pkg/pricing/client/pricingapi.go

/*
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package client

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
)

const (
	apiVersion = "2021-10-01-preview"
	pricingURL = "https://prices.azure.com/api/retail/prices?api-version=" + apiVersion
)

type PricingAPI interface {
	GetProductsPricePages(context.Context, []*Filter, func(output *ProductsPricePage)) error
}

type pricingAPI struct{}

func New() PricingAPI {
	return &pricingAPI{}
}

func (papi *pricingAPI) GetProductsPricePages(ctx context.Context, filters []*Filter, pageHandler func(output *ProductsPricePage)) error {
	nextURL := pricingURL

	if len(filters) > 0 {
		filterParams := []string{}
		for _, filter := range filters {
			filterParams = append(filterParams, filter.String())
		}

		filterParamsEscaped := url.QueryEscape(strings.Join(filterParams[:], " and "))

		nextURL += fmt.Sprintf("&$filter=%s", filterParamsEscaped)
	}

	for nextURL != "" {
		res, err := http.Get(nextURL)
		if err != nil {
			return err
		}

		if res.StatusCode != 200 {
			return fmt.Errorf("got a non-200 status code: %d", res.StatusCode)
		}

		resBody, err := io.ReadAll(res.Body)
		if err != nil {
			return err
		}

		page := ProductsPricePage{}
		err = json.Unmarshal(resBody, &page)
		if err != nil {
			return err
		}

		pageHandler(&page)
		nextURL = page.NextPageLink
	}
	return nil
}