Bug 1697602 Remove AET support

Marking as a draft, because we'll need to think through sequencing.
We can't merge this until we change ops logic to remove AET-specific jobs.

We'll also need to consider what to do about the few messages still coming in
from old builds of Firefox Nightly that have AET enabled.

GRAVEYARD.md

@@ -1,5 +1,11 @@
 # Link to code removed from this repository
 
+- 2021-03-12 (available until [commit `c05fbab`](https://github.com/mozilla/gcp-ingestion/commit/c05fbabcb44c5a8a290be311a87951728cf587b6))
+  - Remove support for Account Ecosystem Telemetry (AET);
+    see [Bug 1697602](https://bugzilla.mozilla.org/show_bug.cgi?id=1697602)
+  - Also removes `ParseLogEntry` which transforms a Google Cloud Logging
+    (Stackdriver) `LogEntry` message into one compatible with structured
+    ingestion, which could be relevant for future use cases.
 - 2020-06-01 (available until [commit `f1d6464`](https://github.com/mozilla/gcp-ingestion/commit/f1d646442b8c1fcd63202ebca91363979b5b2ae2))
   - Remove `DeduplicateByDocumentId` transform, which was intended for use with
     the backfill from `heka` data, but did not perform well and was never used

ingestion-beam/src/main/java/com/mozilla/telemetry/Decoder.java

@@ -1,6 +1,5 @@
 package com.mozilla.telemetry;
 
-import com.mozilla.telemetry.aet.AetProcessing;
 import com.mozilla.telemetry.decoder.AddMetadata;
 import com.mozilla.telemetry.decoder.DecoderOptions;
 import com.mozilla.telemetry.decoder.DecryptPioneerPayloads;
@@ -68,11 +67,6 @@ public static PipelineResult run(DecoderOptions.Parsed options) {
             .apply(GeoCityLookup.of(options.getGeoCityDatabase(), options.getGeoCityFilter())) //
             .apply(DecompressPayload.enabled(options.getDecompressInputPayloads())))
 
-        // Special case: decryption of Account Ecosystem Telemetry identifiers
-        .map(p -> options.getAetEnabled() ? p //
-            .apply(AetProcessing.of(options)).failuresTo(failureCollections) //
-            : p)
-
         // URI Parsing
         .map(p -> p //
             .apply("ParseUri", ParseUri.of()).failuresTo(failureCollections))