Adding endpoint to upload android map files (#161252)

## Summary

We need a way to decode Android crash's stacktraces so that they can
provide meaningful insights to our customers, this is because, due to
security reasons, android apps tend to obfuscate their code before
publishing it online, making crash reports contain obfuscated names,
which don't make any sense before mapping them to the actual source code
names.

In order to help our customers deobfuscate their stacktraces, we need to
allow them to provide us with an R8 map file, which is generated by the
code obfuscation tool (R8) at compile time. This map file is needed to
later do the deobfuscation process.

So these code changes take care of adding a new endpoint that our
customers can use to upload their map files, similarly to what's
currently available to [RUM
Sourcemaps](https://www.elastic.co/guide/en/apm/guide/current/source-map-how-to.html#source-map-rum-upload),
the Android map files will be uploaded to ES, using the same index as
the one currently used to store RUM Sourcemaps.

There's a couple of reasons why a new endpoint to upload android maps is
needed instead of re-using the existing RUM Sourcemaps one:
* The Sourcemaps upload endpoint has validations in place to check the
sourcemap format, which must be a JSON with some expected keys
available. Android map files don't have a JSON format, so they are
rejected by the sourcemaps endpoint.
* Android map files tend to be large in size, just as an example, the
map file generated for our [sample
app](https://github.com/elastic/opbeans-android) has a size of ~7 MB, so
for real apps this number can be larger, which would also cause issues
with the RUM upload endpoint since it has a max file limit size of 1 MB.
* The RUM upload endpoint contains a parameter (`bundle_filepath `) that
doesn't have an equivalent for the android map use case.

This PR depends on elastic/kibana#161152

### Checklist

Delete any items that are not applicable to this PR.

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

---------

Co-authored-by: kibanamachine <[email protected]>
Co-authored-by: Søren Louv-Jansen <[email protected]>
Co-authored-by: Brandon Morelli <[email protected]>
Co-authored-by: Katerina Patticha <[email protected]>

Author: 5 people

api.asciidoc

@@ -11,6 +11,7 @@ Some APM app features are provided via a REST API:
 * <<agent-config-api>>
 * <<apm-annotation-api>>
 * <<rum-sourcemap-api>>
+* <<android-sourcemap-api>>
 * <<agent-key-api>>
 
 [float]
@@ -715,6 +716,219 @@ curl -X DELETE "http://localhost:5601/api/apm/sourcemaps/apm:foo-1.0.0-644fd5a9"
 *******************************************************
 ////
 
+[role="xpack"]
+[[android-sourcemap-api]]
+=== Android source map API
+
+IMPORTANT: This endpoint is only compatible with the
+{apm-guide-ref}/index.html[APM integration for Elastic Agent].
+
+An Android source map (generated using Android's https://developer.android.com/build/shrink-code[R8 tool])
+allows obfuscated app stacktraces to be mapped back to original source code --
+allowing you to maintain the size and security of minimized code, without losing the ability to debug your application.
+
+For best results, uploading source maps should become a part of your deployment procedure,
+and not something you only do when you see unhelpful errors.
+That’s because uploading source maps after errors happen won’t make old errors magically readable --
+errors must occur again for source mapping to occur.
+
+The following APIs are available:
+
+* <<android-sourcemap-post>>
+* <<android-sourcemap-get>>
+* <<android-sourcemap-delete>>
+
+[float]
+[[use-android-sourcemap-api]]
+==== How to use APM APIs
+
+.Expand for required headers, privileges, and usage details
+[%collapsible%closed]
+======
+include::api.asciidoc[tag=using-the-APIs]
+======
+
+////
+*******************************************************
+////
+
+[[android-sourcemap-post]]
+==== Create or update an Android source map
+
+Create or update an Android source map for a specific app and version.
+
+[[android-sourcemap-post-privs]]
+===== Privileges
+
+The user accessing this endpoint requires `All` Kibana privileges for the {beat_kib_app} feature.
+For more information, see <<kibana-privileges>>.
+
+[[android-sourcemap-post-req]]
+===== Request
+
+`POST /api/apm/androidmaps`
+
+[role="child_attributes"]
+[[android-sourcemap-post-req-body]]
+===== Request body
+
+`service_name`::
+(required, string) The name of the Android app that the map should apply to.
+
+`service_version`::
+(required, string) The version of the Android app that the map should apply to.
+
+`map_file`::
+(required, string or file upload) The R8-generated map.
+
+[[android-sourcemap-post-example]]
+===== Examples
+
+The following example uploads a source map for a app named `foo` and a service version of `1.0.0`:
+
+[source,curl]
+--------------------------------------------------
+curl -X POST "http://localhost:5601/api/apm/androidmaps" \
+-H 'Content-Type: multipart/form-data' \
+-H 'kbn-xsrf: true' \
+-H 'Authorization: ApiKey ${YOUR_API_KEY}' \
+-F 'service_name="foo"' \
+-F 'service_version="1.0.0"' \
+-F 'map_file=@"/Path/to/the/file/mapping.txt"'
+--------------------------------------------------
+
+[[android-sourcemap-post-body]]
+===== Response body
+
+[source,js]
+--------------------------------------------------
+{
+  "type": "sourcemap",
+  "identifier": "foo-1.0.0-android",
+  "relative_url": "/api/fleet/artifacts/foo-1.0.0-android/644fd5a997d1ddd90ee131ba18e2b3d03931d89dd1fe4599143c0b3264b3e456",
+  "body": "eJyFkL1OwzAUhd/Fc+MbYMuCEBIbHRjKgBgc96R16tiWr1OQqr47NwqJxEK3q/PzWccXxchnZ7E1A1SjuhjVZtF2yOxiEPlO17oWox3D3uPFeSRTjmJQARfCPeiAgGx8NTKsYdAc1T3rwaSJGcds8Sp3c1HnhfywUZ3QhMTFFGepZxqMC9oex3CS9tpk1XyozgOlmoVKuJX1DqEQZ0su7PGtLU+V/3JPKc3cL7TJ2FNDRPov4bFta3MDM4f7W69lpJjLO9qdK8bzVPhcJz3HUCQ4LbO/p5hCSC4cZPByrp/wFqOklbpefwAhzpqI",
+  "created": "2021-07-09T20:47:44.812Z",
+  "id": "apm:foo-1.0.0-android-644fd5a997d1ddd90ee131ba18e2b3d03931d89dd1fe4599143c0b3264b3e456",
+  "compressionAlgorithm": "zlib",
+  "decodedSha256": "644fd5a997d1ddd90ee131ba18e2b3d03931d89dd1fe4599143c0b3264b3e456",
+  "decodedSize": 441,
+  "encodedSha256": "024c72749c3e3dd411b103f7040ae62633558608f480bce4b108cf5b2275bd24",
+  "encodedSize": 237,
+  "encryptionAlgorithm": "none",
+  "packageName": "apm"
+}
+--------------------------------------------------
+
+////
+*******************************************************
+////
+
+[[android-sourcemap-get]]
+==== Get source maps
+
+Returns an array of Fleet artifacts, including source map uploads.
+
+[[android-sourcemap-get-privs]]
+===== Privileges
+
+The user accessing this endpoint requires `Read` or `All` Kibana privileges for the {beat_kib_app} feature.
+For more information, see <<kibana-privileges>>.
+
+[[android-sourcemap-get-req]]
+===== Request
+
+`GET /api/apm/sourcemaps`
+
+[[android-sourcemap-get-example]]
+===== Example
+
+The following example requests all uploaded source maps:
+
+[source,curl]
+--------------------------------------------------
+curl -X GET "http://localhost:5601/api/apm/sourcemaps" \
+-H 'Content-Type: application/json' \
+-H 'kbn-xsrf: true' \
+-H 'Authorization: ApiKey ${YOUR_API_KEY}'
+--------------------------------------------------
+
+[[android-sourcemap-get-body]]
+===== Response body
+
+[source,js]
+--------------------------------------------------
+{
+  "artifacts": [
+    {
+      "type": "sourcemap",
+      "identifier": "foo-1.0.0-android",
+      "relative_url": "/api/fleet/artifacts/foo-1.0.0-android/644fd5a997d1ddd90ee131ba18e2b3d03931d89dd1fe4599143c0b3264b3e456",
+      "body": {
+        "serviceName": "foo",
+        "serviceVersion": "1.0.0",
+        "bundleFilepath": "android",
+        "sourceMap": "# compiler: R8\n# compiler_version: 3.2.47\n# min_api: 26\n..."
+      },
+      "created": "2021-07-09T20:47:44.812Z",
+      "id": "apm:foo-1.0.0-android-644fd5a997d1ddd90ee131ba18e2b3d03931d89dd1fe4599143c0b3264b3e456",
+      "compressionAlgorithm": "zlib",
+      "decodedSha256": "644fd5a997d1ddd90ee131ba18e2b3d03931d89dd1fe4599143c0b3264b3e456",
+      "decodedSize": 441,
+      "encodedSha256": "024c72749c3e3dd411b103f7040ae62633558608f480bce4b108cf5b2275bd24",
+      "encodedSize": 237,
+      "encryptionAlgorithm": "none",
+      "packageName": "apm"
+    }
+  ]
+}
+--------------------------------------------------
+
+////
+*******************************************************
+////
+
+[[android-sourcemap-delete]]
+==== Delete source map
+
+Delete a previously uploaded source map.
+
+[[android-sourcemap-delete-privs]]
+===== Privileges
+
+The user accessing this endpoint requires `All` Kibana privileges for the {beat_kib_app} feature.
+For more information, see <<kibana-privileges>>.
+
+[[android-sourcemap-delete-req]]
+===== Request
+
+`DELETE /api/apm/sourcemaps/:id`
+
+[[android-sourcemap-delete-example]]
+===== Example
+
+The following example deletes a source map with an id of `apm:foo-1.0.0-android-644fd5a9`:
+
+[source,curl]
+--------------------------------------------------
+curl -X DELETE "http://localhost:5601/api/apm/sourcemaps/apm:foo-1.0.0-android-644fd5a9" \
+-H 'Content-Type: application/json' \
+-H 'kbn-xsrf: true' \
+-H 'Authorization: ApiKey ${YOUR_API_KEY}'
+--------------------------------------------------
+
+[[android-sourcemap-delete-body]]
+===== Response body
+
+[source,js]
+--------------------------------------------------
+{}
+--------------------------------------------------
+
+////
+*******************************************************
+*******************************************************
+////
+
 [role="xpack"]
 [[agent-key-api]]
 === APM agent Key API