Merge branch '8-improve-ci' into 'master'

Improve CI

Closes #8.

- change image to `bitwalker/alpine-elixir:1.10.4`
- 5 stages, 2 sequences in parallel: 1 cache for dev, 1 for test
- 2 artifacts for reports
- 1 artifact for dialyzer PLT (cache as artifact so that it still caches on fail)

See merge request !9

.dialyzer_ignore.exs

+[]

.gitlab-ci.yml

 stages:
-  - static_analysis
-  - deploy
+  - setup
+  - test
+  - format
+  - credo
+  - dialyzer
+  - docs
 
-image: elixir:latest
+image: bitwalker/alpine-elixir:1.10.4
 
-before_script:
-  - mix local.rebar --force
-  - mix local.hex --force
-  - mix deps.get
+cache: &global_cache
+  key: cache-test
+  when: always
+  policy: pull
+  paths:
+    - _build
+    - deps
+
+variables:
+  MIX_ENV: test
+
+
+prepare_test:
+  stage: setup
+  script:
+    - mix deps.get
+    - mix compile
+  cache:
+    <<: *global_cache
+    policy: pull-push
 
 test:
-  stage: static_analysis
+  stage: test
+  needs:
+    - prepare_test
   services:
     - postgres:latest
   variables:
@@ -19,10 +41,11 @@ test:
     POSTGRES_PASSWORD: postgres
     POSTGRES_HOST: postgres
     POSTGRES_HOST_AUTH_METHOD: trust
+    MIX_ENV: test
+  before_script:
+    - mix ecto.create
+    - mix ecto.migrate
   script:
-    - MIX_ENV=test mix compile
-    - MIX_ENV=test mix ecto.create
-    - MIX_ENV=test mix ecto.migrate
     - mix test --cover
   artifacts:
     when: always
@@ -33,16 +56,70 @@ test:
       cobertura: coverage.xml
 
 format:
-  stage: static_analysis
+  stage: format
+  needs:
+    - prepare_test
   script:
     - mix format --check-formatted
 
-pages:
-  stage: deploy
+credo:
+  stage: credo
+  needs:
+    - prepare_test
   script:
-  - mix docs -o public
+    - mix credo suggest --only readability | tee credo.log
   artifacts:
+    when: always
     paths:
-    - public
+      - "credo.log"
+
+## this should be uncommented when
+## https://gitlab.com/gitlab-org/gitlab-runner/-/issues/27172
+## is fixed
+# dialyzer:
+#   stage: dialyzer
+#   needs:
+#     - prepare_test
+#   script:
+#     - mix dialyzer
+#   cache: 
+#     <<: *global_cache
+#     policy: pull-push
+#     paths:
+#       - _build
+#       - deps
+#       - priv/plts
+
+
+# Doc generation
+
+prepare_dev:
+  stage: setup
   only:
-  - master
+    - master
+  variables:
+    MIX_ENV: test
+  script:
+    - mix deps.get
+    - mix compile
+  cache:
+    <<: *global_cache
+    policy: pull-push
+    key: cache-dev
+
+pages:
+  stage: docs
+  only:
+    - master
+  needs:
+    - prepare_dev
+  variables:
+    MIX_ENV: dev
+  script:
+    - mix docs -o public
+  cache:
+    <<: *global_cache
+    key: cache-dev
+  artifacts:
+    paths:
+      - public

lib/matrix_app_service/application.ex

@@ -49,15 +49,15 @@ defmodule MatrixAppService.Application do
     :ok
   end
 
-  def start_endpoint?() do
+  def start_endpoint? do
     Application.get_env(:matrix_app_service, :internal_supervisor, false)
   end
 
-  def start_repo?() do
+  def start_repo? do
     Application.get_env(:matrix_app_service, :internal_repo, false)
   end
 
-  def endpoint_config() do
+  def endpoint_config do
     [
       transaction_adapter: Application.fetch_env!(:matrix_app_service, :transaction_adapter),
       room_adapter: Application.fetch_env!(:matrix_app_service, :room_adapter),

lib/matrix_app_service/bridge.ex

 defmodule MatrixAppService.Bridge do
+  @moduledoc """
+  This module is used when the library uses its own repo. 
+  """
+
   use MatrixAppService.BridgeConfig, repo: MatrixAppService.Repo
 end

lib/matrix_app_service/bridge/room.ex

 defmodule MatrixAppService.Bridge.Room do
+  @moduledoc """
+  Schema and helpers for keeping track of room correspondence. 
+  """
+
   use Ecto.Schema
   import Ecto.Changeset
 

lib/matrix_app_service/bridge/user.ex

 defmodule MatrixAppService.Bridge.User do
+  @moduledoc """
+  Schema and helpers for keeping track of user correspondence. 
+  """
+
   use Ecto.Schema
   import Ecto.Changeset
 

lib/matrix_app_service/migrations.ex

 defmodule MatrixAppService.Migrations do
+  @moduledoc """
+  Module containing migrations for tables used in bridge mode. Should be used like this:
+
+  TODO: example
+  """
+
   use Ecto.Migration
 
   def change do

lib/matrix_app_service_web/auth_plug.ex

@@ -17,11 +17,13 @@ defmodule MatrixAppServiceWeb.AuthPlug do
 
   @doc false
   @impl Plug
-  def call(%Plug.Conn{params: %{"access_token" => access_token}} = conn, homeserver_token) when is_binary(homeserver_token) do
+  def call(%Plug.Conn{params: %{"access_token" => access_token}} = conn, homeserver_token)
+      when is_binary(homeserver_token) do
     verify_access_token(conn, homeserver_token)
   end
 
-  def call(%Plug.Conn{params: %{"access_token" => access_token}} = conn, homeserver_token) when is_function(homeserver_token, 0) do
+  def call(%Plug.Conn{params: %{"access_token" => access_token}} = conn, homeserver_token)
+      when is_function(homeserver_token, 0) do
     verify_access_token(conn, homeserver_token.())
   end
 

lib/matrix_app_service_web/set_config_plug.ex

 defmodule MatrixAppServiceWeb.SetConfigPlug do
   @moduledoc """
+  This plug allows to set compile time configuration as private conn parameters.
   """
 
   @behaviour Plug

mix.exs

@@ -17,7 +17,13 @@ defmodule MatrixAppService.MixProject do
       aliases: aliases(),
       deps: deps(),
       docs: [main: "MatrixAppService"],
-      test_coverage: test_coverage(System.get_env("CI"))
+      test_coverage: test_coverage(System.get_env("CI")),
+
+      # elixirc_options: [warnings_as_errors: true],
+      dialyzer: [
+        plt_file: {:no_warn, "priv/plts/dialyzer.plt"},
+        ignore_warnings: ".dialyzer_ignore.exs"
+      ]
     ]
   end
 
@@ -65,7 +71,9 @@ defmodule MatrixAppService.MixProject do
       {:ex_doc, "~> 0.22", only: :dev, runtime: false},
       {:junit_formatter, "~> 3.1", only: :test},
       {:cobertura_cover, "~> 0.9.0", only: :test},
-      {:postgrex, ">= 0.0.0", only: :test}
+      {:postgrex, ">= 0.0.0", only: :test},
+      {:credo, "~> 1.4.1", only: [:dev, :test], runtime: false},
+      {:dialyxir, "~> 1.0.0", only: [:dev, :test], runtime: false}
     ]
   end
 

mix.lock

 %{
+  "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm", "7af5c7e09fe1d40f76c8e4f9dd2be7cebd83909f31fee7cd0e9eadc567da8353"},
   "certifi": {:hex, :certifi, "2.5.2", "b7cfeae9d2ed395695dd8201c57a2d019c0c43ecaf8b8bcb9320b40d6662f340", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm", "3b3b5f36493004ac3455966991eaf6e768ce9884693d9968055aeeeb1e575040"},
   "cobertura_cover": {:hex, :cobertura_cover, "0.9.0", "01b9c5d2688d68240c1394c931383f8b29105b894ae499ef48aefd082a8a42b3", [:mix], [], "hexpm", "870bc4658cacc5c80d13f1206b688925234d2dc4e00278e8a3e72fbbd6bea0b1"},
   "connection": {:hex, :connection, "1.1.0", "ff2a49c4b75b6fb3e674bfc5536451607270aac754ffd1bdfe175abe4a6d7a68", [:mix], [], "hexpm", "722c1eb0a418fbe91ba7bd59a47e28008a189d47e37e0e7bb85585a016b2869c"},
   "cowboy": {:hex, :cowboy, "2.8.0", "f3dc62e35797ecd9ac1b50db74611193c29815401e53bac9a5c0577bd7bc667d", [:rebar3], [{:cowlib, "~> 2.9.1", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "4643e4fba74ac96d4d152c75803de6fad0b3fa5df354c71afdd6cbeeb15fac8a"},
   "cowboy_telemetry": {:hex, :cowboy_telemetry, "0.3.1", "ebd1a1d7aff97f27c66654e78ece187abdc646992714164380d8a041eda16754", [:rebar3], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "3a6efd3366130eab84ca372cbd4a7d3c3a97bdfcfb4911233b035d117063f0af"},
   "cowlib": {:hex, :cowlib, "2.9.1", "61a6c7c50cf07fdd24b2f45b89500bb93b6686579b069a89f88cb211e1125c78", [:rebar3], [], "hexpm", "e4175dc240a70d996156160891e1c62238ede1729e45740bdd38064dad476170"},
+  "credo": {:hex, :credo, "1.4.1", "16392f1edd2cdb1de9fe4004f5ab0ae612c92e230433968eab00aafd976282fc", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "155f8a2989ad77504de5d8291fa0d41320fdcaa6a1030472e9967f285f8c7692"},
   "db_connection": {:hex, :db_connection, "2.3.1", "4c9f3ed1ef37471cbdd2762d6655be11e38193904d9c5c1c9389f1b891a3088e", [:mix], [{:connection, "~> 1.0", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm", "abaab61780dde30301d840417890bd9f74131041afd02174cf4e10635b3a63f5"},
   "decimal": {:hex, :decimal, "2.0.0", "a78296e617b0f5dd4c6caf57c714431347912ffb1d0842e998e9792b5642d697", [:mix], [], "hexpm", "34666e9c55dea81013e77d9d87370fe6cb6291d1ef32f46a1600230b1d44f577"},
+  "dialyxir": {:hex, :dialyxir, "1.0.0", "6a1fa629f7881a9f5aaf3a78f094b2a51a0357c843871b8bc98824e7342d00a5", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "aeb06588145fac14ca08d8061a142d52753dbc2cf7f0d00fc1013f53f8654654"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.12", "b245e875ec0a311a342320da0551da407d9d2b65d98f7a9597ae078615af3449", [:mix], [], "hexpm", "711e2cc4d64abb7d566d43f54b78f7dc129308a63bc103fbd88550d2174b3160"},
   "ecto": {:hex, :ecto, "3.5.5", "48219a991bb86daba6e38a1e64f8cea540cded58950ff38fbc8163e062281a07", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "98dd0e5e1de7f45beca6130d13116eae675db59adfa055fb79612406acf6f6f1"},
   "ecto_sql": {:hex, :ecto_sql, "3.5.3", "1964df0305538364b97cc4661a2bd2b6c89d803e66e5655e4e55ff1571943efd", [:mix], [{:db_connection, "~> 2.2", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.5.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.3.0 or ~> 0.4.0", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.15.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:tds, "~> 2.1.1", [hex: :tds, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "d2f53592432ce17d3978feb8f43e8dc0705e288b0890caf06d449785f018061c"},
+  "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
   "ex_doc": {:hex, :ex_doc, "0.23.0", "a069bc9b0bf8efe323ecde8c0d62afc13d308b1fa3d228b65bca5cf8703a529d", [:mix], [{:earmark_parser, "~> 1.4.0", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm", "f5e2c4702468b2fd11b10d39416ddadd2fcdd173ba2a0285ebd92c39827a5a16"},
   "hackney": {:hex, :hackney, "1.16.0", "5096ac8e823e3a441477b2d187e30dd3fff1a82991a806b2003845ce72ce2d84", [:rebar3], [{:certifi, "2.5.2", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.1", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.3.0", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.6", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm", "3bf0bebbd5d3092a3543b783bf065165fa5d3ad4b899b836810e513064134e18"},
   "idna": {:hex, :idna, "6.0.1", "1d038fb2e7668ce41fbf681d2c45902e52b3cb9e9c77b55334353b222c2ee50c", [:rebar3], [{:unicode_util_compat, "0.5.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "a02c8a1c4fd601215bb0b0324c8a6986749f807ce35f25449ec9e69758708122"},

test/matrix_app_service/client.ex

 defmodule MatrixAppService.ClientTest do
+  @moduledoc false
+
   use ExUnit.Case
   use Plug.Test
 end

test/support/test_room_adapter.ex

 defmodule MatrixAppService.TestRoomAdapter do
+  @moduledoc false
   @behaviour MatrixAppService.Adapter.Room
 
   @impl MatrixAppService.Adapter.Room

test/support/test_transaction_adapter.ex

 defmodule MatrixAppService.TestTransactionAdapter do
-  require Logger
+  @moduledoc false
   @behaviour MatrixAppService.Adapter.Transaction
+  require Logger
 
   @impl MatrixAppService.Adapter.Transaction
   def new_event(%MatrixAppService.Event{}) do

test/support/test_user_adapter.ex

 defmodule MatrixAppService.TestUserAdapter do
+  @moduledoc false
   @behaviour MatrixAppService.Adapter.User
 
   @impl MatrixAppService.Adapter.User