docs: Add feature flags support to Elixir (#10588)

Co-authored-by: Ian Vanagas <[email protected]>

contents/blog/how-to-measure-product-engagement.md

@@ -24,7 +24,11 @@ In this article we’ll take a look at why strong customer engagement metrics ar
 
 - [What is product engagement?](#what-is-product-engagement)
 - [What are product engagement metrics?](#what-are-product-engagement-metrics)
+  - [Common engagement metrics](#common-engagement-metrics)
 - [What is the best way to measure product engagement?](#what-is-the-best-way-to-measure-product-engagement)
+  - [Active users](#active-users)
+  - [Stickiness](#stickiness)
+  - [Adoption](#adoption)
 - [What tools are good for tracking product engagement?](#what-tools-are-good-for-tracking-product-engagement)
 - [Further reading](#further-reading)
 
@@ -88,7 +92,7 @@ An easier way to track this is to use a tool such as PostHog, which has a dedica
 Adoption represents the number of users using key features in your product.
 Each new feature presents an opportunity for additional customer value. Low adoption implies that you’re offering something which users don’t need, or that there’s something wrong with the feature itself. High adoption means users are flocking to a new feature.
 
-If users are paying for features they don’t use then it lowers the perceived value, so it’s essential to keep an eye on what isn’t working and rollback where necessary. That’s why PostHog offers tools like [feature flags](https://posthog.com/docs/user-guides/feature-flags), which help you to incrementally roll out new features and key an eye on adoption progress. If something isn’t working, you can roll it back instantly. 
+If users are paying for features they don’t use then it lowers the perceived value, so it’s essential to keep an eye on what isn’t working and rollback where necessary. That’s why PostHog offers tools like [feature flags](https://posthog.com/docs/feature-flags/tutorials), which help you to incrementally roll out new features and key an eye on adoption progress. If something isn’t working, you can roll it back instantly. 
 
 [Flagging the use of specific features as a key event](https://posthog.com/docs/user-guides/events) per user type will also help you to track adoption.whether you’re successfully reaching the users they were intended for.
 

contents/docs/experiments/adding-experiment-code.mdx

@@ -140,9 +140,18 @@ if variant == "variant-name" {
     // Do something
 }
 ```
+
+```elixir
+{:ok, feature_flag} = PostHog.feature_flag("experiment-feature-flag-key", "user_distinct_id")
+
+if feature_flag.enabled == "variant-name" do
+    # Do something
+end
+```
+
 </MultiLanguage>
 
-> Since feature flags are not supported yet in our Java, Rust, and Elixir SDKs, to run an experiment using these SDKs see our docs on [how to run experiments without feature flags](/docs/experiments/running-experiments-without-feature-flags). This also applies to running experiments using our API.
+> Since feature flags are not supported yet in our Java and Rust SDKs, to run an experiment using these SDKs see our docs on [how to run experiments without feature flags](/docs/experiments/running-experiments-without-feature-flags). This also applies to running experiments using our API.
 
 ## Step 2 (server-side only): Add the feature flag to your events 
 

contents/docs/experiments/installation.mdx

@@ -29,9 +29,10 @@ import GoInstall from '../integrate/_snippets/install-go.mdx'
 import ReactNativeInstall from '../integrate/_snippets/install-react-native.mdx'
 import AndroidInstall from '../integrate/_snippets/install-android.mdx'
 import IOSInstall from '../integrate/_snippets/install-ios.mdx'
+import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
 
 <!-- prettier-ignore -->
-<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS']}>
+<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Java', 'Rust', 'Elixir', 'api']}>
     <Tab.List>
         <Tab>Web</Tab>
         <Tab>React</Tab>
@@ -90,9 +91,7 @@ import IOSInstall from '../integrate/_snippets/install-ios.mdx'
             </blockquote>
         </Tab.Panel>
         <Tab.Panel>
-            <blockquote class='warning-note'>
-                Since feature flags are not supported yet in our <a href="/docs/libraries/elixir">Elixir SDK</a>, see our docs on <a href="/docs/experiments/running-experiments-without-feature-flags">how to run experiments without feature flags</a>. 
-            </blockquote>
+            <ElixirInstall />
         </Tab.Panel>
         <Tab.Panel>
             <blockquote class='warning-note'>

contents/docs/feature-flags/adding-feature-flag-code.mdx

@@ -24,6 +24,7 @@ import ReactNativeFeatureFlagsCode from '../integrate/feature-flags-code/_snippe
 import AndroidFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-android.mdx'
 import IOSFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-ios.mdx'
 import FlutterFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-flutter.mdx'
+import ElixirFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-elixir.mdx'
 
 <!-- prettier-ignore -->
 <Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Flutter', 'Java', 'Rust', 'Elixir', 'api']}>
@@ -89,9 +90,7 @@ import FlutterFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/f
             </blockquote>
         </Tab.Panel>
         <Tab.Panel>
-            <blockquote class='warning-note'>
-                Feature flags are not supported yet in our <a href="/docs/libraries/elixir">Elixir SDK</a>. However, you can integrate them into your project by using the <a href="/docs/feature-flags/adding-feature-flag-code?tab=api">PostHog API</a>.
-            </blockquote>
+            <ElixirFeatureFlagsCode />
         </Tab.Panel>
         <Tab.Panel>
             <APIFeatureFlagsCode />

contents/docs/feature-flags/installation.mdx

@@ -33,7 +33,7 @@ import FlutterInstall from '../integrate/_snippets/install-flutter.mdx'
 import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
 
 <!-- prettier-ignore -->
-<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Java', 'Rust', 'Elixir', 'Flutter', 'api']}>
+<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Java', 'Rust', 'Flutter', 'Elixir', 'api']}>
     <Tab.List>
         <Tab>Web</Tab>
         <Tab>React</Tab>
@@ -47,8 +47,8 @@ import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
         <Tab>iOS</Tab>
         <Tab>Java</Tab>
         <Tab>Rust</Tab>
-        <Tab>Elixir</Tab>
         <Tab>Flutter</Tab>
+        <Tab>Elixir</Tab>
         <Tab>API</Tab>
     </Tab.List>
     <Tab.Panels>
@@ -93,12 +93,10 @@ import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
             </blockquote>
         </Tab.Panel>
         <Tab.Panel>
-            <blockquote class='warning-note'>
-                Feature flags are not supported yet in our <a href="/docs/libraries/elixir">Elixir SDK</a>. However, you can integrate them into your project by using the <a href="/docs/feature-flags/installation?tab=api">PostHog API</a>.
-            </blockquote>
+           <FlutterInstall />
         </Tab.Panel>
         <Tab.Panel>
-           <FlutterInstall />
+            <ElixirInstall />
         </Tab.Panel>
         <Tab.Panel>
             <APIInstall />

contents/docs/integrate/feature-flags-code/_snippets/feature-flags-code-elixir.mdx

@@ -0,0 +1,42 @@
+Elixir supports a subset of what our [feature flag API](/docs/api/decide) provides.
+
+#### Boolean feature flags
+
+```elixir
+is_my_flag_enabled = Posthog.feature_flag_enabled?("flag-key", "distinct_id_of_your_user")
+
+if is_my_flag_enabled
+    # Do something differently for this user
+    # Optional: fetch the payload
+    {:ok, feature_flag} = Posthog.feature_flag("flag-key", "distinct_id_of_your_user")
+end
+```
+
+#### Multivariate feature flags
+
+```elixir
+{:ok, feature_flag} = Posthog.feature_flag("flag-key", "distinct_id_of_your_user")
+#  %Posthog.FeatureFlag{ name: "flag-key", value: %{"variant-1" => "value-1", "variant-2" => "value-2"}, enabled: "variant-2" }
+
+if feature_flag.enabled == 'variant-2' # replace 'variant-2' with the key of your variant
+    # Do something differently for this user
+end
+```
+
+#### Fetching all feature flags
+
+```elixir
+Posthog.feature_flags("distinct_id_of_your_user")
+
+{:ok,
+ %{
+   "featureFlagPayloads" => %{
+     "feature-1" => 1,
+     "feature-2" => %{"variant-1" => "value-1", "variant-2" => "value-2"}
+   },
+   "featureFlags" => %{"feature-1" => true, "feature-2" => "variant-2"}
+ }}
+
+```
+
+More documentation can be found in the [repository](https://github.com/nkezhaya/posthog).

contents/docs/libraries/elixir/index.mdx

@@ -11,7 +11,7 @@ icon: >-
 features:
   eventCapture: true
   userIdentification: true
-  featureFlags: false
+  featureFlags: true
   groupAnalytics: true
   surveys: false
   llmObservability: false
@@ -38,7 +38,9 @@ import FeatureFlagsLibsIntro from "../_snippets/feature-flags-libs-intro.mdx"
 
 <FeatureFlagsLibsIntro />
 
-Feature flags are not supported yet in our Elixir SDK. However, you can integrate them into your project by using the [PostHog API](/docs/feature-flags/adding-feature-flag-code?tab=api).
+import ElixirFeatureFlagsCode from '../../integrate/feature-flags-code/_snippets/feature-flags-code-elixir.mdx'
+
+<ElixirFeatureFlagsCode />
 
 ## Thanks
 

src/components/LibraryFeatures/index.tsx

@@ -9,16 +9,20 @@ const features = [
     {
         key: 'autoCapture',
         name: 'Autocapture',
-        url: 'https://posthog.com/docs/data/autocapture',
+        url: 'https://posthog.com/docs/product-analytics/autocapture',
     },
     {
         key: 'userIdentification',
         name: 'User identification',
-        url: 'https://posthog.com/docs/integrate/identifying-users',
+        url: 'https://posthog.com/docs/product-analytics/identify',
+    },
+    { key: 'sessionRecording', name: 'Session replay', url: 'https://posthog.com/docs/session-replay' },
+    { key: 'featureFlags', name: 'Feature flags', url: 'https://posthog.com/docs/feature-flags' },
+    {
+        key: 'groupAnalytics',
+        name: 'Group analytics',
+        url: 'https://posthog.com/docs/product-analytics/group-analytics',
     },
-    { key: 'sessionRecording', name: 'Session replay', url: 'https://posthog.com/docs/user-guides/recordings' },
-    { key: 'featureFlags', name: 'Feature flags', url: 'https://posthog.com/docs/user-guides/feature-flags' },
-    { key: 'groupAnalytics', name: 'Group analytics', url: 'https://posthog.com/docs/user-guides/group-analytics' },
     { key: 'surveys', name: 'Surveys', url: 'https://posthog.com/docs/surveys' },
     {
         key: 'llmObservability',
@@ -29,7 +33,7 @@ const features = [
 ] as const
 
 export type LibraryFeaturesProps = {
-    availability?: Record<typeof features[number]['key'], boolean>
+    availability?: Record<(typeof features)[number]['key'], boolean>
 }
 
 export const LibraryFeatures = ({ availability }: LibraryFeaturesProps) => {

src/navs/index.js

@@ -1300,6 +1300,9 @@ export const docsMenu = {
                         {
                             name: 'Elixir',
                             url: '/docs/libraries/elixir',
+                            badge: {
+                                title: '3rd party',
+                            },
                         },
                         {
                             name: 'Flutter',

vercel.json

@@ -128,7 +128,6 @@
         { "source": "/docs/features/cohorts", "destination": "/docs/user-guides/cohorts" },
         { "source": "/docs/features/dashboards", "destination": "/docs/user-guides/dashboards" },
         { "source": "/docs/features/events", "destination": "/docs/user-guides/events" },
-        { "source": "/docs/features/feature-flags", "destination": "/docs/user-guides/feature-flags" },
         { "source": "/docs/features/funnels", "destination": "/docs/user-guides/funnels" },
         { "source": "/docs/features/organizations", "destination": "/docs/user-guides/organizations" },
         { "source": "/docs/features/paths", "destination": "/docs/user-guides/paths" },
@@ -676,7 +675,9 @@
         { "source": "/docs/experiments/under-the-hood", "destination": "/docs/experiments/experiment-significance" },
         { "source": "/docs/experiments/significance", "destination": "/docs/experiments/experiment-significance" },
         { "source": "/docs/session-replay/manual", "destination": "/docs/session-replay/installation" },
-        { "source": "/docs/user-guides/feature-flags", "destination": "/docs/feature-flags/manual" },
+        { "source": "/docs/features/feature-flags", "destination": "/docs/feature-flags" },
+        { "source": "/docs/user-guides/feature-flags", "destination": "/docs/feature-flags" },
+        { "source": "/docs/feature-flags/manual", "destination": "/docs/feature-flags" },
         { "source": "/manual/group-analytics", "destination": "/docs/product-analytics/group-analytics" },
         { "source": "/docs/product-analytics/hogql", "destination": "/docs/hogql" },
         { "source": "/docs/hogql/guide", "destination": "/docs/product-analytics/sql" },