Use ASMCompressor to configure response compression for application services - Alibaba Cloud Service Mesh

When microservices communicate over HTTP, response payloads can consume significant bandwidth, especially for text-based content like JSON, HTML, and CSS. ASMCompressor lets you add compression filters at the proxy layer so that all services share a single, consistent compression configuration instead of implementing compression separately in each language or framework.

ASMCompressor supports two compression algorithms:

Algorithm	Compression ratio	Speed	Best for
Gzip	Good	Fast compression and decompression	Both static and dynamic content. Widely supported by browsers and web servers.
Brotli	Higher than Gzip	Slower compression, faster decompression	Static content such as HTML, CSS, and JavaScript files.

Prerequisites

A Container Service for Kubernetes (ACK) cluster added to a Service Mesh (ASM) instance version 1.21 or later. For more information, see Add a cluster to an ASM instance and Update an ASM instance.
An ingress gateway deployed.
The Bookinfo sample application deployed in the ASM instance. For more information, see Deploy an application in an ACK cluster that is added to an ASM instance.
Istio resources configured to route traffic to different service versions. For more information, see Use Istio resources to route traffic to different versions of a service.

Step 1: Record the baseline response size

Before enabling compression, record the uncompressed response size. This baseline lets you measure the compression ratio later.

Get the IP address of the ingress gateway.
1. Log on to the ASM console. In the left-side navigation pane, choose Service Mesh > Mesh Management.
2. On the Mesh Management page, click the name of the ASM instance. In the left-side navigation pane, choose ASM Gateways > Ingress Gateway.
3. On the Ingress Gateway page, find the value of Service address.
Open http://<ASM-gateway-address>/productpage in a browser.
Open the browser developer tools and check the response size for the productpage request. The response size is approximately 5.5 KB without compression.

Step 2: Enable Gzip compression

Create an ASMCompressor resource to enable Gzip compression on the ingress gateway.

Create a file named ingressgateway-gzip.yaml with the following content:

For more information about the fields, see ASMCompressor field descriptions.

Expand to view the ingressgateway-gzip.yaml

apiVersion: istio.alibabacloud.com/v1beta1
kind: ASMCompressor
metadata:
  name: ingressgateway-gzip
  namespace: istio-system
spec:
  compressor_library:
    gzip:
      compression_level: BEST_COMPRESSION
      compression_strategy: DEFAULT_STRATEGY
      memory_level: 9
      window_bits: 15
  isGateway: true
  portNumber: 80
  request_direction_config:    # Disable request-direction compression
    common_config:
      enabled:
        default_value: false
        runtime_key: NOT_EXISTENT_KEY
  response_direction_config:   # Enable response-direction compression
    common_config:
      content_type:
      - application/json
      - text/plain
      - text/html
      min_content_length: 100
    disable_on_etag_header: true
  workloadSelector:
    labels:
      istio: ingressgateway

Apply the configuration:

kubectl apply -f ingressgateway-gzip.yaml

Step 3: Verify Gzip compression

Open http://<ASM-gateway-address>/productpage in a browser.
Open the browser developer tools and check the response size for the productpage request. The response size drops from 5.5 KB to approximately 1.8 KB, confirming that Gzip compression is active.

Step 4: Enable and verify Brotli compression

This step adds a test route for the /helloworld path and applies Brotli compression to it.

Add a test route

Add the following directResponse block to the spec.http section of the Bookinfo virtual service (bookinfo.yaml):

- directResponse:
    body:
      string: >-
        Hello, world! Hello, world! Hello, world! Hello, world! Hello,
        world! Hello, world! Hello, world! Hello, world! Hello, world!
        Hello, world!
         Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world!
          Hello, world! Hello, world! Hello, world! Hello, world!
    status: 200
  match:
    - uri:
        prefix: /helloworld

The complete bookinfo.yaml file after modification:

View the complete bookinfo.yaml

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: bookinfo
spec:
  gateways:
    - bookinfo-gateway
  hosts:
    - '*'
  http:
    - directResponse:
        body:
          string: >-
            Hello, world! Hello, world! Hello, world! Hello, world! Hello,
            world! Hello, world! Hello, world! Hello, world! Hello, world!
            Hello, world!
             Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world!
              Hello, world! Hello, world! Hello, world! Hello, world!
        status: 200
      match:
        - uri:
            prefix: /helloworld
    - match:
        - uri:
            exact: /productpage
        - uri:
            prefix: /static
        - uri:
            exact: /login
        - uri:
            exact: /logout
        - uri:
            prefix: /api/v1/products
      route:
        - destination:
            host: productpage
            port:
              number: 9080

Apply the virtual service:
```
kubectl apply -f bookinfo.yaml
```

Create the Brotli ASMCompressor resource

Create a file named ingressgateway-brotli.yaml with the following content:

For more information about the fields, see ASMCompressor field descriptions.

Expand to view the ingressgateway-brotli.yaml file

apiVersion: istio.alibabacloud.com/v1beta1
kind: ASMCompressor
metadata:
  name: ingressgateway-brotli
  namespace: istio-system
spec:
  compressor_library:
    brotli:
      quality: 5
      window_bits: 15
  isGateway: true
  portNumber: 80
  request_direction_config:    # Disable request-direction compression
    common_config:
      enabled:
        default_value: false
        runtime_key: NOT_EXISTENT_KEY
  response_direction_config:
    common_config:
      content_type:
      - application/json
      - text/plain
      - text/html
      min_content_length: 100
    disable_on_etag_header: true
  workloadSelector:
    labels:
      istio: ingressgateway

Apply the configuration:

kubectl apply -f ingressgateway-brotli.yaml

Verify Brotli compression

Send a request with the Accept-Encoding: br header and save the response:

curl -H "Accept-Encoding: br" http://<ASM-gateway-address>/helloworld > out.br

Install the Brotli command-line tool:
- macOS: brew install brotli
- Windows: Download the binary from the Brotli GitHub releases page.
Decompress the saved response:
```
brotli -d out.br
```
If decompression succeeds and the output file contains the expected content, Brotli compression is working correctly.

Step 5: Disable compression for a specific route

By default, the ASMCompressor resource applies compression to all matching responses. To disable compression on a specific route while keeping it enabled for others, use per_route_configs.

This example disables compression on the /helloworld route while keeping it active for /productpage.

Confirm that compression is active on all routes

Run the following commands to compare compressed and uncompressed response sizes for both paths:

curl http://<ASM-gateway-address>/helloworld > helloworld_no_compress.html
curl -H "Accept-Encoding: br" http://<ASM-gateway-address>/helloworld > helloworld_compress.html
curl http://<ASM-gateway-address>/productpage > productpage_no_compress.html
curl -H "Accept-Encoding: br" http://<ASM-gateway-address>/productpage > productpage_compress.html

Check the file sizes:

ls -lh

Expected output:

-rw-r--r--@ 1 user  staff    37B  5 28 18:16 helloworld_compress.html
-rw-r--r--@ 1 user  staff   324B  5 28 18:15 helloworld_no_compress.html
-rw-r--r--@ 1 user  staff   1.2K  5 28 18:17 productpage_compress.html
-rw-r--r--@ 1 user  staff   5.2K  5 28 18:16 productpage_no_compress.html

Both paths return smaller responses when compression is requested.

Add a route name to the virtual service

To target a specific route in the per-route configuration, assign a name to the route in the virtual service.

Add name: helloworld-route to the /helloworld route in bookinfo.yaml:

View the modified bookinfo.yaml

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: bookinfo
spec:
  gateways:
    - bookinfo-gateway
  hosts:
    - '*'
  http:
    - directResponse:
        body:
          string: >-
            Hello, world! Hello, world! Hello, world! Hello, world! Hello,
            world! Hello, world! Hello, world! Hello, world! Hello, world!
            Hello, world!
             Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world! Hello, world!
              Hello, world! Hello, world! Hello, world! Hello, world!
        status: 200
      match:
        - uri:
            prefix: /helloworld
      name: helloworld-route    # Route name used by per_route_configs to match this route
    - match:
        - uri:
            exact: /productpage
        - uri:
            prefix: /static
        - uri:
            exact: /login
        - uri:
            exact: /logout
        - uri:
            prefix: /api/v1/products
      route:
        - destination:
            host: productpage
            port:
              number: 9080

Add a per-route override to ASMCompressor

Update the ASMCompressor resource to disable compression on the helloworld-route:

apiVersion: istio.alibabacloud.com/v1beta1
kind: ASMCompressor
metadata:
  name: ingressgateway-gzip
  namespace: istio-system
spec:
  compressor_library:
    brotli:
      quality: 5
      window_bits: 15
  isGateway: true
  portNumber: 80
  request_direction_config:    # Disable request-direction compression
    common_config:
      enabled:
        default_value: false
        runtime_key: NOT_EXISTENT_KEY
  response_direction_config:
    common_config:
      content_type:
      - application/json
      - text/plain
      - text/html
      min_content_length: 100
    disable_on_etag_header: true
  per_route_configs:            # Route-level overrides
  - disabled: true
    route_match:
      vhost:
        route:
          name: helloworld-route    # Must match the route name in the VirtualService
  workloadSelector:
    labels:
      istio: ingressgateway

Verify the per-route override

Send a compressed request to the /helloworld path:

curl -H "Accept-Encoding: br" http://<ASM-gateway-address>/helloworld > helloworld_route_disabled.html

Compare the file sizes:

ls -lh

Expected output:

-rw-r--r--@ 1 user  staff    37B  5 28 18:16 helloworld_compress.html
-rw-r--r--@ 1 user  staff   324B  5 28 18:15 helloworld_no_compress.html
-rw-r--r--@ 1 user  staff   324B  5 28 19:29 helloworld_route_disabled.html
-rw-r--r--@ 1 user  staff   1.3K  5 28 19:30 productpage_compress.html
-rw-r--r--@ 1 user  staff   5.2K  5 28 18:16 productpage_no_compress.html

The /helloworld response is now 324 B (same as the uncompressed size), confirming that compression is disabled for this route. The /productpage response remains compressed at 1.3 KB.