feat(dns): use dns resolvers to for dns failover routing scenarios (#4)

Co-authored-by: Robert Schönthal <[email protected]>

Author: digitalkaoz

.github/workflows/test.yaml

@@ -60,10 +60,13 @@ jobs:
           docker logs statista_proxy
 
       - name: Test Docker Image with Cookie Strategy without cookie
+        id: test-cookie-no-cookie
+        continue-on-error: true
         run: |
           curl -Is localhost:80 | grep -i -e "x-proxy-flow: route-to-legacy"
 
       - name: Test Docker Image with Cookie Strategy with cookie
+        continue-on-error: true
         run: |
           curl -Is --cookie "my_app_routing=new" localhost:80 | grep -i -e "x-proxy-flow: route-to-new"
 
@@ -86,18 +89,26 @@ jobs:
           docker logs statista_proxy
 
       - name: Test Docker Image with Percentage Strategy backend selection
+        id: test-percentage-strategy
+        continue-on-error: true
         run: |
           curl -Is localhost:80 | grep -i -e "x-proxy-flow: route-to-percentage"
 
       - name: Test Docker Image with Percentage Strategy with sticky cookie on old domain
+        id: test-percentage-sticky-old-domain
+        continue-on-error: true
         run: |
           curl -Is localhost:80 --cookie "my_app=old_domain" | grep -i -e "server: Apache"
 
       - name: Test Docker Image with Percentage Strategy with sticky cookie on new domain
+        id: test-percentage-sticky-new-domain
+        continue-on-error: true
         run: |
           curl -Is localhost:80 --cookie "my_app=new_domain" | grep -i -e "x-served-by: cache-"
 
       - name: Test Docker Image with Percentage Strategy with round robin
+        id: test-percentage-round-robin
+        continue-on-error: true
         # sadly we dont know which server serves us first, so we have to check both
         run: |
           curl -Is localhost:80 | grep -i -e "server:" -e "x-served-by:" -e "set-cookie: my_app=new_domain; path=/" -e "set-cookie: my_app=old_domain; path=/"
@@ -107,53 +118,91 @@ jobs:
         if: success() || failure()
         run: docker rm -f statista_proxy
 
+      # validation TEMPLATE
+      #- name: name of the test
+      #  timeout-minutes: 1 # set so if the command runs successfully the test will fail
+      #  id: test-validation-percentage-new # important since all steps run and we collect the failure at then end
+      #  continue-on-error: true # important for allowing other steps to be run regardless of this one which might fail
+      #  run: |
+      #    ! docker run \ # important simply negate the exit code, since we expect the container to fail (which means succesfull validation)
+      #    -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 \
+      #    "${{ env.IMAGE_NAME }}"
+
       # variable validation
       - name: Run Docker Image with Invalid new Percentage
+        timeout-minutes: 1
+        id: test-validation-percentage-new
+        continue-on-error: true
         run: |
-          set +e
-
-          docker run \
+          ! docker run \
           -e STRATEGY=PERCENTAGE \
           -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 \
           -e PERCENTAGE_NEW=foo -e PERCENTAGE_OLD=50 \
           -e COOKIE_PERCENTAGE_NAME=my_app \
           "${{ env.IMAGE_NAME }}"
 
-          if [[ $? == 1 ]]; then exit 0; else exit 1; fi
-
       - name: Run Docker Image with Invalid old Percentage
+        timeout-minutes: 1
+        id: test-validation-percentage-old
+        continue-on-error: true
         run: |
-          set +e
-
-          docker run \
+          ! docker run \
           -e STRATEGY=PERCENTAGE \
           -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 \
           -e PERCENTAGE_NEW=50 -e PERCENTAGE_OLD=foo \
           -e COOKIE_PERCENTAGE_NAME=my_app \
           "${{ env.IMAGE_NAME }}"
 
-          if [[ $? == 1 ]]; then exit 0; else exit 1; fi
-
       - name: Run Docker Image with Invalid old domain
+        timeout-minutes: 1
+        id: test-validation-old-domain
+        continue-on-error: true
         run: |
-          set +e
-
-          docker run \
+          ! docker run \
           -e STRATEGY=PERCENTAGE \
           -e NEW_DOMAIN=apache.org:443 \
           -e COOKIE_PERCENTAGE_NAME=my_app \
           "${{ env.IMAGE_NAME }}"
 
-          if [[ $? == 1 ]]; then exit 0; else exit 1; fi
-
       - name: Run Docker Image with Invalid new domain
+        timeout-minutes: 1
+        id: test-validation-new-domain
+        continue-on-error: true
         run: |
-          set +e
-
-          docker run \
+          ! docker run \
           -e STRATEGY=PERCENTAGE \
           -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:lol \
           -e COOKIE_PERCENTAGE_NAME=my_app \
           "${{ env.IMAGE_NAME }}"
 
-          if [[ $? == 1 ]]; then exit 0; else exit 1; fi
+      - name: Run Docker Image with Invalid server count
+        timeout-minutes: 1
+        id: test-validation-server-count
+        continue-on-error: true
+        run: |
+          ! docker run \
+          -e STRATEGY=PERCENTAGE \
+          -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 \
+          -e COOKIE_PERCENTAGE_NAME=my_app \
+          -e SERVER_COUNT=foo \
+          "${{ env.IMAGE_NAME }}"
+
+      - name: Run Docker Image with Invalid DNS Resolver
+        timeout-minutes: 1
+        id: test-validation-dns-resolver
+        continue-on-error: true
+        run: |
+          ! docker run \
+          -e STRATEGY=PERCENTAGE \
+          -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 \
+          -e COOKIE_PERCENTAGE_NAME=my_app \
+          -e DNS_RESOLVER=foo \
+          "${{ env.IMAGE_NAME }}"
+
+      - name: Check for failures
+        if: always()
+        env:
+          STEPS_CONTEXT: ${{ toJson(steps) }}
+        run: |
+          set +e
+          ! echo "$STEPS_CONTEXT" | grep -q 'failure'

Dockerfile

@@ -1,6 +1,6 @@
 FROM haproxy:lts-alpine
 
-LABEL org.opencontainers.image.source=https://github.com/statista-oss/proxy-router
+LABEL org.opencontainers.image.source="https://github.com/statista-oss/proxy-router"
 LABEL org.opencontainers.image.description="haproxy configurable through env vars for different routing strategies"
 
 USER root

README.md

@@ -41,6 +41,14 @@ how much traffic should be routed to the old application
 ### PERCENTAGE_NEW
 how much traffic should be routed to the new application
 
+### DNS_RESOLVER (optional, default=1.1.1.1)
+The DNS resolver to use for resolving the domain names to IP addresses.
+If you want to reroute internal traffic you might want to change that.
+
+### SERVER_COUNT (optional, default=5)
+as we are using DNS Resolver we try to create a server for each IP address we get back from the DNS query. 
+This is the maximum amount of servers we will create. 
+
 
 ## Local Testing
 
@@ -54,7 +62,7 @@ docker build -t statista-proxy .
 run the container
 
 ```bash
-docker run -p80:80 -e STRATEGY=PERCENTAGE -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 -e PERCENTAGE_NEW=50 -e PERCENTAGE_OLD=50 -e COOKIE_PERCENTAGE_NAME=my_app statista_proxy
+docker run -p80:80 -e STRATEGY=PERCENTAGE -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 -e PERCENTAGE_NEW=50 -e PERCENTAGE_OLD=50 -e COOKIE_PERCENTAGE_NAME=my_app statista-proxy
 ```
 
 run requests (since its round robin every request should be flipped)
@@ -69,7 +77,7 @@ further requests made by the same client will stick to this server
 ### Cookie based routing
 
 ```bash
-docker run -p80:80 -e STRATEGY=COOKIE -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 -e COOKIE_STRATEGY_NAME="my_app_routing=new" statista_proxy
+docker run -p80:80 -e STRATEGY=COOKIE -e OLD_DOMAIN=haproxy.com:443 -e NEW_DOMAIN=apache.org:443 -e COOKIE_STRATEGY_NAME="my_app_routing=new" statista-proxy
 ```
 
 run requests (since its round robin every request should be flipped)

haproxy.cfg

@@ -10,18 +10,27 @@ global
   # default some environment variables
   presetenv PERCENTAGE_NEW "0"
   presetenv PERCENTAGE_OLD "100"
+  presetenv SERVER_COUNT "5"
+  presetenv DNS_RESOLVER "1.1.1.1:53"
 
   # we source them from the environment here to actually typecheck them
   set-var proc.percentage_new int("${PERCENTAGE_NEW}")
   set-var proc.percentage_old int("${PERCENTAGE_OLD}")
 
+  set-var proc.server_count int("${SERVER_COUNT}")
+
   #log stdout format raw local0
 
 defaults
   timeout connect 5s
   timeout client 1m
   timeout server 1m
   mode http
+  default-server  check
+  default-server  resolvers dns
+  default-server  resolve-prefer ipv4
+  default-server  init-addr last,libc,none
+  default-server  ssl verify required ca-file @system-ca
   #log global
   #option httplog
 
@@ -47,24 +56,30 @@ frontend http-in
 backend old_domain
   http-response set-header X-Proxy-Flow route-to-legacy
   option tcp-check
+  balance leastconn
 
-  server default_old "$OLD_DOMAIN" check ssl verify none
+  server-template default_old "$SERVER_COUNT" "$OLD_DOMAIN"
 
 backend percentage_strategy
   http-response set-header X-Proxy-Flow route-to-percentage
   option tcp-check
+  balance leastconn
 
   cookie "$COOKIE_PERCENTAGE_NAME" insert indirect
 
   # old domain
-  server old_domain_percentage "$OLD_DOMAIN" check cookie old_domain ssl verify none weight "$PERCENTAGE_OLD"
+  server-template old_domain_percentage "$SERVER_COUNT" "$OLD_DOMAIN" cookie old_domain weight "$PERCENTAGE_OLD"
 
   # new domain
-  server new_domain_percentage "$NEW_DOMAIN" check cookie new_domain ssl verify none weight "$PERCENTAGE_NEW"
+  server-template new_domain_percentage "$SERVER_COUNT" "$NEW_DOMAIN" cookie new_domain weight "$PERCENTAGE_NEW"
 
 backend cookie_strategy
+  balance leastconn
   http-response set-header X-Proxy-Flow route-to-new
   option tcp-check
 
-  server default_new "$NEW_DOMAIN" check ssl verify none
+  server-template default_new "$SERVER_COUNT" "$NEW_DOMAIN"
 
+resolvers dns
+  nameserver default "$DNS_RESOLVER"
+  accepted_payload_size 8192