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feat: adds azure metadata provider to cloudmeta pkg. (#4159)
feat: adds azure metadata provider to cloudmeta pkg. This adds azure metadata provider to cloudmeta pkg. Plus adds retries to azure metadata service using the github.com/hashicorp/go-retryablehttp package. Also adds some unit tests. Fixes: #4129
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,137 @@ | ||
| // Copyright (C) 2024 ScyllaDB | ||
|
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| package cloudmeta | ||
|
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| import ( | ||
| "context" | ||
| "encoding/json" | ||
| "net/http" | ||
| "time" | ||
|
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| "github.com/hashicorp/go-retryablehttp" | ||
| "github.com/pkg/errors" | ||
| "github.com/scylladb/go-log" | ||
| ) | ||
|
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| // azureBaseURL is a base url of azure metadata service. | ||
| const azureBaseURL = "http://169.254.169.254/metadata" | ||
|
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| // azureMetadata is a wrapper around azure metadata service. | ||
| type azureMetadata struct { | ||
| client *http.Client | ||
|
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| baseURL string | ||
| } | ||
|
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| // newAzureMetadata returns AzureMetadata service. | ||
| func newAzureMetadata(logger log.Logger) *azureMetadata { | ||
| return &azureMetadata{ | ||
| client: defaultClient(logger), | ||
| baseURL: azureBaseURL, | ||
| } | ||
| } | ||
|
|
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| func defaultClient(logger log.Logger) *http.Client { | ||
| client := retryablehttp.NewClient() | ||
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| client.RetryMax = 3 | ||
| client.RetryWaitMin = 500 * time.Millisecond | ||
| client.RetryWaitMax = 5 * time.Second | ||
| client.Logger = &logWrapper{ | ||
| logger: logger, | ||
| } | ||
|
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| transport := http.DefaultTransport.(*http.Transport).Clone() | ||
| // we must not use proxy for the metadata requests - see https://learn.microsoft.com/en-us/azure/virtual-machines/instance-metadata-service?tabs=linux#proxies. | ||
| transport.Proxy = nil | ||
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| client.HTTPClient = &http.Client{ | ||
| // Quite small timeout per request, because we have retries and also it's a local network call. | ||
| Timeout: 1 * time.Second, | ||
| Transport: transport, | ||
| } | ||
| return client.StandardClient() | ||
| } | ||
|
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| // Metadata return InstanceMetadata from azure if available. | ||
| func (azure *azureMetadata) Metadata(ctx context.Context) (InstanceMetadata, error) { | ||
| vmSize, err := azure.getVMSize(ctx) | ||
| if err != nil { | ||
| return InstanceMetadata{}, errors.Wrap(err, "azure.getVMSize") | ||
| } | ||
| if vmSize == "" { | ||
| return InstanceMetadata{}, errors.New("azure vmSize is empty") | ||
| } | ||
| return InstanceMetadata{ | ||
| CloudProvider: CloudProviderAzure, | ||
| InstanceType: vmSize, | ||
| }, nil | ||
| } | ||
|
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| // azureAPIVersion should be present in every request to metadata service in query parameter. | ||
| const azureAPIVersion = "2023-07-01" | ||
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| func (azure *azureMetadata) getVMSize(ctx context.Context) (string, error) { | ||
| req, err := http.NewRequestWithContext(ctx, http.MethodGet, azure.baseURL+"/instance", http.NoBody) | ||
| if err != nil { | ||
| return "", errors.Wrap(err, "http new request") | ||
| } | ||
|
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| // Setting required headers and query parameters - https://learn.microsoft.com/en-us/azure/virtual-machines/instance-metadata-service?tabs=linux#security-and-authentication. | ||
| req.Header.Add("Metadata", "true") | ||
| query := req.URL.Query() | ||
| query.Add("api-version", azureAPIVersion) | ||
| req.URL.RawQuery = query.Encode() | ||
|
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| resp, err := azure.client.Do(req) | ||
| if err != nil { | ||
| return "", errors.Wrap(err, "azure.client.Do") | ||
| } | ||
| defer resp.Body.Close() | ||
|
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| if resp.StatusCode != http.StatusOK { | ||
| return "", errors.Errorf("status code (%d) != 200", resp.StatusCode) | ||
| } | ||
|
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| var data azureMetadataResponse | ||
| if err := json.NewDecoder(resp.Body).Decode(&data); err != nil { | ||
| return "", errors.Wrap(err, "decode json") | ||
| } | ||
|
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| return data.Compute.VMSize, nil | ||
| } | ||
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| // azureMetadataResponse represents azure metadata service response. | ||
| // full response specification can be found here - https://learn.microsoft.com/en-us/azure/virtual-machines/instance-metadata-service?tabs=linux#response-1. | ||
| type azureMetadataResponse struct { | ||
| Compute azureCompute `json:"compute"` | ||
| } | ||
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| type azureCompute struct { | ||
| VMSize string `json:"vmSize"` | ||
| } | ||
|
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| // logWrapper implements go-retryablehttp.LeveledLogger interface. | ||
| type logWrapper struct { | ||
| logger log.Logger | ||
| } | ||
|
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| // Info wraps logger.Info method. | ||
| func (log *logWrapper) Info(msg string, keyVals ...interface{}) { | ||
| log.logger.Info(context.Background(), msg, keyVals...) | ||
| } | ||
|
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||
| // Error wraps logger.Error method. | ||
| func (log *logWrapper) Error(msg string, keyVals ...interface{}) { | ||
| log.logger.Error(context.Background(), msg, keyVals...) | ||
| } | ||
|
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| // Warn wraps logger.Error method. | ||
| func (log *logWrapper) Warn(msg string, keyVals ...interface{}) { | ||
| log.logger.Error(context.Background(), msg, keyVals...) | ||
| } | ||
|
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| // Debug wraps logger.Debug method. | ||
| func (log *logWrapper) Debug(msg string, keyVals ...interface{}) { | ||
| log.logger.Debug(context.Background(), msg, keyVals...) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,117 @@ | ||
| // Copyright (C) 2024 ScyllaDB | ||
|
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| package cloudmeta | ||
|
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| import ( | ||
| "context" | ||
| "net/http" | ||
| "net/http/httptest" | ||
| "testing" | ||
|
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| "github.com/scylladb/go-log" | ||
| ) | ||
|
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| func TestAzureMetadata(t *testing.T) { | ||
| testCases := []struct { | ||
| name string | ||
| handler http.Handler | ||
|
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| expectedCalls int | ||
| expectedErr bool | ||
| expectedMeta InstanceMetadata | ||
| }{ | ||
| { | ||
| name: "when response is 200", | ||
| handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { | ||
| testCheckRequireParams(t, r) | ||
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| w.Write([]byte(`{"compute":{"vmSize":"Standard-A3"}}`)) | ||
| }), | ||
| expectedCalls: 1, | ||
| expectedErr: false, | ||
| expectedMeta: InstanceMetadata{ | ||
| CloudProvider: CloudProviderAzure, | ||
| InstanceType: "Standard-A3", | ||
| }, | ||
| }, | ||
| { | ||
| name: "when response is 404: not retryable", | ||
| handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { | ||
| testCheckRequireParams(t, r) | ||
|
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| w.WriteHeader(http.StatusNotFound) | ||
| w.Write([]byte(`internal server error`)) | ||
| }), | ||
| expectedCalls: 1, | ||
| expectedErr: true, | ||
| expectedMeta: InstanceMetadata{}, | ||
| }, | ||
| { | ||
| name: "when response is 500: retryable", | ||
| handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { | ||
| testCheckRequireParams(t, r) | ||
|
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| w.WriteHeader(http.StatusInternalServerError) | ||
| w.Write([]byte(`internal server error`)) | ||
| }), | ||
| expectedCalls: 4, | ||
| expectedErr: true, | ||
| expectedMeta: InstanceMetadata{}, | ||
| }, | ||
| } | ||
|
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| for _, tc := range testCases { | ||
| t.Run(tc.name, func(t *testing.T) { | ||
| handler := &testHandler{Handler: tc.handler} | ||
| testSrv := httptest.NewServer(handler) | ||
| defer testSrv.Close() | ||
|
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| azureMeta := newAzureMetadata(log.NewDevelopment()) | ||
| azureMeta.baseURL = testSrv.URL | ||
|
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| meta, err := azureMeta.Metadata(context.Background()) | ||
| if tc.expectedErr && err == nil { | ||
| t.Fatalf("expected err: %v\n", err) | ||
| } | ||
| if !tc.expectedErr && err != nil { | ||
| t.Fatalf("unexpected err: %v\n", err) | ||
| } | ||
|
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| if tc.expectedCalls != handler.calls { | ||
| t.Fatalf("unexected number of calls: %d != %d", handler.calls, tc.expectedCalls) | ||
| } | ||
|
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| if meta.CloudProvider != tc.expectedMeta.CloudProvider { | ||
| t.Fatalf("unexpected cloud provider: %s", meta.CloudProvider) | ||
| } | ||
|
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| if meta.InstanceType != tc.expectedMeta.InstanceType { | ||
| t.Fatalf("unexpected instance type: %s", meta.InstanceType) | ||
| } | ||
| }) | ||
| } | ||
| } | ||
|
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| type testHandler struct { | ||
| http.Handler | ||
| // Keep track of how many times handler func has been called | ||
| // so we can test retries policy. | ||
| calls int | ||
| } | ||
|
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| func (th *testHandler) ServeHTTP(w http.ResponseWriter, t *http.Request) { | ||
| th.calls++ | ||
| th.Handler.ServeHTTP(w, t) | ||
| } | ||
|
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| func testCheckRequireParams(t *testing.T, r *http.Request) { | ||
| t.Helper() | ||
| metadataHeader := r.Header.Get("Metadata") | ||
| if metadataHeader != "true" { | ||
| t.Fatalf("Metadata: true header is required") | ||
| } | ||
| apiVersion := r.URL.Query().Get("api-version") | ||
| if apiVersion != azureAPIVersion { | ||
| t.Fatalf("unexpected ?api-version: %s", apiVersion) | ||
| } | ||
| } |
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