Support Loki datasource attributes (#397)

`maxLines` + `derivedFields`

Needs grafana/grafana-api-golang-client#65

Closes #375 and #144

Author: julienduchesne

docs/resources/data_source.md

@@ -114,6 +114,7 @@ Optional:
 - **default_bucket** (String) (InfluxDB) The default bucket for the data source.
 - **default_project** (String) (Stackdriver) The default project for the data source.
 - **default_region** (String) (CloudWatch, Athena) The default region for the data source.
+- **derived_field** (Block List) (Loki) See https://grafana.com/docs/grafana/latest/datasources/loki/#derived-fields (see [below for nested schema](#nestedblock--json_data--derived_field))
 - **encrypt** (String) (MSSQL) Connection SSL encryption handling: 'disable', 'false' or 'true'.
 - **es_version** (String) (Elasticsearch) Elasticsearch semantic version (Grafana v8.0+).
 - **external_id** (String) (CloudWatch, Athena) If you are assuming a role in another account, that has been created with an external ID, specify the external ID here.
@@ -125,6 +126,7 @@ Optional:
 - **log_message_field** (String) (Elasticsearch) Which field should be used as the log message.
 - **max_concurrent_shard_requests** (Number) (Elasticsearch) Maximum number of concurrent shard requests.
 - **max_idle_conns** (Number) (MySQL, PostgreSQL and MSSQL) Maximum number of connections in the idle connection pool (Grafana v5.4+).
+- **max_lines** (Number) (Loki) Upper limit for the number of log lines returned by Loki
 - **max_open_conns** (Number) (MySQL, PostgreSQL and MSSQL) Maximum number of open connections to the database (Grafana v5.4+).
 - **org_slug** (String) (Sentry) Organization slug.
 - **organization** (String) (InfluxDB) An organization is a workspace for a group of users. All dashboards, tasks, buckets, members, etc., belong to an organization.
@@ -151,6 +153,17 @@ Optional:
 - **version** (String) (InfluxDB) InfluxQL or Flux.
 - **workgroup** (String) (Athena) Workgroup to use.
 
+<a id="nestedblock--json_data--derived_field"></a>
+### Nested Schema for `json_data.derived_field`
+
+Optional:
+
+- **datasource_uid** (String)
+- **matcher_regex** (String)
+- **name** (String)
+- **url** (String)
+
+
 
 <a id="nestedblock--secure_json_data"></a>
 ### Nested Schema for `secure_json_data`

grafana/resource_data_source.go

@@ -145,6 +145,31 @@ source selected (via the 'type' argument).
 							Optional:    true,
 							Description: "(CloudWatch, Athena) The default region for the data source.",
 						},
+						"derived_field": {
+							Type: schema.TypeList,
+							Elem: &schema.Resource{
+								Schema: map[string]*schema.Schema{
+									"name": {
+										Type:     schema.TypeString,
+										Optional: true,
+									},
+									"matcher_regex": {
+										Type:     schema.TypeString,
+										Optional: true,
+									},
+									"url": {
+										Type:     schema.TypeString,
+										Optional: true,
+									},
+									"datasource_uid": {
+										Type:     schema.TypeString,
+										Optional: true,
+									},
+								},
+							},
+							Optional:    true,
+							Description: "(Loki) See https://grafana.com/docs/grafana/latest/datasources/loki/#derived-fields",
+						},
 						"encrypt": {
 							Type:        schema.TypeString,
 							Optional:    true,
@@ -212,6 +237,11 @@ source selected (via the 'type' argument).
 							Optional:    true,
 							Description: "(MySQL, PostgreSQL and MSSQL) Maximum number of connections in the idle connection pool (Grafana v5.4+).",
 						},
+						"max_lines": {
+							Type:        schema.TypeInt,
+							Optional:    true,
+							Description: "(Loki) Upper limit for the number of log lines returned by Loki ",
+						},
 						"max_open_conns": {
 							Type:        schema.TypeInt,
 							Optional:    true,
@@ -579,6 +609,17 @@ func makeDataSource(d *schema.ResourceData) (*gapi.DataSource, error) {
 }
 
 func makeJSONData(d *schema.ResourceData) gapi.JSONData {
+	var derivedFields []gapi.LokiDerivedField
+	for _, field := range d.Get("json_data.0.derived_field").([]interface{}) {
+		derivedField := field.(map[string]interface{})
+		derivedFields = append(derivedFields, gapi.LokiDerivedField{
+			Name:          derivedField["name"].(string),
+			MatcherRegex:  derivedField["matcher_regex"].(string),
+			URL:           derivedField["url"].(string),
+			DatasourceUID: derivedField["datasource_uid"].(string),
+		})
+	}
+
 	return gapi.JSONData{
 		AssumeRoleArn:              d.Get("json_data.0.assume_role_arn").(string),
 		AuthType:                   d.Get("json_data.0.auth_type").(string),
@@ -591,6 +632,7 @@ func makeJSONData(d *schema.ResourceData) gapi.JSONData {
 		DefaultBucket:              d.Get("json_data.0.default_bucket").(string),
 		DefaultProject:             d.Get("json_data.0.default_project").(string),
 		DefaultRegion:              d.Get("json_data.0.default_region").(string),
+		DerivedFields:              derivedFields,
 		Encrypt:                    d.Get("json_data.0.encrypt").(string),
 		EsVersion:                  d.Get("json_data.0.es_version").(string),
 		ExternalID:                 d.Get("json_data.0.external_id").(string),
@@ -601,6 +643,7 @@ func makeJSONData(d *schema.ResourceData) gapi.JSONData {
 		LogMessageField:            d.Get("json_data.0.log_message_field").(string),
 		MaxConcurrentShardRequests: int64(d.Get("json_data.0.max_concurrent_shard_requests").(int)),
 		MaxIdleConns:               int64(d.Get("json_data.0.max_idle_conns").(int)),
+		MaxLines:                   d.Get("json_data.0.max_lines").(int),
 		MaxOpenConns:               int64(d.Get("json_data.0.max_open_conns").(int)),
 		Organization:               d.Get("json_data.0.organization").(string),
 		OrgSlug:                    d.Get("json_data.0.org_slug").(string),

grafana/resource_data_source_test.go

@@ -22,6 +22,61 @@ func TestAccDataSource_basic(t *testing.T) {
 		attrChecks       map[string]string
 		additionalChecks []resource.TestCheckFunc
 	}{
+		{
+			resource: "grafana_data_source.loki",
+			config: `
+		resource "grafana_data_source" "tempo" {
+			name = "Tempo Linked to Loki"
+			type = "tempo"
+		}
+
+		resource "grafana_data_source" "loki" {
+			type                = "loki"
+			name                = "loki"
+			url                 = "http://acc-test.invalid/"
+			json_data {
+				max_lines = 2022
+
+				derived_field {
+					name = "WithoutDatasource"
+					matcher_regex = "(?:traceID|trace_id)=(\\w+)"
+					url = "example.com/$${__value.raw}"
+				}
+
+				derived_field {
+					name = "WithDatasource"
+					matcher_regex = "(?:traceID|trace_id)=(\\w+)"
+					url = "$${__value.raw}"
+					datasource_uid = grafana_data_source.tempo.uid
+				}
+			}
+		}
+		`,
+			attrChecks: map[string]string{
+				"type":                             "loki",
+				"name":                             "loki",
+				"url":                              "http://acc-test.invalid/",
+				"json_data.0.max_lines":            "2022",
+				"json_data.0.derived_field.0.name": "WithoutDatasource",
+				"json_data.0.derived_field.0.matcher_regex": "(?:traceID|trace_id)=(\\w+)",
+				"json_data.0.derived_field.0.url":           "example.com/${__value.raw}",
+				"json_data.0.derived_field.1.name":          "WithDatasource",
+				"json_data.0.derived_field.1.matcher_regex": "(?:traceID|trace_id)=(\\w+)",
+				"json_data.0.derived_field.1.url":           "${__value.raw}",
+			},
+			additionalChecks: []resource.TestCheckFunc{
+				func(s *terraform.State) error {
+					// Check datasource IDs
+					if dataSource.JSONData.DerivedFields[0].DatasourceUID != "" {
+						return fmt.Errorf("expected empty datasource_uid")
+					}
+					if !uidRegexp.MatchString(dataSource.JSONData.DerivedFields[1].DatasourceUID) {
+						return fmt.Errorf("expected valid datasource_uid")
+					}
+					return nil
+				},
+			},
+		},
 		{
 			resource: "grafana_data_source.testdata",
 			config: `