terraform/internal/getproviders/http_mirror_source.go

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package getproviders
import (
"encoding/json"
"fmt"
"io"
"log"
"mime"
"net/http"
"net/url"
"path"
"strings"
"github.com/hashicorp/go-retryablehttp"
svchost "github.com/hashicorp/terraform-svchost"
svcauth "github.com/hashicorp/terraform-svchost/auth"
"golang.org/x/net/idna"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/helper/logging"
"github.com/hashicorp/terraform/httpclient"
"github.com/hashicorp/terraform/version"
)
// HTTPMirrorSource is a source that reads provider metadata from a provider
// mirror that is accessible over the HTTP provider mirror protocol.
type HTTPMirrorSource struct {
baseURL *url.URL
creds svcauth.CredentialsSource
httpClient *retryablehttp.Client
}
var _ Source = (*HTTPMirrorSource)(nil)
// NewHTTPMirrorSource constructs and returns a new network mirror source with
// the given base URL. The relative URL offsets defined by the HTTP mirror
// protocol will be resolve relative to the given URL.
//
// The given URL must use the "https" scheme, or this function will panic.
// (When the URL comes from user input, such as in the CLI config, it's the
// UI/config layer's responsibility to validate this and return a suitable
// error message for the end-user audience.)
func NewHTTPMirrorSource(baseURL *url.URL, creds svcauth.CredentialsSource) *HTTPMirrorSource {
httpClient := httpclient.New()
httpClient.Timeout = requestTimeout
httpClient.CheckRedirect = func(req *http.Request, via []*http.Request) error {
// If we get redirected more than five times we'll assume we're
// in a redirect loop and bail out, rather than hanging forever.
if len(via) > 5 {
return fmt.Errorf("too many redirects")
}
return nil
}
return newHTTPMirrorSourceWithHTTPClient(baseURL, creds, httpClient)
}
func newHTTPMirrorSourceWithHTTPClient(baseURL *url.URL, creds svcauth.CredentialsSource, httpClient *http.Client) *HTTPMirrorSource {
if baseURL.Scheme != "https" {
panic("non-https URL for HTTP mirror")
}
// We borrow the retry settings and behaviors from the registry client,
// because our needs here are very similar to those of the registry client.
retryableClient := retryablehttp.NewClient()
retryableClient.HTTPClient = httpClient
retryableClient.RetryMax = discoveryRetry
retryableClient.RequestLogHook = requestLogHook
retryableClient.ErrorHandler = maxRetryErrorHandler
logOutput, err := logging.LogOutput()
if err != nil {
log.Printf("[WARN] Failed to set up provider HTTP mirror logger, so continuing without client logging: %s", err)
}
retryableClient.Logger = log.New(logOutput, "", log.Flags())
return &HTTPMirrorSource{
baseURL: baseURL,
creds: creds,
httpClient: retryableClient,
}
}
// AvailableVersions retrieves the available versions for the given provider
// from the object's underlying HTTP mirror service.
func (s *HTTPMirrorSource) AvailableVersions(provider addrs.Provider) (VersionList, Warnings, error) {
log.Printf("[DEBUG] Querying available versions of provider %s at network mirror %s", provider.String(), s.baseURL.String())
endpointPath := path.Join(
provider.Hostname.String(),
provider.Namespace,
provider.Type,
"index.json",
)
statusCode, body, finalURL, err := s.get(endpointPath)
defer func() {
if body != nil {
body.Close()
}
}()
if err != nil {
return nil, nil, s.errQueryFailed(provider, err)
}
switch statusCode {
case http.StatusOK:
// Great!
case http.StatusNotFound:
return nil, nil, ErrProviderNotFound{
Provider: provider,
}
case http.StatusUnauthorized, http.StatusForbidden:
return nil, nil, s.errUnauthorized(finalURL)
default:
return nil, nil, s.errQueryFailed(provider, fmt.Errorf("server returned unsuccessful status %d", statusCode))
}
// If we got here then the response had status OK and so our body
// will be non-nil and should contain some JSON for us to parse.
type ResponseBody struct {
Versions map[string]struct{} `json:"versions"`
}
var bodyContent ResponseBody
dec := json.NewDecoder(body)
if err := dec.Decode(&bodyContent); err != nil {
return nil, nil, s.errQueryFailed(provider, fmt.Errorf("invalid response content from mirror server: %s", err))
}
if len(bodyContent.Versions) == 0 {
return nil, nil, nil
}
ret := make(VersionList, 0, len(bodyContent.Versions))
for versionStr := range bodyContent.Versions {
version, err := ParseVersion(versionStr)
if err != nil {
log.Printf("[WARN] Ignoring invalid %s version string %q in provider mirror response", provider, versionStr)
continue
}
ret = append(ret, version)
}
ret.Sort()
return ret, nil, nil
}
// PackageMeta retrieves metadata for the requested provider package
// from the object's underlying HTTP mirror service.
func (s *HTTPMirrorSource) PackageMeta(provider addrs.Provider, version Version, target Platform) (PackageMeta, error) {
log.Printf("[DEBUG] Finding package URL for %s v%s on %s via network mirror %s", provider.String(), version.String(), target.String(), s.baseURL.String())
endpointPath := path.Join(
provider.Hostname.String(),
provider.Namespace,
provider.Type,
version.String()+".json",
)
statusCode, body, finalURL, err := s.get(endpointPath)
defer func() {
if body != nil {
body.Close()
}
}()
if err != nil {
return PackageMeta{}, s.errQueryFailed(provider, err)
}
switch statusCode {
case http.StatusOK:
// Great!
case http.StatusNotFound:
// A 404 Not Found for a version we previously saw in index.json is
// a protocol error, so we'll report this as "query failed.
return PackageMeta{}, s.errQueryFailed(provider, fmt.Errorf("provider mirror does not have archive index for previously-reported %s version %s", provider, version))
case http.StatusUnauthorized, http.StatusForbidden:
return PackageMeta{}, s.errUnauthorized(finalURL)
default:
return PackageMeta{}, s.errQueryFailed(provider, fmt.Errorf("server returned unsuccessful status %d", statusCode))
}
// If we got here then the response had status OK and so our body
// will be non-nil and should contain some JSON for us to parse.
type ResponseArchiveMeta struct {
RelativeURL string `json:"url"`
Hashes []string
}
type ResponseBody struct {
Archives map[string]*ResponseArchiveMeta `json:"archives"`
}
var bodyContent ResponseBody
dec := json.NewDecoder(body)
if err := dec.Decode(&bodyContent); err != nil {
return PackageMeta{}, s.errQueryFailed(provider, fmt.Errorf("invalid response content from mirror server: %s", err))
}
archiveMeta, ok := bodyContent.Archives[target.String()]
if !ok {
return PackageMeta{}, ErrPlatformNotSupported{
Provider: provider,
Version: version,
Platform: target,
MirrorURL: s.baseURL,
}
}
relURL, err := url.Parse(archiveMeta.RelativeURL)
if err != nil {
return PackageMeta{}, s.errQueryFailed(
provider,
fmt.Errorf("provider mirror returned invalid URL %q: %s", archiveMeta.RelativeURL, err),
)
}
absURL := finalURL.ResolveReference(relURL)
ret := PackageMeta{
Provider: provider,
Version: version,
TargetPlatform: target,
Location: PackageHTTPURL(absURL.String()),
Filename: path.Base(absURL.Path),
}
// A network mirror might not provide any hashes at all, in which case
// the package has no source-defined authentication whatsoever.
if len(archiveMeta.Hashes) > 0 {
ret.Authentication = NewPackageHashAuthentication(archiveMeta.Hashes)
}
return ret, nil
}
// ForDisplay returns a string description of the source for user-facing output.
func (s *HTTPMirrorSource) ForDisplay(provider addrs.Provider) string {
return "provider mirror at " + s.baseURL.String()
}
// mirrorHost extracts the hostname portion of the configured base URL and
// returns it as a svchost.Hostname, normalized in the usual ways.
//
// If the returned error is non-nil then the given hostname doesn't comply
// with the IETF RFC 5891 section 5.3 and 5.4 validation rules, and thus cannot
// be interpreted as a valid Terraform service host. The IDNA validation errors
// are unfortunately usually not very user-friendly, but they are also
// relatively rare because the IDNA normalization rules are quite tolerant.
func (s *HTTPMirrorSource) mirrorHost() (svchost.Hostname, error) {
return svchostFromURL(s.baseURL)
}
// mirrorHostCredentials returns the HostCredentials, if any, for the hostname
// included in the mirror base URL.
//
// It might return an error if the mirror base URL is invalid, or if the
// credentials lookup itself fails.
func (s *HTTPMirrorSource) mirrorHostCredentials() (svcauth.HostCredentials, error) {
hostname, err := s.mirrorHost()
if err != nil {
return nil, fmt.Errorf("invalid provider mirror base URL %s: %s", s.baseURL.String(), err)
}
if s.creds == nil {
// No host-specific credentials, then.
return nil, nil
}
return s.creds.ForHost(hostname)
}
// get is the shared functionality for querying a JSON index from a mirror.
//
// It only handles the raw HTTP request. The "body" return value is the
// reader from the response if and only if the response status code is 200 OK
// and the Content-Type is application/json. In all other cases it's nil.
// If body is non-nil then the caller must close it after reading it.
//
// If the "finalURL" return value is not empty then it's the URL that actually
// produced the returned response, possibly after following some redirects.
func (s *HTTPMirrorSource) get(relativePath string) (statusCode int, body io.ReadCloser, finalURL *url.URL, error error) {
endpointPath, err := url.Parse(relativePath)
if err != nil {
// Should never happen because the caller should validate all of the
// components it's including in the path.
return 0, nil, nil, err
}
endpointURL := s.baseURL.ResolveReference(endpointPath)
req, err := retryablehttp.NewRequest("GET", endpointURL.String(), nil)
if err != nil {
return 0, nil, endpointURL, err
}
req.Request.Header.Set(terraformVersionHeader, version.String())
creds, err := s.mirrorHostCredentials()
if err != nil {
return 0, nil, endpointURL, fmt.Errorf("failed to determine request credentials: %s", err)
}
if creds != nil {
// Note that if the initial requests gets redirected elsewhere
// then the credentials will still be included in the new request,
// even if they are on a different hostname. This is intentional
// and consistent with how we handle credentials for other
// Terraform-native services, because the user model is to configure
// credentials for the "friendly hostname" they configured, not for
// whatever hostname ends up ultimately serving the request as an
// implementation detail.
creds.PrepareRequest(req.Request)
}
resp, err := s.httpClient.Do(req)
if err != nil {
return 0, nil, endpointURL, err
}
defer func() {
// If we're not returning the body then we'll close it
// before we return.
if body == nil {
resp.Body.Close()
}
}()
// After this point, our final URL return value should always be the
// one from resp.Request, because that takes into account any redirects
// we followed along the way.
finalURL = resp.Request.URL
if resp.StatusCode == http.StatusOK {
// If and only if we get an OK response, we'll check that the response
// type is JSON and return the body reader.
ct := resp.Header.Get("Content-Type")
mt, params, err := mime.ParseMediaType(ct)
if err != nil {
return 0, nil, finalURL, fmt.Errorf("response has invalid Content-Type: %s", err)
}
if mt != "application/json" {
return 0, nil, finalURL, fmt.Errorf("response has invalid Content-Type: must be application/json")
}
for name := range params {
// The application/json content-type has no defined parameters,
// but some servers are configured to include a redundant "charset"
// parameter anyway, presumably out of a sense of completeness.
// We'll ignore them but warn that we're ignoring them in case the
// subsequent parsing fails due to the server trying to use an
// unsupported character encoding. (RFC 7159 defines its own
// JSON-specific character encoding rules.)
log.Printf("[WARN] Network mirror returned %q as part of its JSON content type, which is not defined. Ignoring.", name)
}
body = resp.Body
}
return resp.StatusCode, body, finalURL, nil
}
func (s *HTTPMirrorSource) errQueryFailed(provider addrs.Provider, err error) error {
return ErrQueryFailed{
Provider: provider,
Wrapped: err,
MirrorURL: s.baseURL,
}
}
func (s *HTTPMirrorSource) errUnauthorized(finalURL *url.URL) error {
hostname, err := svchostFromURL(finalURL)
if err != nil {
// Again, weird but we'll tolerate it.
return fmt.Errorf("invalid credentials for %s", finalURL)
}
return ErrUnauthorized{
Hostname: hostname,
// We can't easily tell from here whether we had credentials or
// not, so for now we'll just assume we did because "host rejected
// the given credentials" is, hopefully, still understandable in
// the event that there were none. (If this ends up being confusing
// in practice then we'll need to do some refactoring of how
// we handle credentials in this source.)
HaveCredentials: true,
}
}
func svchostFromURL(u *url.URL) (svchost.Hostname, error) {
raw := u.Host
// When "friendly hostnames" appear in Terraform-specific identifiers we
// typically constrain their syntax more strictly than the
// Internationalized Domain Name specifications call for, such as
// forbidding direct use of punycode, but in this case we're just
// working with a standard http: or https: URL and so we'll first use the
// IDNA "lookup" rules directly, with no additional notational constraints,
// to effectively normalize away the differences that would normally
// produce an error.
var portPortion string
if colonPos := strings.Index(raw, ":"); colonPos != -1 {
raw, portPortion = raw[:colonPos], raw[colonPos:]
}
// HTTPMirrorSource requires all URLs to be https URLs, because running
// a network mirror over HTTP would potentially transmit any configured
// credentials in cleartext. Therefore we don't need to do any special
// handling of default ports here, because svchost.Hostname already
// considers the absense of a port to represent the standard HTTPS port
// 443, and will normalize away an explicit specification of port 443
// in svchost.ForComparison below.
normalized, err := idna.Display.ToUnicode(raw)
if err != nil {
return svchost.Hostname(""), err
}
// If ToUnicode succeeded above then "normalized" is now a hostname in the
// normalized IDNA form, with any direct punycode already interpreted and
// the case folding and other normalization rules applied. It should
// therefore now be accepted by svchost.ForComparison with no additional
// errors, but the port portion can still potentially be invalid.
return svchost.ForComparison(normalized + portPortion)
}