feat: Synth optional de-identified telemetry

* Added telemetry

* Added interactive prompt for telemetry install

* Bumped version to 0.4.5

GitOrigin-RevId: 0380a0ce71443db423941f46bbca0afb1cef48a3

default.nix

@@ -16,7 +16,7 @@
 , release ? true
 }:
 let
-  version = "0.4.4";
+  version = "0.4.5";
   darwinBuildInputs =
     stdenv.lib.optionals stdenv.hostPlatform.isDarwin (with darwin.apple_sdk.frameworks; [
       libiconv

docs/docs/other/telemetry.md

@@ -0,0 +1,85 @@
+---
+title: Telemetry
+---
+
+Synth collects de-identified usage data to help create a better product and user experience.
+
+Synth telemetry is **opt-in**; the user is explicity prompted at installation, asking if they would like to participate
+in de-identified data collection.
+
+## Philosophy
+
+Below are a set of principles that guide the telemetry decisions made in Synth:
+
+1. It is made *completely transparent* that telemetry is going to be installed
+2. It is made *completely transparent* as to what data we collect
+3. No personally identifiable information is collected. (IP addresses are discarded at the Sink)
+4. Nothing is collected unless the user explicitly opts-in.
+
+## Enabling / Disabling Telemetry
+
+Synth uses a configuration file under the user configuration directory (e.g. `~/.config/synth/config.json` on typical unix systems) as a marker for telemetry being enabled. This file
+also contains the user's randomly generated unique `distinct_id`.
+
+The user is prompted during the installation process about telemetry being enabled.
+
+Users can check if telemetry is enabled by running `synth telemetry status`.
+
+Users can opt-out at any time by running `synth telemetry disable`.
+
+## Where does the data go?
+
+All the telemetry data is collected in a [Posthog](https://posthog.com/) instance run by the maintainers of Synth.
+
+If for whatever reason you would like the data associated with your UUID to be deleted, please contact `[email protected]`.
+
+## What does Synth collect?
+
+Synth's telemetry collects 6 fields:
+
+- `distinct_id`: A randomly generated UUID stored at `~/.config/synth/config.json`
+- `command`: The command that was issued by the user. One
+  of (`init | import | generate | telemetry::enabled | telemetry::disabled`)
+- `success`: If the command issued succeeded or failed.
+- `version`: The version of Synth being used. For example `v0.4.3`.
+- `os`: The host operating system, for example 'linux'
+- `timestamp`: The time at which the command was issued. For example `2021-05-06T16:13:40.084Z`.
+
+Below is a Synth schema generates telemetry events:
+
+```json synth
+{
+    "type": "object",
+    "distinct_id": {
+        "type": "string",
+        "uuid": {}
+    },
+    "command": {
+        "type": "string",
+        "categorical": {
+            "import": 1,
+            "generate": 10
+        }
+    },
+    "version": {
+        "type": "string",
+        "pattern": "v0\\.4\\.3"
+    },
+    "os": {
+        "type": "string",
+        "categorical": {
+            "linux": 10,
+            "mac os": 1
+        }
+    },
+    "timestamp": {
+      "type": "string",
+      "date_time": {
+        "format": "%Y-%m-%dT%H:%M:%S",
+        "subtype": "naive_date_time",
+        "begin": "2015-01-01T00:00:00",
+        "end": "2020-01-01T12:00:00"
+      }
+    }
+}
+```