AWS mediatailor: MediaTailor Functions limits: larger hook payloads, new response caching limits
Summary
Raises the POST_ADS_RESPONSE and PRE_MANIFEST_INSERTION input payload limit from 128 KB to 400 KB and output limit from 256 KB to 512 KB, clarifies that the input limit measures only the writable ads projection (not session variables), notes PRE_MANIFEST_INSERTION reaches the limit first, and adds a new 'Response caching limits' section documenting TtlMinimumSeconds/TtlMaximumSeconds ranges, cache key expression length (2,048 chars, authoring) and evaluated cache key length (1,024 chars, runtime).
Security assessment
The change is a quota/limit documentation update: it enlarges permitted hook payload sizes and documents caching parameter bounds (TTL ranges, cache key length enforced at authoring and runtime). Larger input payloads and cache-key-size caps are operational limits rather than fixes for a specific vulnerability, credential, IAM, or exposure issue, so there is no concrete security-incident evidence.
Evidence
+If the evaluated cache key exceeds 1,024 characters, MediaTailor doesn't send the request. For more information about response caching, see [Caching HTTP responses](./monetization-functions-caching.html).
Diff
diff --git a/mediatailor/latest/ug/monetization-functions-limits.md b/mediatailor/latest/ug/monetization-functions-limits.md index a227207..ba2c117 100644 --- a//mediatailor/latest/ug/monetization-functions-limits.md +++ b//mediatailor/latest/ug/monetization-functions-limits.md @@ -7 +7 @@ -Hook execution limitsExpression limitsFunction composition limitsHTTP request limitsResponse limitsOutput limitsAllowed JSONata functions +Hook execution limitsExpression limitsFunction composition limitsHTTP request limitsResponse caching limitsResponse limitsOutput limitsAllowed JSONata functions @@ -21,2 +21,2 @@ Hook | Limit | Value -`POST_ADS_RESPONSE` | Input payload size | 128 KB -`POST_ADS_RESPONSE` | Output size | 256 KB +`POST_ADS_RESPONSE` | Input payload size | 400 KB +`POST_ADS_RESPONSE` | Output size | 512 KB @@ -24,2 +24,2 @@ Hook | Limit | Value -`PRE_MANIFEST_INSERTION` | Input payload size | 128 KB -`PRE_MANIFEST_INSERTION` | Output size | 256 KB +`PRE_MANIFEST_INSERTION` | Input payload size | 400 KB +`PRE_MANIFEST_INSERTION` | Output size | 512 KB @@ -33 +33,3 @@ In addition to each hook's own timeout, the `PRE_ADS_REQUEST`, `POST_ADS_RESPONS -The input payload size limit applies to the serialized JSON input that MediaTailor builds for the `POST_ADS_RESPONSE` and `PRE_MANIFEST_INSERTION` hooks. If the input exceeds 128 KB, MediaTailor skips the hook invocation for that request. The output size limit caps the total serialized size that a function can write to the hook's writable namespace; output that exceeds 256 KB is discarded. +The input payload size limit applies to the ads projection that MediaTailor serializes for the `POST_ADS_RESPONSE` and `PRE_MANIFEST_INSERTION` hooks. It measures only the writable projection, not the full request, and does not count session variables. If the projection exceeds 400 KB, MediaTailor skips the hook invocation for that request. The output size limit caps the total serialized size that a function can write to the hook's writable namespace; output that exceeds 512 KB is discarded. + +MediaTailor projects slightly more data for `PRE_MANIFEST_INSERTION` than for `POST_ADS_RESPONSE` with the same ads, so when a session uses both hooks, `PRE_MANIFEST_INSERTION` reaches the 400 KB limit first. @@ -83,0 +86,11 @@ If a function sets a restricted header, MediaTailor accepts the function configu +## Response caching limits + +Limit | Value | Enforced at +---|---|--- +`TtlMinimumSeconds` | 1–300 seconds | Authoring +`TtlMaximumSeconds` | 1–300 seconds, and greater than or equal to `TtlMinimumSeconds` | Authoring +Cache key expression length | 2,048 characters | Authoring +Cache key length (after evaluation) | 1,024 characters | Runtime + +If the evaluated cache key exceeds 1,024 characters, MediaTailor doesn't send the request. For more information about response caching, see [Caching HTTP responses](./monetization-functions-caching.html). +