From aa9f394cdcb09c0690ec8cadf0a3cb8e4f062f0b Mon Sep 17 00:00:00 2001
From: gw0 <gw.2022@ena.one>
Date: Tue, 1 Mar 2022 12:01:08 +0100
Subject: [PATCH] Add support for providing additional HTTP headers

---
 docs/index.md       |  1 +
 grafana/provider.go | 49 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/docs/index.md b/docs/index.md
index f9093adc6..ef4c3c1ca 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -28,6 +28,7 @@ provider "grafana" {
 - **ca_cert** (String) Certificate CA bundle to use to verify the Grafana server's certificate. May alternatively be set via the `GRAFANA_CA_CERT` environment variable.
 - **cloud_api_key** (String, Sensitive) API key for Grafana Cloud. May alternatively be set via the `GRAFANA_CLOUD_API_KEY` environment variable.
 - **cloud_api_url** (String) Grafana Cloud's API URL. May alternatively be set via the `GRAFANA_CLOUD_API_URL` environment variable.
+- **http_headers** (Map of String, Sensitive) Optional. HTTP headers mapping keys to values used for accessing the Grafana API. May alternatively be set via the `GRAFANA_HTTP_HEADERS` environment variable in JSON format.
 - **insecure_skip_verify** (Boolean) Skip TLS certificate verification. May alternatively be set via the `GRAFANA_INSECURE_SKIP_VERIFY` environment variable.
 - **org_id** (Number) The organization id to operate on within grafana. May alternatively be set via the `GRAFANA_ORG_ID` environment variable.
 - **retries** (Number) The amount of retries to use for Grafana API calls. May alternatively be set via the `GRAFANA_RETRIES` environment variable.
diff --git a/grafana/provider.go b/grafana/provider.go
index 07fe579ab..3d7db73d4 100644
--- a/grafana/provider.go
+++ b/grafana/provider.go
@@ -4,9 +4,11 @@ import (
 	"context"
 	"crypto/tls"
 	"crypto/x509"
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"net/url"
+	"os"
 	"regexp"
 	"strings"
 
@@ -60,6 +62,13 @@ func Provider(version string) func() *schema.Provider {
 					Description:  "API token or basic auth username:password. May alternatively be set via the `GRAFANA_AUTH` environment variable.",
 					AtLeastOneOf: []string{"auth", "cloud_api_key", "sm_access_token"},
 				},
+				"http_headers": {
+					Type:        schema.TypeMap,
+					Optional:    true,
+					Sensitive:   true,
+					DefaultFunc: JSONEnvDefaultFunc("GRAFANA_HTTP_HEADERS", nil),
+					Description: "Optional. HTTP headers mapping keys to values used for accessing the Grafana API. May alternatively be set via the `GRAFANA_HTTP_HEADERS` environment variable in JSON format.",
+				},
 				"retries": {
 					Type:        schema.TypeInt,
 					Optional:    true,
@@ -267,6 +276,29 @@ func createGrafanaClient(d *schema.ResourceData) (string, *gapi.Config, *gapi.Cl
 	} else {
 		cfg.APIKey = auth[0]
 	}
+
+	headersMap := d.Get("http_headers").(map[string]interface{})
+	if headersMap != nil && len(headersMap) == 0 {
+		// Workaround for a bug when DefaultFunc returns a schema.TypeMap
+		headersMapAbs, err := JSONEnvDefaultFunc("GRAFANA_HTTP_HEADERS", nil)()
+		if err != nil {
+			return "", nil, nil, err
+		}
+		if headersMapAbs != nil {
+			headersMap = headersMapAbs.(map[string]interface{})
+		}
+	}
+	if headersMap != nil {
+		// Convert headers from map[string]interface{} to map[string]string
+		headers := make(map[string]string)
+		for k, v := range headersMap {
+			if v, ok := v.(string); ok {
+				headers[k] = v
+			}
+		}
+		cfg.HTTPHeaders = headers
+	}
+
 	gclient, err := gapi.New(apiURL, cfg)
 	if err != nil {
 		return "", nil, nil, err
@@ -305,3 +337,20 @@ func createSMClient(d *schema.ResourceData) *smapi.Client {
 	smURL := d.Get("sm_url").(string)
 	return smapi.NewClient(smURL, smToken, nil)
 }
+
+// JSONEnvDefaultFunc is a helper function that parses the given environment
+// variable as a JSON object, or returns the default value otherwise.
+func JSONEnvDefaultFunc(k string, dv interface{}) schema.SchemaDefaultFunc {
+	return func() (interface{}, error) {
+		if valStr := os.Getenv(k); valStr != "" {
+			var valObj map[string]interface{}
+			err := json.Unmarshal([]byte(valStr), &valObj)
+			if err != nil {
+				return nil, err
+			}
+			return valObj, nil
+		}
+
+		return dv, nil
+	}
+}