Improved dev environment (#2211)

* Improved dev env setup

* Cleanup duplicate checks

* Applied PR feedback

* Updated go.mod/go.sum

* go mod tidy

* Update .devcontainer/devcontainer.json

* Update pkg/http/server_test.go

Co-authored-by: Jan Larwig <jan@larwig.com>

* Create launch.json

* Update .devcontainer/Dockerfile

* Apply suggestions from code review

---------

Co-authored-by: Jan Larwig <jan@larwig.com>

.devcontainer/Dockerfile

@@ -0,0 +1,14 @@
+FROM mcr.microsoft.com/vscode/devcontainers/go:0-1.19
+
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+    pre-commit \
+    vim \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* \
+    && mkdir -p /go/pkg \
+    && chmod -R a+w /go/pkg
+
+WORKDIR /workspace

.devcontainer/devcontainer.json

@@ -0,0 +1,45 @@
+{
+  "name": "oauth2-proxy Dev",
+  "context": "..",
+  "dockerFile": "./Dockerfile",
+  "postCreateCommand": "pre-commit install && go mod download",
+  "containerEnv": { "DEVCONTAINER": "1" },
+  "appPort": ["4180:4180"],
+  "runArgs": ["-e", "GIT_EDITOR=code --wait"],
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "golang.go",
+        "ms-vscode.makefile-tools",
+        "visualstudioexptteam.vscodeintellicode",
+        "redhat.vscode-yaml",
+        "esbenp.prettier-vscode",
+        "GitHub.vscode-pull-request-github"
+      ],
+      "settings": {
+        "editor.formatOnPaste": false,
+        "editor.formatOnSave": true,
+        "editor.formatOnType": true,
+        "files.trimTrailingWhitespace": true,
+        "yaml.customTags": [
+          "!input scalar",
+          "!secret scalar",
+          "!include_dir_named scalar",
+          "!include_dir_list scalar",
+          "!include_dir_merge_list scalar",
+          "!include_dir_merge_named scalar"
+        ]
+      }
+    }
+  },
+  "features": {
+    "ghcr.io/devcontainers/features/docker-in-docker": {},
+    "ghcr.io/devcontainers/features/common-utils": {
+      "configureZshAsDefaultShell": true,
+      "username": "vscode",
+      "userUid": 1000,
+      "userGid": 1000
+    },
+    "ghcr.io/devcontainers/features/kubectl-helm-minikube": {}
+  }
+}