATH environment variable
  • {PATH_TO_ASSET}/lib is injected into the LD_LIBRARY_PATH environment variable
  • {PATH_TO_ASSET}/include is injected into the CPATH environment variable

NOTE: You cannot create an asset by creating an archive of an existing project (as in previous versions of Sensu for plugins from the Sensu Plugins community). Follow the steps outlined in Contributing Assets for Existing Ruby Sensu Plugins, a Sensu Discourse guide. For further examples of Sensu users who have added the ability to use a community plugin as an asset, see this Discourse post.

Default cache directory

system sensu-backend sensu-agent
Linux /var/cache/sensu/sensu-backend /var/cache/sensu/sensu-agent
Windows N/A C:\ProgramData\sensu\cache\sensu-agent

If the requested asset is not in the local cache, it is downloaded from the asset URL. The Sensu backend does not currently provide any storage for assets. Sensu expects assets to be retrieved over HTTP or HTTPS.

Example asset structure

sensu-example-handler_1.0.0_linux_amd64
├── CHANGELOG.md
├── LICENSE
├── README.md
└── bin
  └── my-check.sh
└── lib
└── include

Asset hello world example

In this example, you’ll run a script that outputs Hello World:

hello-world.sh

#!/bin/sh

STRING="Hello World"

echo $STRING

if [ $? -eq 0 ]; then
    exit 0
else
    exit 2
fi

The first step is to ensure that your directory structure is in place. As noted in Example asset structure, your script could live in three potential directories in the project: /bin, /lib, or /include. For this example, put your script in the /bin directory. Create the directories sensu-go-hello-world and /bin:

$ mkdir sensu-go-hello-world

$ cd sensu-go-hello-world

$ mkdir bin

$ cp hello-world.sh bin/

$ tree
.
└── bin
    └── hello-world.sh

Next, make sure that the script is marked as executable:

$ chmod +x bin/hello-world.sh 
mode of 'hello-world.sh' changed from 0644 (rw-r--r--) to 0755 (rwxr-xr-x)

Now that the script is in the directory, move on to the next step: packaging the sensu-go-hello-world directory as an asset tarball.

Package the asset

Assets are archives, so the first step in packaging the asset is to create a tar.gz archive of your project. This assumes you’re in the directory you want to tar up:

$ cd ..
$ tar -C sensu-go-hello-world -cvzf sensu-go-hello-world-0.0.1.tar.gz .
...

Now that you’ve created an archive, you need to generate a SHA512 sum for it (this is required for the asset to work):

sha512sum sensu-go-hello-world-0.0.1.tar.gz | tee sha512sum.txt
dbfd4a714c0c51c57f77daeb62f4a21141665ae71440951399be2d899bf44b3634dad2e6f2516fff1ef4b154c198b9c7cdfe1e8867788c820db7bb5bcad83827 sensu-go-hello-world-0.0.1.tar.gz

From here, you can host your asset wherever you’d like. To make the asset available via Bonsai, you’ll need to host it on Github. Learn more in The “Hello World” of Sensu Assets on Discourse.

To host your asset on a different platform like Gitlab or Bitbucket, upload your asset there. You can also use Artifactory or even Apache or Nginx to serve your asset. All that’s required for your asset to work is the URL to the asset and the SHA512 sum for the asset to be downloaded.

Asset specification

Top-level attributes

type
description Top-level attribute that specifies the sensuctl create resource type. Assets should always be type Asset.
required Required for asset definitions in wrapped-json or yaml format for use with sensuctl create.
type String
example
"type": "Asset"
api_version
description Top-level attribute that specifies the Sensu API group and version. For assets in this version of Sensu, the api_version should always be core/v2.
required Required for asset definitions in wrapped-json or yaml format for use with sensuctl create.
type String
example
"api_version": "core/v2"
metadata
description Top-level collection of metadata about the asset, including name, namespace, and created_by as well as custom labels and annotations. The metadata map is always at the top level of the asset definition. This means that in wrapped-json and yaml formats, the metadata scope occurs outside the spec scope. See metadata attributes for details.
required Required for asset definitions in wrapped-json or yaml format for use with sensuctl create.
type Map of key-value pairs
example
"metadata": {
  "name": "check_script",
  "namespace": "default",
  "created_by": "admin",
  "labels": {
    "region": "us-west-1"
  },
  "annotations": {
    "playbook" : "www.example.url"
  }
}
spec
description Top-level map that includes the asset spec attributes.
required Required for asset definitions in wrapped-json or yaml format for use with sensuctl create.
type Map of key-value pairs
example (multiple builds)
"spec": {
  "builds": [
    {
      "url": "http://example.com/asset-linux-amd64.tar.gz",
      "sha512": "487ab34b37da8ce76d2657b62d37b35fbbb240c3546dd463fa0c37dc58a72b786ef0ca396a0a12c8d006ac7fa21923e0e9ae63419a4d56aec41fccb574c1a5d3",
      "filters": [
        "entity.system.os == 'linux'",
        "entity.system.arch == 'amd64'"
      ]
    },
    {
        "url": "http://example.com/asset-linux-armv7.tar.gz",
        "sha512": "70df8b7e9aa36cf942b972e1781af04815fa560441fcdea1d1538374066a4603fc5566737bfd6c7ffa18314edb858a9f93330a57d430deeb7fd6f75670a8c68b",
        "filters": [
          "entity.system.os == 'linux'",
          "entity.system.arch == 'arm'",
          "entity.system.arm_version == 7"
        ]
      }
  ],
  "headers": {
    "Authorization": "Bearer $TOKEN",
    "X-Forwarded-For": "client1, proxy1, proxy2"
  }
}
example (single build, deprecated)
"spec": {
  "url": "http://example.com/asset.tar.gz",
  "sha512": "4f926bf4328fbad2b9cac873d117f771914f4b837c9c85584c38ccf55a3ef3c2e8d154812246e5dda4a87450576b2c58ad9ab40c9e2edc31b288d066b195b21b",
  "filters": [
    "entity.system.os == 'linux'",
    "entity.system.arch == 'amd64'"
  ],
  "headers": {
    "Authorization": "Bearer $TOKEN",
    "X-Forwarded-For": "client1, proxy1, proxy2"
  }
}

Metadata attributes

name
description Unique name of the asset, validated with Go regex \A[\w\.\-]+\z.
required true
type String
example
"name": "check_script"
namespace
description Sensu RBAC namespace that the asset belongs to.
required false
type String
default default
example
"namespace": "production"
created_by
description Username of the Sensu user who created the asset or last updated the asset. Sensu automatically populates the created_by field when the asset is created or updated.
required false
type String
example
"created_by": "admin"
labels
description Custom attributes to include with event data that you can use for response and dashboard view filtering.

If you include labels in your event data, you can filter API responses, sensuctl responses, and dashboard views based on them. In other words, labels allow you to create meaningful groupings for your data.

Limit labels to metadata you need to use for response filtering. For complex, non-identifying metadata that you will not need to use in response filtering, use annotations rather than labels.
required false
type Map of key-value pairs. Keys can contain only letters, numbers, and underscores and must start with a letter. Values can be any valid UTF-8 string.
default null
example
"labels": {
  "environment": "development",
  "region": "us-west-2"
}
annotations
description Non-identifying metadata to include with event data that you can access with event filters. You can use annotations to add data that’s meaningful to people or external tools that interact with Sensu.

In contrast to labels, you cannot use annotations in API response filtering, sensuctl response filtering, or dashboard views.
required false
type Map of key-value pairs. Keys and values can be any valid UTF-8 string.
default null
example
 "annotations": {
  "managed-by": "ops",
  "playbook": "www.example.url"
}

Spec attributes

builds
description List of asset builds used to define multiple artifacts that provide the named asset.
required true, if url, sha512 and filters are not provided
type Array
example
"builds": [
    {
      "url": "http://example.com/asset-linux-amd64.tar.gz",
      "sha512": "487ab34b37da8ce76d2657b62d37b35fbbb240c3546dd463fa0c37dc58a72b786ef0ca396a0a12c8d006ac7fa21923e0e9ae63419a4d56aec41fccb574c1a5d3",
      "filters": [
        "entity.system.os == 'linux'",
        "entity.system.arch == 'amd64'"
      ]
    },
    {
        "url": "http://example.com/asset-linux-armv7.tar.gz",
        "sha512": "70df8b7e9aa36cf942b972e1781af04815fa560441fcdea1d1538374066a4603fc5566737bfd6c7ffa18314edb858a9f93330a57d430deeb7fd6f75670a8c68b",
        "filters": [
          "entity.system.os == 'linux'",
          "entity.system.arch == 'arm'",
          "entity.system.arm_version == 7"
        ]
      }
  ]
url
description URL location of the asset.
required true, unless builds are provided
type String
example
"url": "http://example.com/asset.tar.gz"
sha512
description Checksum of the asset.
required true, unless builds are provided
type String
example
"sha512": "4f926bf4328..."
filters
description Set of Sensu query expressions used to determine if the asset should be installed. If multiple expressions are included, each expression must return true for Sensu to install the asset.

Filters for check assets should match agent entity platforms. Filters for handler and filter assets should match your Sensu backend platform. You can create asset filter expressions using any supported entity system attributes, including os, arch, platform, and platform_family.

PRO TIP: Asset filters let you reuse checks across platforms safely. Assign assets for multiple platforms to a single check, and rely on asset filters to ensure that only the appropriate asset is installed on each agent.

required false
type Array
example
"filters": ["entity.system.os=='linux'", "entity.system.arch=='amd64'"] 
headers
description HTTP headers to apply to asset retrieval requests. You can use headers to access secured assets. For headers that require multiple values, separate the values with a comma.
required false
type Map of key-value string pairs
example
"headers": {
  "Authorization": "Bearer $TOKEN",
  "X-Forwarded-For": "client1, proxy1, proxy2"
}

Examples

Minimum required asset attributes

type: Asset
api_version: core/v2
metadata:
  name: check_script
  namespace: default
spec:
  builds:
  - sha512: 4f926bf4328fbad2b9cac873d117f771914f4b837c9c85584c38ccf55a3ef3c2e8d154812246e5dda4a87450576b2c58ad9ab40c9e2edc31b288d066b195b21b
    url: http://example.com/asset.tar.gz
{
  "type": "Asset",
  "api_version": "core/v2",
  "metadata": {
    "name": "check_script",
    "namespace": "default"
  },
  "spec": {
    "builds": [
      {
        "url": "http://example.com/asset.tar.gz",
        "sha512": "4f926bf4328fbad2b9cac873d117f771914f4b837c9c85584c38ccf55a3ef3c2e8d154812246e5dda4a87450576b2c58ad9ab40c9e2edc31b288d066b195b21b"
      }
    ]
  }
}

Asset definition (single-build, deprecated)

type: Asset
api_version: core/v2
metadata:
  name: check_cpu_linux_amd64
  namespace: default
  labels:
    origin: bonsai
  annotations:
    project_url: https://bonsai.sensu.io/assets/asachs01/sensu-go-cpu-check
    version: 0.0.3
spec:
  url: https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_linux_amd64.tar.gz
  sha512: 487ab34b37da8ce76d2657b62d37b35fbbb240c3546dd463fa0c37dc58a72b786ef0ca396a0a12c8d006ac7fa21923e0e9ae63419a4d56aec41fccb574c1a5d3
  filters:
  - entity.system.os == 'linux'
  - entity.system.arch == 'amd64'
  headers:
    Authorization: Bearer $TOKEN
    X-Forwarded-For: client1, proxy1, proxy2
{
  "type": "Asset",
  "api_version": "core/v2",
  "metadata": {
    "name": "check_cpu_linux_amd64",
    "namespace": "default",
    "labels": {
      "origin": "bonsai"
    },
    "annotations": {
      "project_url": "https://bonsai.sensu.io/assets/asachs01/sensu-go-cpu-check",
      "version": "0.0.3"
    }
  },
  "spec": {
    "url": "https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_linux_amd64.tar.gz",
    "sha512": "487ab34b37da8ce76d2657b62d37b35fbbb240c3546dd463fa0c37dc58a72b786ef0ca396a0a12c8d006ac7fa21923e0e9ae63419a4d56aec41fccb574c1a5d3",
    "filters": [
      "entity.system.os == 'linux'",
      "entity.system.arch == 'amd64'"
    ],
    "headers": {
      "Authorization": "Bearer $TOKEN",
      "X-Forwarded-For": "client1, proxy1, proxy2"
    }
  }
}

Asset definition (multiple-builds)

type: Asset
api_version: core/v2
metadata:
  name: check_cpu
  namespace: default
  labels:
    origin: bonsai
  annotations:
    project_url: https://bonsai.sensu.io/assets/asachs01/sensu-go-cpu-check
    version: 0.0.3
spec:
  builds:
  - url: https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_linux_amd64.tar.gz
    sha512: 487ab34b37da8ce76d2657b62d37b35fbbb240c3546dd463fa0c37dc58a72b786ef0ca396a0a12c8d006ac7fa21923e0e9ae63419a4d56aec41fccb574c1a5d3
    filters:
    - entity.system.os == 'linux'
    - entity.system.arch == 'amd64'
    headers:
      Authorization: Bearer $TOKEN
      X-Forwarded-For: client1, proxy1, proxy2
  - url: https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_linux_armv7.tar.gz
    sha512: 70df8b7e9aa36cf942b972e1781af04815fa560441fcdea1d1538374066a4603fc5566737bfd6c7ffa18314edb858a9f93330a57d430deeb7fd6f75670a8c68b
    filters:
    - entity.system.os == 'linux'
    - entity.system.arch == 'arm'
    - entity.system.arm_version == 7
    headers:
      Authorization: Bearer $TOKEN
      X-Forwarded-For: client1, proxy1, proxy2
  - url: https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_windows_amd64.tar.gz
    sha512: 10d6411e5c8bd61349897cf8868087189e9ba59c3c206257e1ebc1300706539cf37524ac976d0ed9c8099bdddc50efadacf4f3c89b04a1a8bf5db581f19c157f
    filters:
    - entity.system.os == 'windows'
    - entity.system.arch == 'amd64'
    headers:
      Authorization: Bearer $TOKEN
      X-Forwarded-For: client1, proxy1, proxy2
{
  "type": "Asset",
  "api_version": "core/v2",
  "metadata": {
    "name": "check_cpu",
    "namespace": "default",
    "labels": {
      "origin": "bonsai"
    },
    "annotations": {
      "project_url": "https://bonsai.sensu.io/assets/asachs01/sensu-go-cpu-check",
      "version": "0.0.3"
    }
  },
  "spec": {
    "builds": [
      {
        "url": "https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_linux_amd64.tar.gz",
        "sha512": "487ab34b37da8ce76d2657b62d37b35fbbb240c3546dd463fa0c37dc58a72b786ef0ca396a0a12c8d006ac7fa21923e0e9ae63419a4d56aec41fccb574c1a5d3",
        "filters": [
          "entity.system.os == 'linux'",
          "entity.system.arch == 'amd64'"
        ],
        "headers": {
          "Authorization": "Bearer $TOKEN",
          "X-Forwarded-For": "client1, proxy1, proxy2"
        }
      },
      {
        "url": "https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_linux_armv7.tar.gz",
        "sha512": "70df8b7e9aa36cf942b972e1781af04815fa560441fcdea1d1538374066a4603fc5566737bfd6c7ffa18314edb858a9f93330a57d430deeb7fd6f75670a8c68b",
        "filters": [
          "entity.system.os == 'linux'",
          "entity.system.arch == 'arm'",
          "entity.system.arm_version == 7"
        ],
        "headers": {
          "Authorization": "Bearer $TOKEN",
          "X-Forwarded-For": "client1, proxy1, proxy2"
        }
      },
      {
        "url": "https://assets.bonsai.sensu.io/981307deb10ebf1f1433a80da5504c3c53d5c44f/sensu-go-cpu-check_0.0.3_windows_amd64.tar.gz",
        "sha512": "10d6411e5c8bd61349897cf8868087189e9ba59c3c206257e1ebc1300706539cf37524ac976d0ed9c8099bdddc50efadacf4f3c89b04a1a8bf5db581f19c157f",
        "filters": [
          "entity.system.os == 'windows'",
          "entity.system.arch == 'amd64'"
        ],
        "headers": {
          "Authorization": "Bearer $TOKEN",
          "X-Forwarded-For": "client1, proxy1, proxy2"
        }
      }
    ]
  }
}

Example asset with a check

---
type: Asset
api_version: core/v2
metadata:
  name: sensu-prometheus-collector
  namespace: default
spec:
  builds:
  - url: https://assets.bonsai.sensu.io/ef812286f59de36a40e51178024b81c69666e1b7/sensu-prometheus-collector_1.1.6_linux_amd64.tar.gz
    sha512: a70056ca02662fbf2999460f6be93f174c7e09c5a8b12efc7cc42ce1ccb5570ee0f328a2dd8223f506df3b5972f7f521728f7bdd6abf9f6ca2234d690aeb3808
    filters:
    - entity.system.os == 'linux'
    - entity.system.arch == 'amd64'
---
type: CheckConfig
api_version: core/v2
metadata:
  name: prometheus_collector
  namespace: default
spec:
  command: "sensu-prometheus-collector -prom-url http://localhost:9090 -prom-query up"
  interval: 10
  publish: true
  output_metric_handlers:
  - influxdb
  output_metric_format: influxdb_line
  runtime_assets:
  - sensu-prometheus-collector
  subscriptions:
  - system
{
  "type": "Asset",
  "api_version": "core/v2",
  "metadata": {
    "name": "sensu-email-handler",
    "namespace": default
  },
  "spec": {
    "builds": [
      {
        "url": "https://assets.bonsai.sensu.io/45eaac0851501a19475a94016a4f8f9688a280f6/sensu-email-handler_0.2.0_linux_amd64.tar.gz",
        "sha512": "d69df76612b74acd64aef8eed2ae10d985f6073f9b014c8115b7896ed86786128c20249fd370f30672bf9a11b041a99adb05e3a23342d3ad80d0c346ec23a946",
        "filters": [
          "entity.system.os == 'linux'",
          "entity.system.arch == 'amd64'"
        ]
      }
    ]
  }
}
{
  "type": "CheckConfig",
  "api_version": "core/v2",
  "metadata": {
    "name": "prometheus_collector",
    "namespace": "default"
  },
  "spec": {
    "command": "sensu-prometheus-collector -prom-url http://localhost:9090 -prom-query up",
    "handlers": [
    "influxdb"
    ],
    "interval": 10,
    "publish": true,
    "output_metric_format": "influxdb_line",
    "runtime_assets": [
      "sensu-prometheus-collector"
    ],
    "subscriptions": [
      "system"
    ]
  }
}

Share an asset on Bonsai

Share your open-source assets on Bonsai and connect with the Sensu community. Bonsai supports assets hosted on GitHub and released using GitHub releases. For more information about creating Sensu Plugins, see the Sensu Plugin specification.

Bonsai requires a bonsai.yml configuration file in the root directory of your repository that includes the project description, platforms, asset filenames, and SHA-512 checksums. For a Bonsai-compatible asset template using Go and GoReleaser, see the Sensu Go plugin skeleton.

To share your asset on Bonsai, log in to Bonsai with your GitHub account and authorize Sensu. After you are logged in, you can register your asset on Bonsai by adding the GitHub repository, a description, and tags. Make sure to provide a helpful README for your asset with configuration examples.

bonsai.yml example

---
description: "#{repo}"
builds:
- platform: "linux"
  arch: "amd64"
  asset_filename: "#{repo}_#{version}_linux_amd64.tar.gz"
  sha_filename: "#{repo}_#{version}_sha512-checksums.txt"
  filter:
  -  "entity.system.os == 'linux'"
  -  "entity.system.arch == 'amd64'"

- platform: "Windows"
  arch: "amd64"
  asset_filename: "#{repo}_#{version}_windows_amd64.tar.gz"
  sha_filename: "#{repo}_#{version}_sha512-checksums.txt"
  filter:
  -  "entity.system.os == 'windows'"
  -  "entity.system.arch == 'amd64'"

bonsai.yml specification

description
description Project description.
required true
type String
example
description: "#{repo}"
builds
description Array of asset details per platform.
required true
type Array
example
builds:
- platform: "linux"
  arch: "amd64"
  asset_filename: "#{repo}_#{version}_linux_amd64.tar.gz"
  sha_filename: "#{repo}_#{version}_sha512-checksums.txt"
  filter:
  -  "entity.system.os == 'linux'"
  -  "entity.system.arch == 'amd64'"

Builds specification

platform
description Platform supported by the asset.
required true
type String
example
- platform: "linux"
arch
description Architecture supported by the asset.
required true
type String
example
  arch: "amd64"
asset_filename
description File name of the archive that contains the asset.
required true
type String
example
asset_filename: "#{repo}_#{version}_linux_amd64.tar.gz"
sha_filename
description SHA-512 checksum for the asset archive.
required true
type String
example
sha_filename: "#{repo}_#{version}_sha512-checksums.txt"
filter
description Filter expressions that describe the operating system and architecture supported by the asset.
required false
type Array
example
  filter:
  -  "entity.system.os == 'linux'"
  -  "entity.system.arch == 'amd64'"

Delete assets

As of Sensu Go 5.12, you can delete assets with the /assets (DELETE) endpoint or via sensuctl (sensuctl asset delete). When you remove an asset from Sensu, this does not remove references to the deleted asset in any other resource (including checks, filters, mutators, handlers, and hooks). You must also update resources and remove any reference to the deleted asset. Failure to do so will result in errors like sh: asset.sh: command not found.

Errors as a result of failing to remove the asset from checks and hooks will surface in the event data. Errors as a result of failing to remove the asset reference on a mutator, handler, or filter will only surface in the backend logs.

Deleting an asset does not delete the archive or downloaded files on disk. You must remove the archive and downloaded files from the asset cache manually.