Initial Commit

pkg/fetcher/fetcher.go

@@ -0,0 +1,99 @@
+package fetcher
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+
+	"git.cryptic.systems/volker.raschek/dcmerge/pkg/domain/dockerCompose"
+	"gopkg.in/yaml.v3"
+)
+
+func Fetch(urls ...string) ([]*dockerCompose.Config, error) {
+	dockerComposeConfigs := make([]*dockerCompose.Config, 0)
+
+	for _, rawURL := range urls {
+		dockerComposeURL, err := url.Parse(rawURL)
+		if err != nil {
+			return nil, err
+		}
+
+		switch {
+		case dockerComposeURL.Scheme == "http" || dockerComposeURL.Scheme == "https":
+			dockerComposeConfig, err := getDockerComposeViaHTTP(dockerComposeURL.String())
+			if err != nil {
+				return nil, err
+			}
+
+			dockerComposeConfigs = append(dockerComposeConfigs, dockerComposeConfig)
+		case dockerComposeURL.Scheme == "file":
+			fallthrough
+		default:
+			dockerComposeConfig, err := readDockerComposeFromFile(dockerComposeURL.Path)
+			if err != nil {
+				return nil, err
+			}
+
+			dockerComposeConfigs = append(dockerComposeConfigs, dockerComposeConfig)
+		}
+	}
+
+	return dockerComposeConfigs, nil
+}
+
+var ErrorPathIsDir error = errors.New("Path is a directory")
+
+func getDockerComposeViaHTTP(url string) (*dockerCompose.Config, error) {
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("Received unexpected HTTP-Statuscode %v", resp.StatusCode)
+	}
+
+	dockerCompose := dockerCompose.NewConfig()
+
+	yamlDecoder := yaml.NewDecoder(resp.Body)
+	err = yamlDecoder.Decode(&dockerCompose)
+	if err != nil {
+		return nil, err
+	}
+
+	return dockerCompose, nil
+}
+
+func readDockerComposeFromFile(name string) (*dockerCompose.Config, error) {
+	fileStat, err := os.Stat(name)
+	switch {
+	case errors.Is(err, os.ErrNotExist):
+		return nil, err
+	case fileStat.IsDir():
+		return nil, fmt.Errorf("%w: %s", ErrorPathIsDir, name)
+	}
+
+	file, err := os.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	dockerCompose := dockerCompose.NewConfig()
+
+	yamlDecoder := yaml.NewDecoder(file)
+	err = yamlDecoder.Decode(&dockerCompose)
+	if err != nil {
+		return nil, err
+	}
+
+	return dockerCompose, nil
+}