Add F5 Cloud Exporter (1/3) (#1965)

* added initial F5 Cloud Exporter

* updated f5_cloud_auth config reference to 'auth'

Signed-off-by: Granville Schmidt <1246157+gramidt@users.noreply.github.com>

* updated README with suggestions

Signed-off-by: Granville Schmidt <1246157+gramidt@users.noreply.github.com>

exporter/f5cloudexporter/Makefile

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+include ../../Makefile.Common

exporter/f5cloudexporter/README.md

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+# F5 Cloud Exporter
+
+Exports data via HTTP to [F5 Cloud](https://portal.cloudservices.f5.com/).
+
+Supported pipeline types: metrics, traces, logs
+
+> :construction: This exporter is in beta and configuration fields are subject to change.
+
+## Getting Started
+
+The following settings are required:
+
+- `endpoint` (no default): The URL to send data to. See your F5 Cloud account for details.
+- `source` (no default): A unique identifier that is used to distinguish where this data is coming from (e.g. dev_cluster). This is in 
+  addition to the pipeline attributes and resources.
+- `auth.credential_file` (no default): Path to the credential file used to authenticate this client. See your F5 
+  Cloud account for details.
+
+The following settings can be optionally configured:
+
+- `auth.audience` (no default): Identifies the recipient that the authentication JWT is intended for. See your F5 Cloud 
+  account for details.
+
+- `timeout` (default = 30s): HTTP request time limit. For details see https://golang.org/pkg/net/http/#Client
+- `read_buffer_size` (default = 0): ReadBufferSize for HTTP client.
+- `write_buffer_size` (default = 512 * 1024): WriteBufferSize for HTTP client.
+
+Example:
+
+```yaml
+f5cloud:
+  endpoint: https://<ENDPOINT_FOUND_IN_F5_CLOUD_PORTAL>
+  source: prod
+  auth:
+    credential_file: "/etc/creds/key.json"
+```
+
+The full list of settings exposed for this exporter are documented [here](./config.go) with detailed sample
+configurations [here](./testdata/config.yaml).
+
+This exporter also offers proxy support as documented 
+[here](https://github.com/open-telemetry/opentelemetry-collector/tree/master/exporter#proxy-support).

exporter/f5cloudexporter/auth.go

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+// Copyright The OpenTelemetry Authors
+//
+// 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 f5cloudexporter
+
+import (
+	"fmt"
+	"net/http"
+
+	"golang.org/x/oauth2"
+)
+
+const (
+	SourceHeader = "X-F5-Source"
+)
+
+type f5CloudAuthRoundTripper struct {
+	transport   http.RoundTripper
+	tokenSource oauth2.TokenSource
+	source      string
+}
+
+func (rt *f5CloudAuthRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	// Clone request to ensure thread safety
+	req2 := req.Clone(req.Context())
+
+	// Add authorization header
+	tkn, err := rt.tokenSource.Token()
+	if err != nil {
+		return nil, err
+	}
+	tkn.SetAuthHeader(req2)
+
+	// Add F5 specific headers
+	req2.Header.Add(SourceHeader, rt.source)
+
+	resp, err := rt.transport.RoundTrip(req2)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp, nil
+}
+
+func newF5CloudAuthRoundTripper(ts oauth2.TokenSource, source string, next http.RoundTripper) (http.RoundTripper, error) {
+	if ts == nil {
+		return nil, fmt.Errorf("no TokenSource exists")
+	}
+
+	if len(source) == 0 {
+		return nil, fmt.Errorf("no source provided")
+	}
+
+	rt := f5CloudAuthRoundTripper{
+		transport:   next,
+		tokenSource: ts,
+		source:      source,
+	}
+
+	return &rt, nil
+}

exporter/f5cloudexporter/auth_test.go

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+// Copyright The OpenTelemetry Authors
+//
+// 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 f5cloudexporter
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/oauth2"
+)
+
+type ErrorRoundTripper struct{}
+
+func (ert *ErrorRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
+	return nil, fmt.Errorf("error")
+}
+
+func TestF5CloudAuthRoundTripper_RoundTrip(t *testing.T) {
+	validTokenSource := createMockTokenSource()
+	source := "tests"
+
+	defaultRoundTripper := (http.RoundTripper)(http.DefaultTransport.(*http.Transport).Clone())
+	errorRoundTripper := &ErrorRoundTripper{}
+
+	tests := []struct {
+		name        string
+		rt          http.RoundTripper
+		token       oauth2.TokenSource
+		shouldError bool
+	}{
+		{
+			name:        "Test valid token source",
+			rt:          defaultRoundTripper,
+			token:       validTokenSource,
+			shouldError: false,
+		},
+		{
+			name:        "Test invalid token source",
+			rt:          defaultRoundTripper,
+			token:       &InvalidTokenSource{},
+			shouldError: true,
+		},
+		{
+			name:        "Test error in next round tripper",
+			rt:          errorRoundTripper,
+			token:       validTokenSource,
+			shouldError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				assert.Equal(t, "Bearer test_access_token", r.Header.Get("Authorization"))
+				assert.Equal(t, "tests", r.Header.Get(SourceHeader))
+			}))
+			defer server.Close()
+			rt, err := newF5CloudAuthRoundTripper(tt.token, source, tt.rt)
+			assert.NoError(t, err)
+			req, err := http.NewRequest("POST", server.URL, strings.NewReader(""))
+			assert.NoError(t, err)
+			res, err := rt.RoundTrip(req)
+			if tt.shouldError {
+				assert.Nil(t, res)
+				assert.Error(t, err)
+				return
+			}
+			assert.NoError(t, err)
+			assert.Equal(t, res.StatusCode, 200)
+		})
+	}
+}
+
+func TestCreateF5CloudAuthRoundTripperWithToken(t *testing.T) {
+	defaultRoundTripper := (http.RoundTripper)(http.DefaultTransport.(*http.Transport).Clone())
+
+	token := createMockTokenSource()
+	source := "test"
+
+	tests := []struct {
+		name        string
+		token       oauth2.TokenSource
+		source      string
+		rt          http.RoundTripper
+		shouldError bool
+	}{
+		{
+			name:        "success_case",
+			token:       token,
+			source:      source,
+			rt:          defaultRoundTripper,
+			shouldError: false,
+		},
+		{
+			name:        "no_token_provided_error",
+			token:       nil,
+			source:      source,
+			rt:          defaultRoundTripper,
+			shouldError: true,
+		},
+		{
+			name:        "no_source_provided_error",
+			token:       token,
+			source:      "",
+			rt:          defaultRoundTripper,
+			shouldError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := newF5CloudAuthRoundTripper(tt.token, tt.source, tt.rt)
+			if tt.shouldError {
+				assert.Error(t, err)
+				return
+			}
+			assert.NoError(t, err)
+		})
+	}
+}
+
+func createMockTokenSource() oauth2.TokenSource {
+	tkn := &oauth2.Token{
+		AccessToken:  "test_access_token",
+		TokenType:    "",
+		RefreshToken: "",
+		Expiry:       time.Time{},
+	}
+
+	return oauth2.StaticTokenSource(tkn)
+}
+
+type InvalidTokenSource struct{}
+
+func (ts *InvalidTokenSource) Token() (*oauth2.Token, error) {
+	return nil, fmt.Errorf("bad TokenSource for testing")
+}

exporter/f5cloudexporter/config.go

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+// Copyright The OpenTelemetry Authors
+//
+// 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 f5cloudexporter
+
+import (
+	"fmt"
+	"net/url"
+	"os"
+
+	otlphttp "go.opentelemetry.io/collector/exporter/otlphttpexporter"
+)
+
+// Config defines configuration for F5 Cloud exporter.
+type Config struct {
+	// Config represents the OTLP HTTP Exporter configuration.
+	otlphttp.Config `mapstructure:",squash"`
+
+	// Source represents a unique identifier that is used to distinguish where this data is coming from.
+	Source string `mapstructure:"source"`
+
+	// AuthConfig represents the F5 Cloud authentication configuration options.
+	AuthConfig AuthConfig `mapstructure:"auth"`
+}
+
+func (c *Config) sanitize() error {
+	if len(c.Endpoint) == 0 {
+		return fmt.Errorf("missing required \"endpoint\" setting")
+	}
+
+	endpointURL, err := url.Parse(c.Endpoint)
+	if err != nil {
+		return err
+	}
+
+	if len(c.Source) == 0 {
+		return fmt.Errorf("missing required \"source\" setting")
+	}
+
+	if len(c.AuthConfig.CredentialFile) == 0 {
+		return fmt.Errorf("missing required \"auth.credential_file\" setting")
+	}
+
+	if _, err := os.Stat(c.AuthConfig.CredentialFile); os.IsNotExist(err) {
+		return fmt.Errorf("the provided \"auth.credential_file\" does not exist")
+	}
+
+	if len(c.AuthConfig.Audience) == 0 {
+		c.AuthConfig.Audience = fmt.Sprintf("%s://%s", endpointURL.Scheme, endpointURL.Hostname())
+	}
+
+	return nil
+}
+
+// AuthConfig defines F5 Cloud authentication configurations for F5CloudAuthRoundTripper
+type AuthConfig struct {
+	// CredentialFile is the F5 Cloud credentials for your designated account.
+	CredentialFile string `mapstructure:"credential_file"`
+
+	// Audience is the F5 Cloud audience for your designated account.
+	Audience string `mapstructure:"audience"`
+}