refactor: switch to OpenAPITools's generator for our HTTP clients (#33)

* build: add CI job to check OpenAPI generation is clean
* feat: add hidden flag for HTTP debug

etc/checkopenapi.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -e
+
+declare -r ETC_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" &> /dev/null && pwd)"
+${ETC_DIR}/generate-openapi.sh
+
+if ! git --no-pager diff --exit-code -- internal/api; then
+  >&2 echo "openapi generated client doesn't match spec, please run 'make openapi'"
+  exit 1
+fi

etc/generate-openapi.sh

@@ -0,0 +1,66 @@
+#!/usr/bin/env bash
+
+declare -r ETC_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" &> /dev/null && pwd)"
+declare -r ROOT_DIR="$(dirname ${ETC_DIR})"
+
+declare -r GENERATOR_DOCKER_IMG=openapitools/openapi-generator-cli:v5.1.0
+
+# Run the generator - This produces many more files than we want to track in git.
+docker run --rm -it -u "$(id -u):$(id -g)" \
+  -v "${ROOT_DIR}":/influx \
+  ${GENERATOR_DOCKER_IMG} \
+  generate \
+  -g go \
+  -i /influx/internal/api/api.yml \
+  -o /influx/internal/api \
+  --additional-properties packageName=api,enumClassPrefix=true,generateInterfaces=true
+
+# Clean up files we don't care about.
+(
+  cd "${ROOT_DIR}/internal/api"
+  rm -rf go.mod go.sum git_push.sh api docs .openapi-generator .travis.yml .gitignore
+)
+
+# Edit the generated files.
+(
+  cd "${ROOT_DIR}"
+
+  # Inject linter directives into generated files to make staticcheck happy.
+  cat <<EOF > internal/api/client.go
+//lint:file-ignore ST1005 Ignore capitalized errors, they're generated
+//lint:file-ignore SA6005 Ignore old-fashioned way of comparing strings, it's generated
+
+$(cat internal/api/client.go)
+EOF
+  cat <<EOF > internal/api/configuration.go
+//lint:file-ignore ST1005 Ignore capitalized errors, they're generated
+
+$(cat internal/api/configuration.go)
+EOF
+
+  # Remove the OAuth code from the generated files.
+  # We don't use OAuth, and it pulls in a huge dependency on the Google Cloud libraries.
+  #
+  # See https://github.com/OpenAPITools/openapi-generator/issues/9281 for a feature request
+  # to add a toggle that would prevent OAuth code from even being generated.
+  sed -i.bak -e '/OAuth2 authentication/,+10d' -e 's#"golang.org/x/oauth2"##' internal/api/client.go
+  sed -i.bak -e '/OAuth2/,+2d' internal/api/configuration.go
+
+  # Replace all uses of int32 with int64 in our generated models.
+  #
+  # See https://github.com/OpenAPITools/openapi-generator/issues/9280 for a feature request
+  # to make the Go generator's number-handling compliant with the spec, so we can generate int64
+  # fields directly without making our public docs invalid.
+  for m in internal/api/model_*.go; do
+    sed -i.bak -e 's/int32/int64/g' ${m}
+  done
+
+  rm internal/api/*.bak
+)
+
+# Since we deleted the generated go.mod, run `go mod tidy` to update parent dependencies.
+(
+  cd "${ROOT_DIR}"
+  make fmt
+  go mod tidy
+)