From 0bdf3516fc8f75e05b8be7ef868e2bdb877480a3 Mon Sep 17 00:00:00 2001
From: Maansi Prerna <maansiprerna@microsoft.com>
Date: Fri, 12 Jan 2024 15:22:34 +0530
Subject: [PATCH 1/3] adding example policies for tpm and circuit breaker

---
 examples/Rate limit by TPM.xml | 45 ++++++++++++++++++++++++++++++++++
 examples/circuitbreaker.xml    | 41 +++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 examples/Rate limit by TPM.xml
 create mode 100644 examples/circuitbreaker.xml

diff --git a/examples/Rate limit by TPM.xml b/examples/Rate limit by TPM.xml
new file mode 100644
index 0000000..ee569eb
--- /dev/null
+++ b/examples/Rate limit by TPM.xml	
@@ -0,0 +1,45 @@
+
+<policies>
+	<inbound>
+		<base />
+		<!--Priority Management Based on Subscription Keys:
+			Applies quotas based on the subscription key. -->
+		<choose>
+			<when condition="@(context.Subscription.Id == "subscription1")">
+				<!-- Rate limit by TPM 
+				Each subscription has its own TPM counter ('subscription1TPM' in this case) that tracks total tokens used per request. 
+				If the response status is 200, the counter increases by the token count obtained in the response body. 
+				If the counter hits the 500 TPM limit within 60 seconds, the request will not be forwarded to the backend.
+				Clients recieve 429 as the response status code.
+				 -->
+				<rate-limit-by-key calls="500" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"TPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" increment-count="@(context.Response.Body.As<JObject>(true).SelectToken("usage.total_tokens").ToObject<int>())" remaining-calls-header-name="remainingTPM" total-calls-header-name="totalTPM" />
+				<!-- Rate limit by RPM
+				Each subscription has its own RPM counter ('subscription1RPM' in this case) that tracks total requests per minute.
+				If the response status is 200, the counter increases by 1.
+				If the counter hits the 3 RPM limit within 60 seconds, the request will not be forwarded to the backend.
+				Clients recieve 429 as the response status code.
+				-->
+				<rate-limit-by-key calls="5" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"RPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" remaining-calls-header-name="remainingRPM" total-calls-header-name="totalRPM" />
+				<set-variable name="BusinessUnitName" value="EnterpriseEndUserChatBotMobile" />
+				<quota-by-key calls="100" renewal-period="300" counter-key="@(context.Subscription.Id)" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" />
+			</when>
+			<when condition="@(context.Subscription.Name == "subscription2")">
+				<!-- Rate limit by TPM -->
+				<rate-limit-by-key calls="200" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"TPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" increment-count="@(context.Response.Body.As<JObject>(true).SelectToken("usage.total_tokens").ToObject<int>())" remaining-calls-header-name="remainingTPM" total-calls-header-name="totalTPM" />
+				<!-- Rate limit by RPM -->
+				<rate-limit-by-key calls="3" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"RPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" remaining-calls-header-name="remainingRPM" total-calls-header-name="totalRPM" />
+				<set-variable name="BusinessUnitName" value="EnterpriseEndUserChatBotWeb" />
+				<quota-by-key calls="100" renewal-period="300" counter-key="@(context.Subscription.Id)" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" />
+			</when>
+			<otherwise>
+				<rate-limit-by-key calls="5" renewal-period="60" counter-key="@(context.Subscription.Id)" />
+				<set-variable name="BusinessUnitName" value="OtherSmallProducts" />
+				<quota-by-key calls="100" renewal-period="3600" counter-key="@(context.Subscription.Id)" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" />
+			</otherwise>
+		</choose>
+	</inbound>
+	<backend>
+		<!--The backend section inherits the base behavior without additional policies.-->
+		<base />
+	</backend>
+</policies>
\ No newline at end of file
diff --git a/examples/circuitbreaker.xml b/examples/circuitbreaker.xml
new file mode 100644
index 0000000..10d237c
--- /dev/null
+++ b/examples/circuitbreaker.xml
@@ -0,0 +1,41 @@
+<policies>
+    <inbound>
+        <base />
+        <!-- Cache lookup with default state to allow requests -->
+        <cache-lookup-value key="circuitBreakerState" variable-name="circuitBreakerState" default-value="true" />
+        <!-- Setting a default timeout -->
+        <set-variable name="circuitBreakerTimeoutSeconds" value="30" />
+        <choose>
+            <!-- Customize this for priority handling -->
+            <when condition="@(bool.Parse((string)context.Variables["circuitBreakerState"]) == false)">
+                <!-- Return a response immediately if the circuit breaker is tripped -->
+                <return-response>
+                    <set-status code="503" reason="Service Unavailable. Circuit tripped!" />
+                    <set-header name="Retry-After" exists-action="override">
+                        <value>@((string)context.Variables["circuitBreakerTimeoutSeconds"])</value>
+                    </set-header>
+                </return-response>
+            </when>
+        </choose>
+    </inbound>
+    <backend>
+        <base />
+    </backend>
+    <outbound>
+        <base />
+        <!-- Reset the circuit breaker on a successful response -->
+        <cache-store-value key="circuitBreakerState" value="true" duration="300" />
+    </outbound>
+    <on-error>
+        <base />
+        <!-- Check for errors -->
+        <!-- Customize this for specific errors/priority handling -->
+        <choose>
+            <when condition="@(context.Response.StatusCode >= 300)">
+                <!-- Trip the circuit breaker on an error -->
+                <cache-store-value key="circuitBreakerState" value="false" duration="@(int.Parse((string)context.Variables["circuitBreakerTimeoutSeconds"]))" />
+                <!-- Continue with default error handling -->
+            </when>
+        </choose>
+    </on-error>
+</policies>
\ No newline at end of file

From 95e229eb503f0730761883e1c61a067c21f69850 Mon Sep 17 00:00:00 2001
From: Maansi Prerna <maansiprerna@microsoft.com>
Date: Fri, 12 Jan 2024 15:44:55 +0530
Subject: [PATCH 2/3] removing rpm policies

---
 examples/Rate limit by TPM.xml | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/examples/Rate limit by TPM.xml b/examples/Rate limit by TPM.xml
index ee569eb..d5ba1dc 100644
--- a/examples/Rate limit by TPM.xml	
+++ b/examples/Rate limit by TPM.xml	
@@ -13,28 +13,13 @@
 				Clients recieve 429 as the response status code.
 				 -->
 				<rate-limit-by-key calls="500" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"TPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" increment-count="@(context.Response.Body.As<JObject>(true).SelectToken("usage.total_tokens").ToObject<int>())" remaining-calls-header-name="remainingTPM" total-calls-header-name="totalTPM" />
-				<!-- Rate limit by RPM
-				Each subscription has its own RPM counter ('subscription1RPM' in this case) that tracks total requests per minute.
-				If the response status is 200, the counter increases by 1.
-				If the counter hits the 3 RPM limit within 60 seconds, the request will not be forwarded to the backend.
-				Clients recieve 429 as the response status code.
-				-->
-				<rate-limit-by-key calls="5" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"RPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" remaining-calls-header-name="remainingRPM" total-calls-header-name="totalRPM" />
-				<set-variable name="BusinessUnitName" value="EnterpriseEndUserChatBotMobile" />
-				<quota-by-key calls="100" renewal-period="300" counter-key="@(context.Subscription.Id)" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" />
 			</when>
 			<when condition="@(context.Subscription.Name == "subscription2")">
 				<!-- Rate limit by TPM -->
 				<rate-limit-by-key calls="200" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"TPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" increment-count="@(context.Response.Body.As<JObject>(true).SelectToken("usage.total_tokens").ToObject<int>())" remaining-calls-header-name="remainingTPM" total-calls-header-name="totalTPM" />
-				<!-- Rate limit by RPM -->
-				<rate-limit-by-key calls="3" renewal-period="60" counter-key="@(String.Concat(context.Subscription.Id,"RPM"))" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" remaining-calls-header-name="remainingRPM" total-calls-header-name="totalRPM" />
-				<set-variable name="BusinessUnitName" value="EnterpriseEndUserChatBotWeb" />
-				<quota-by-key calls="100" renewal-period="300" counter-key="@(context.Subscription.Id)" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" />
 			</when>
 			<otherwise>
 				<rate-limit-by-key calls="5" renewal-period="60" counter-key="@(context.Subscription.Id)" />
-				<set-variable name="BusinessUnitName" value="OtherSmallProducts" />
-				<quota-by-key calls="100" renewal-period="3600" counter-key="@(context.Subscription.Id)" increment-condition="@(context.Response.StatusCode >= 200 && context.Response.StatusCode < 400)" />
 			</otherwise>
 		</choose>
 	</inbound>

From c676228aa9a3bec2fba02009e9932651c22fad34 Mon Sep 17 00:00:00 2001
From: Maansi Prerna <maansiprerna@microsoft.com>
Date: Mon, 15 Jan 2024 16:54:16 +0530
Subject: [PATCH 3/3] adding link in the readme and removing circuitbreaker

---
 examples/README.md          |  1 +
 examples/circuitbreaker.xml | 41 -------------------------------------
 2 files changed, 1 insertion(+), 41 deletions(-)
 delete mode 100644 examples/circuitbreaker.xml

diff --git a/examples/README.md b/examples/README.md
index d8f614e..4ec4460 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -51,3 +51,4 @@ Overview
 | <a href="Extracting multiple values from xml documents.policy.xml">Extract multiple values from xml documents</a>                                                                  | Uses an intermediate json object to provide easy access to extracted values from an xml document.                                                                                                                                     |
 | <a href="Return a blob URL signed with a user delegation SAS token.xml">Return a blob URL signed with a user delegation SAS token</a>                                              | Demonstrates how to check if a blob exists and then return the URL of the blob signed with a User Delegation SAS token leveraging Managed Identity.                                                                                   | 
 | <a href="oauth-proxy/readme.md">OAuth Reverse Proxy</a>                                              | Demonstrates how to implement an OAuth Reverse Proxy to provide OIDC authentication in-front of a Web Application behind Azure API Management.                                                                                   | 
+| <a href="Rate limit by TPM.xml">Rate limit by TPM (Tokens per minute)</a>                                              | Demonstrates how to implement a TPM based rate limiting policy in Azure API Management.                                                                                   | 
diff --git a/examples/circuitbreaker.xml b/examples/circuitbreaker.xml
deleted file mode 100644
index 10d237c..0000000
--- a/examples/circuitbreaker.xml
+++ /dev/null
@@ -1,41 +0,0 @@
-<policies>
-    <inbound>
-        <base />
-        <!-- Cache lookup with default state to allow requests -->
-        <cache-lookup-value key="circuitBreakerState" variable-name="circuitBreakerState" default-value="true" />
-        <!-- Setting a default timeout -->
-        <set-variable name="circuitBreakerTimeoutSeconds" value="30" />
-        <choose>
-            <!-- Customize this for priority handling -->
-            <when condition="@(bool.Parse((string)context.Variables["circuitBreakerState"]) == false)">
-                <!-- Return a response immediately if the circuit breaker is tripped -->
-                <return-response>
-                    <set-status code="503" reason="Service Unavailable. Circuit tripped!" />
-                    <set-header name="Retry-After" exists-action="override">
-                        <value>@((string)context.Variables["circuitBreakerTimeoutSeconds"])</value>
-                    </set-header>
-                </return-response>
-            </when>
-        </choose>
-    </inbound>
-    <backend>
-        <base />
-    </backend>
-    <outbound>
-        <base />
-        <!-- Reset the circuit breaker on a successful response -->
-        <cache-store-value key="circuitBreakerState" value="true" duration="300" />
-    </outbound>
-    <on-error>
-        <base />
-        <!-- Check for errors -->
-        <!-- Customize this for specific errors/priority handling -->
-        <choose>
-            <when condition="@(context.Response.StatusCode >= 300)">
-                <!-- Trip the circuit breaker on an error -->
-                <cache-store-value key="circuitBreakerState" value="false" duration="@(int.Parse((string)context.Variables["circuitBreakerTimeoutSeconds"]))" />
-                <!-- Continue with default error handling -->
-            </when>
-        </choose>
-    </on-error>
-</policies>
\ No newline at end of file