prep release: v1.39.0 (#4597)

## 🚀 Features

### Specify Trace ID Formatting ([PR
#4530](#4530))

This adds the ability to specify the format of the trace ID in the
response headers of the supergraph service.

An example configuration making use of this feature is shown below:
```yaml
telemetry:
  apollo:
    client_name_header: name_header
    client_version_header: version_header
  exporters:
    tracing:
      experimental_response_trace_id:
        enabled: true
        header_name: trace_id
        format: decimal # Optional, defaults to hexadecimal
```

If the format is not specified, then the trace ID will continue to be in
hexadecimal format.

By [@nicholascioli](https://github.com/nicholascioli) in
#4530

### Introduce support for progressive `@override` ([PR
#4521](#4521))

The change brings support for progressive `@override`, which allows
dynamically overriding root fields and entity fields in the schema. This
feature is enterprise only and requires a license key to be used.

A new `label` argument is added to the `@override` directive in order to
indicate the field is dynamically overridden. Labels can come in two
forms:
1) String matching the form `percent(x)`: The router resolves these
labels based on the `x` value. For example, `percent(50)` will route 50%
of requests to the overridden field and 50% of requests to the original
field.
2) Arbitrary string matching the regex `^[a-zA-Z][a-zA-Z0-9_-:./]*$`:
These labels are expected to be resolved externally via coprocessor. A
coprocessor a supergraph request hook can inspect and modify the context
of a request in order to inform the router which labels to use during
query planning.

Please consult the docs for more information on how to use this feature
and how to implement a coprocessor for label resolution.

By [@trevorscheer](https://github.com/TrevorScheer) in
#4521

### Add a new selector to get all baggage key values in span attributes
([Issue #4425](#4425))

If you have several baggage items and would like to add all of them
directly as span attributes, for example `baggage: my_item=test,
my_second_item=bar` will add 2 span attributes `my_item=test` and
`my_second_item=bar`.

Example of configuration:

```yaml
telemetry:
  instrumentation:
    spans:
      router:
        attributes:
          baggage: true
```

By [@bnjjj](https://github.com/bnjjj) in
#4537

### Create a trace during router creation and plugin initialization
([Issue #4472](#4472))

When the router starts or reload, it will now generate a trace with
spans for query planner creation, schema parsing, plugin initialization
and request pipeline creation. This will help in debugging any issue
during startup, especially in plugins creation

By [@Geal](https://github.com/Geal) in
#4480

### Add static attribute on specific span in telemetry settings ([Issue
#4561](#4561))

Example of configuration:

```yaml
telemetry:
  instrumentation:
    spans:
      router:
        attributes:
          "my_attribute": "constant_value"
      supergraph:
        attributes:
          "my_attribute": "constant_value"
      subgraph:
        attributes:
          "my_attribute": "constant_value"
```

By [@bnjjj](https://github.com/bnjjj) in
#4566

## 🐛 Fixes

### Order HPA target so that kubernetes does not rewrite ([Issue
#4435](#4435))

This update addresses an OutOfSync issue in ArgoCD applications when
Horizontal Pod Autoscaler (HPA) is configured with both memory and CPU
limits.
Previously, the live and desired manifests within Kubernetes were not
consistently sorted, leading to persistent OutOfSync states in ArgoCD.
This change implements a sorting mechanism for HPA targets within the
Helm chart, ensuring alignment with Kubernetes' expected order.
This fix proactively resolves the sync discrepancies while using HPA,
circumventing the need to wait for Kubernetes' issue resolution
(kubernetes/kubernetes#74099).

By [@cyberhck](https://github.com/cyberhck) in
#4436

### Reactivate log events in traces ([PR
#4486](#4486))

This fixes a regression introduced in #2999, where events were not sent
with traces anymore due to too aggressive sampling

By [@Geal](https://github.com/Geal) in
#4486

### Fix inconsistency in environment variable parsing for telemetry
([Issue
#3203](https://github.com/apollographql/router/issues/ISSUE_NUMBER))

Previously, the router would complain when using the rover
recommendation of `APOLLO_TELEMETRY_DISABLED=1` environment
variable. Now any non-falsey value can be used, such as 1, yes, on,
etc..

By [@nicholascioli](https://github.com/nicholascioli) in
#4549

### Store static pages in `Bytes` structure to avoid expensive
allocation per request ([PR
#4528](#4528))

The `CheckpointService` created by the `StaticPageLayer` caused a
non-insignificant amount of memory to be allocated on every request. The
service stack gets cloned on every request, and so does the rendered
template.

The template is now stored in a `Bytes` struct instead which is cheap to
clone.

By [@xuorig](https://github.com/xuorig) in
#4528

### Fix header propagation issues ([Issue
#4312](#4312)), ([Issue
#4398](#4398))

This fixes two header propagation issues:
* if a client request header has already been added to a subgraph
request due to another header propagation rule, then it is only added
once
* `Accept`, `Accept-Encoding` and `Content-Encoding` were not in the
list of reserved headers that cannot be propagated. They are now in that
list because those headers are set explicitely by the Router in its
subgraph requests

There is a potential regression: if a router deployment was accidentally
relying on header propagation to compress subgraph requests, then it
will not work anymore because `Content-Encoding` is not propagated
anymore. Instead it should be set up from the `traffic_shaping` section
of the Router configuration:

```yaml
traffic_shaping:
  all:
    compression: gzip
  subgraphs: # Rules applied to requests from the router to individual subgraphs
    products:
      compression: identity
```

By [@Geal](https://github.com/Geal) in
#4535

## 🧪 Experimental

### Move cacheability metrics to the entity cache plugin ([Issue
#4253](#4253))

The metric was generated in the telemetry plugin before, but it was not
very convenient to keep it there. This adds more configuration:
- enable or disable the metrics
- set the metrics storage TTL (default is 60s)
- the metric's typename attribute is disabled by default. Activating it
can greatly increase the cardinality

This also includes some cleanup and performance improvements

By [@Geal](https://github.com/Geal) in
#4469

---------

Co-authored-by: Edward Huang <[email protected]>
Co-authored-by: Jeremy Lempereur <[email protected]>
Co-authored-by: Jesse Rosenberger <[email protected]>

CHANGELOG.md

@@ -4,6 +4,167 @@ All notable changes to Router will be documented in this file.
 
 This project adheres to [Semantic Versioning v2.0.0](https://semver.org/spec/v2.0.0.html).
 
+# [1.39.0] - 2024-02-05
+
+## 🚀 Features
+
+### Introduce support for progressive `@override` ([PR #4521](https://github.com/apollographql/router/pull/4521))
+
+> ⚠️ This is an [Enterprise feature](https://www.apollographql.com/blog/platform/evaluating-apollo-router-understanding-free-and-open-vs-commercial-features/) of the Apollo Router. It requires an organization with a [GraphOS Enterprise plan](https://www.apollographql.com/pricing/).
+>
+> If your organization doesn't currently have an Enterprise plan, you can test out this functionality by signing up for a free Enterprise trial.
+
+The change brings support for progressive `@override`, which allows dynamically overriding root fields and entity fields in the schema. This feature is enterprise only and requires a license key to be used.
+
+A new `label` argument is added to the `@override` directive in order to indicate the field is dynamically overridden. Labels can come in two forms:
+1) String matching the form `percent(x)`: The router resolves these labels based on the `x` value. For example, `percent(50)` will route 50% of requests to the overridden field and 50% of requests to the original field.
+2) Arbitrary string matching the regex `^[a-zA-Z][a-zA-Z0-9_-:./]*$`: These labels are expected to be resolved externally via coprocessor. A supergraph request hook can inspect and modify the context of a request in order to inform the router which labels to use during query planning.
+
+Please consult the docs for more information on how to use this feature and how to implement a coprocessor for label resolution.
+
+By [@TrevorScheer](https://github.com/TrevorScheer) in https://github.com/apollographql/router/pull/4521
+
+### Specify trace ID formatting ([PR #4530](https://github.com/apollographql/router/pull/4530))
+
+You can specify the format of the trace ID in the response headers of the supergraph service.
+
+An example configuration using this feature:
+```yaml
+telemetry:
+  apollo:
+    client_name_header: name_header
+    client_version_header: version_header
+  exporters:
+    tracing:
+      experimental_response_trace_id:
+        enabled: true
+        header_name: trace_id
+        format: decimal # Optional, defaults to hexadecimal
+```
+
+If the format is not specified, then the trace ID will continue to be in hexadecimal format.
+
+By [@nicholascioli](https://github.com/nicholascioli) in https://github.com/apollographql/router/pull/4530
+
+### Add selector to get all baggage key values in span attributes ([Issue #4425](https://github.com/apollographql/router/issues/4425))
+
+Previously, baggage items were configured as standard attributes in `router.yaml`, and adding a new baggage item required a configuration update and router rerelease. 
+
+This release supports a new configuration that enables baggage items to be added automatically as span attributes. 
+
+If you have several baggage items and would like to add all of them directly as span attributes (for example, `baggage: my_item=test, my_second_item=bar`), setting `baggage: true` will add automatically add two span attributes, `my_item=test` and `my_second_item=bar`.
+
+An example configuration:
+
+```yaml
+telemetry:
+  instrumentation:
+    spans:
+      router:
+        attributes:
+          baggage: true
+```
+
+
+By [@bnjjj](https://github.com/bnjjj) in https://github.com/apollographql/router/pull/4537
+
+### Create a trace during router creation and plugin initialization ([Issue #4472](https://github.com/apollographql/router/issues/4472))
+
+When the router starts or reloads, it will now generate a trace with spans for query planner creation, schema parsing, plugin initialisation and request pipeline creation. This will help debugging any issue during startup, especially during plugins creation.
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/4480
+
+### Allow adding static attributes on specific spans in telemetry settings ([Issue #4561](https://github.com/apollographql/router/issues/4561))
+
+It is now possible to add static attributes to spans, defined in the configuration file.
+
+Example of configuration:
+
+```yaml
+telemetry:
+  instrumentation:
+    spans:
+      router:
+        attributes:
+          "my_attribute": "constant_value"
+      supergraph:
+        attributes:
+          "my_attribute": "constant_value"
+      subgraph:
+        attributes:
+          "my_attribute": "constant_value"
+```
+
+By [@bnjjj](https://github.com/bnjjj) in https://github.com/apollographql/router/pull/4566
+
+## 🐛 Fixes
+
+### Order HPA targets to resolve OutOfSync states ([Issue #4435](https://github.com/apollographql/router/issues/4435))
+
+This update addresses an `OutOfSync` issue in ArgoCD applications when Horizontal Pod Autoscaler (HPA) is configured with both memory and CPU limits.
+Previously, the live and desired manifests within Kubernetes were not consistently sorted, leading to persistent `OutOfSync` states in ArgoCD.
+This change implements a sorting mechanism for HPA targets within the Helm chart, ensuring alignment with Kubernetes' expected order.
+This fix proactively resolves the sync discrepancies while using HPA, circumventing the need to wait for Kubernetes' issue resolution (kubernetes/kubernetes#74099).
+
+By [@cyberhck](https://github.com/cyberhck) in https://github.com/apollographql/router/pull/4436
+
+### Reactivate log events in traces ([PR #4486](https://github.com/apollographql/router/pull/4486))
+
+This fixes a regression introduced in #2999, where events were not sent with traces anymore due to too aggressive sampling
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/4486
+
+### Fix inconsistency in environment variable parsing for telemetry ([Issue #3203](https://github.com/apollographql/router/issues/ISSUE_NUMBER))
+
+Previously, the router would complain when using the rover recommendation of `APOLLO_TELEMETRY_DISABLED=1` environment
+variable. Now any non-falsey value can be used, such as 1, yes, on, etc..
+
+By [@nicholascioli](https://github.com/nicholascioli) in https://github.com/apollographql/router/pull/4549
+
+### Store static pages in `Bytes` structure to avoid expensive allocation per request ([PR #4528](https://github.com/apollographql/router/pull/4528))
+
+The `CheckpointService` created by the `StaticPageLayer` caused a non-insignificant amount of memory to be allocated on every request. The service stack gets cloned on every request, and so does the rendered template.
+
+The template is now stored in a `Bytes` struct instead which is cheap to clone.
+
+By [@xuorig](https://github.com/xuorig) in https://github.com/apollographql/router/pull/4528
+
+### Fix header propagation issues ([Issue #4312](https://github.com/apollographql/router/issues/4312)), ([Issue #4398](https://github.com/apollographql/router/issues/4398))
+
+This fixes two header propagation issues:
+* if a client request header has already been added to a subgraph request due to another header propagation rule, then it is only added once
+* `Accept`, `Accept-Encoding` and `Content-Encoding` were not in the list of reserved headers that cannot be propagated. They are now in that list because those headers are set explicitely by the Router in its subgraph requests
+
+There is a potential change in behavior: if a router deployment was accidentally relying on header propagation to compress subgraph requests, then it will not work anymore because `Content-Encoding` is not propagated anymore. Instead it should be set up from the `traffic_shaping` section of the Router configuration:
+
+```yaml
+traffic_shaping:
+  all:
+    compression: gzip
+  subgraphs: # Rules applied to requests from the router to individual subgraphs
+    products:
+      compression: identity
+```
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/4535
+
+## 🧪 Experimental
+
+### Move cacheability metrics to the entity cache plugin ([Issue #4253](https://github.com/apollographql/router/issues/4253))
+
+Cacheability metrics have been moved from the telemetry plugin to the entity cache plugin.
+
+New configuration has been added:
+- Enabling or disabling the metrics
+- Setting the metrics storage TTL (default is 60s)
+- Disabling the metric's typename attribute by default. (Activating it can greatly increase the cardinality.)
+
+Cleanup and performance improvements have also been implemented.
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/4469
+
+
+
 # [1.38.0] - 2024-01-19
 
 ## 🚀 Features

Cargo.lock

@@ -258,7 +258,7 @@ dependencies = [
 
 [[package]]
 name = "apollo-router"
-version = "1.39.0-rc.0"
+version = "1.39.0"
 dependencies = [
  "access-json",
  "anyhow",
@@ -413,7 +413,7 @@ dependencies = [
 
 [[package]]
 name = "apollo-router-benchmarks"
-version = "1.39.0-rc.0"
+version = "1.39.0"
 dependencies = [
  "apollo-parser",
  "apollo-router",
@@ -429,7 +429,7 @@ dependencies = [
 
 [[package]]
 name = "apollo-router-scaffold"
-version = "1.39.0-rc.0"
+version = "1.39.0"
 dependencies = [
  "anyhow",
  "cargo-scaffold",

apollo-router-benchmarks/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "apollo-router-benchmarks"
-version = "1.39.0-rc.0"
+version = "1.39.0"
 authors = ["Apollo Graph, Inc. <[email protected]>"]
 edition = "2021"
 license = "Elastic-2.0"

apollo-router-scaffold/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "apollo-router-scaffold"
-version = "1.39.0-rc.0"
+version = "1.39.0"
 authors = ["Apollo Graph, Inc. <[email protected]>"]
 edition = "2021"
 license = "Elastic-2.0"

apollo-router-scaffold/templates/base/Cargo.toml

@@ -22,7 +22,7 @@ apollo-router = { path ="{{integration_test}}apollo-router" }
 apollo-router = { git="https://github.com/apollographql/router.git", branch="{{branch}}" }
 {{else}}
 # Note if you update these dependencies then also update xtask/Cargo.toml
-apollo-router = "1.39.0-rc.0"
+apollo-router = "1.39.0"
 {{/if}}
 {{/if}}
 async-trait = "0.1.52"

apollo-router-scaffold/templates/base/xtask/Cargo.toml

@@ -13,7 +13,7 @@ apollo-router-scaffold = { path ="{{integration_test}}apollo-router-scaffold" }
 {{#if branch}}
 apollo-router-scaffold = { git="https://github.com/apollographql/router.git", branch="{{branch}}" }
 {{else}}
-apollo-router-scaffold = { git = "https://github.com/apollographql/router.git", tag = "v1.39.0-rc.0" }
+apollo-router-scaffold = { git = "https://github.com/apollographql/router.git", tag = "v1.39.0" }
 {{/if}}
 {{/if}}
 anyhow = "1.0.58"