cairnobs/terraform/internal/provider/client.go

package provider

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"time"
)

// client is a thin HTTP client against api/dashboards.Handler's REST
// endpoints -- deliberately hand-rolled, not generated from an OpenAPI
// spec (none exists in this repo yet), the same "boring, well-
// understood" posture cli/cmd/cairnobsctl's own httpclient.go already
// takes against the same API. Kept separate from that package (not
// reused directly) since this one needs typed request/response
// marshaling for Terraform's plan/state model, where cairnobsctl only
// ever needs to pretty-print whatever JSON comes back.
type client struct {
	baseURL string
	token   string
	http    *http.Client
}

func newClient(baseURL, token string) *client {
	return &client{baseURL: baseURL, token: token, http: &http.Client{Timeout: 30 * time.Second}}
}

// apiError carries the HTTP status code through so callers can
// distinguish "the server rejected this request" from "this specific
// resource doesn't exist" (isNotFound below) -- Read/Delete need that
// distinction to implement Terraform's standard "drop from state, don't
// error the whole apply" convention for a resource deleted out-of-band.
type apiError struct {
	StatusCode int
	Message    string
}

func (e *apiError) Error() string {
	return fmt.Sprintf("cairnobs api: request failed with status %d: %s", e.StatusCode, e.Message)
}

func isNotFound(err error) bool {
	var apiErr *apiError
	return errors.As(err, &apiErr) && apiErr.StatusCode == http.StatusNotFound
}

// dashboard mirrors api/dashboards.Dashboard's JSON shape -- deliberately
// a local type, not an import of that package (this module has no
// dependency on /api at all, matching every other cross-module boundary
// in this repo: talk over HTTP, not Go imports, to a service that isn't
// yours). Panels is populated by GET /dashboards/{id} (used by
// getPanel below, since panels have no GET endpoint of their own) but
// deliberately not settable through this type on create/update --
// panelResource manages panels one at a time through their own
// endpoints, never by rewriting a dashboard's whole panel list, so
// there's no code path that would ever marshal this field outbound.
type dashboard struct {
	ID              string  `json:"id,omitempty"`
	TenantID        string  `json:"tenant_id,omitempty"`
	Name            string  `json:"name"`
	Description     string  `json:"description"`
	DefaultEarliest string  `json:"default_earliest,omitempty"`
	DefaultLatest   string  `json:"default_latest,omitempty"`
	CreatedBy       string  `json:"created_by,omitempty"`
	CreatedAt       string  `json:"created_at,omitempty"`
	UpdatedAt       string  `json:"updated_at,omitempty"`
	Panels          []panel `json:"panels,omitempty"`
}

// panel mirrors api/dashboards.Panel's JSON shape. query_language
// deliberately never accepts "sql" -- api/dashboards's own
// validatePanel rejects it outright ("dashboards only support
// pipe-syntax queries, since the dashboard time-range picker is
// injected as leading query terms"), a real constraint this client
// doesn't re-validate client-side (same "let the API be the one source
// of truth for validation" posture the other resources already take),
// but is worth knowing about before hitting it as a 400 from Create.
type panel struct {
	ID               string          `json:"id,omitempty"`
	DashboardID      string          `json:"dashboard_id,omitempty"`
	Title            string          `json:"title"`
	Query            string          `json:"query"`
	QueryLanguage    string          `json:"query_language"`
	VizType          string          `json:"viz_type"`
	VizConfig        json.RawMessage `json:"viz_config,omitempty"`
	PositionX        int             `json:"position_x"`
	PositionY        int             `json:"position_y"`
	Width            int             `json:"width"`
	Height           int             `json:"height"`
	EarliestOverride *string         `json:"earliest_override,omitempty"`
	LatestOverride   *string         `json:"latest_override,omitempty"`
	SortOrder        int             `json:"sort_order"`
	CreatedAt        string          `json:"created_at,omitempty"`
	UpdatedAt        string          `json:"updated_at,omitempty"`
}

func (c *client) do(ctx context.Context, method, path string, body, out any) error {
	var reqBody io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			return fmt.Errorf("encoding request body: %w", err)
		}
		reqBody = bytes.NewReader(b)
	}
	req, err := http.NewRequestWithContext(ctx, method, c.baseURL+path, reqBody)
	if err != nil {
		return fmt.Errorf("building request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	if c.token != "" {
		req.Header.Set("Authorization", "Bearer "+c.token)
	}

	resp, err := c.http.Do(req)
	if err != nil {
		return fmt.Errorf("sending request: %w", err)
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("reading response: %w", err)
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		msg := string(respBody)
		var errResp struct {
			Error string `json:"error"`
		}
		if json.Unmarshal(respBody, &errResp) == nil && errResp.Error != "" {
			msg = errResp.Error
		}
		return &apiError{StatusCode: resp.StatusCode, Message: msg}
	}
	if out == nil || len(respBody) == 0 {
		return nil
	}
	if err := json.Unmarshal(respBody, out); err != nil {
		return fmt.Errorf("decoding response: %w", err)
	}
	return nil
}

func (c *client) createDashboard(ctx context.Context, d *dashboard) (*dashboard, error) {
	var out dashboard
	if err := c.do(ctx, http.MethodPost, "/dashboards", d, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) getDashboard(ctx context.Context, id string) (*dashboard, error) {
	var out dashboard
	if err := c.do(ctx, http.MethodGet, "/dashboards/"+id, nil, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) updateDashboard(ctx context.Context, id string, d *dashboard) (*dashboard, error) {
	var out dashboard
	if err := c.do(ctx, http.MethodPut, "/dashboards/"+id, d, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) deleteDashboard(ctx context.Context, id string) error {
	return c.do(ctx, http.MethodDelete, "/dashboards/"+id, nil, nil)
}

// rule mirrors alerting/internal/rulestore.Rule's JSON shape, plus the
// request-only `enabled` field POST /rules accepts
// (httpapi.createRuleRequest embeds rulestore.Rule and adds this
// pointer specifically so "omitted" (defaults to enabled) and
// "explicitly false" are distinguishable -- see handleCreateRule's doc
// comment) -- deliberately a local type, not an import of either
// package, same "talk HTTP, not Go imports, to a service that isn't
// yours" posture as dashboard above. GET/POST /rules both return this
// shape flattened (no separate "state" wrapper needed here since this
// resource doesn't manage or expose alert_state -- see the provider
// README on why).
type rule struct {
	ID                      string   `json:"id,omitempty"`
	TenantID                string   `json:"tenant_id,omitempty"`
	Name                    string   `json:"name"`
	Description             string   `json:"description"`
	Query                   string   `json:"query"`
	QueryLanguage           string   `json:"query_language"`
	ConditionType           string   `json:"condition_type"`
	Comparator              *string  `json:"comparator,omitempty"`
	ThresholdValue          *float64 `json:"threshold_value,omitempty"`
	EvalIntervalSeconds     int      `json:"eval_interval_seconds"`
	ForMinutes              int      `json:"for_minutes"`
	RenotifyIntervalMinutes *int     `json:"renotify_interval_minutes,omitempty"`
	NotificationTargetID    string   `json:"notification_target_id"`
	Enabled                 *bool    `json:"enabled,omitempty"`
	CreatedBy               string   `json:"created_by,omitempty"`
}

// createRule and getRule are the only mutating/reading calls this
// client makes against /rules -- there is deliberately no updateRule:
// alerting/internal/httpapi has no PUT /rules/{id} at all (confirmed
// down to rulestore.Store, which has Create/List/Get/Delete but no
// Update method to even wire one to) -- a real, pre-existing gap in
// alerting's own API, not something this provider works around by
// faking an update via delete+recreate under the hood. alertRuleResource
// models this honestly: every attribute is RequiresReplace, so
// Terraform destroys and recreates on any change rather than pretending
// an in-place update exists.
func (c *client) createRule(ctx context.Context, r *rule) (*rule, error) {
	var out rule
	if err := c.do(ctx, http.MethodPost, "/rules", r, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) getRule(ctx context.Context, id string) (*rule, error) {
	var out rule
	if err := c.do(ctx, http.MethodGet, "/rules/"+id, nil, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) deleteRule(ctx context.Context, id string) error {
	return c.do(ctx, http.MethodDelete, "/rules/"+id, nil, nil)
}

// notificationTarget mirrors alerting/internal/notifystore.Target's
// JSON shape -- deliberately a local type, same "talk HTTP, not Go
// imports" posture as dashboard/rule above. Headers is left as raw
// JSON bytes (not decoded into a Go map) since this client has no
// opinion about its shape -- alerting's own Target type doesn't either
// (json.RawMessage), and the resource layer round-trips it as a plain
// JSON-text string a caller provides via Terraform's jsonencode().
//
// Secret genuinely comes back from GET/List unredacted -- confirmed in
// notifystore/store.go's Get/List queries, which select the secret
// column with no redaction at either the store or handler layer. This
// is alerting's own existing behavior, not something this provider
// introduces or could fix from the client side; notificationTargetResource
// marks the corresponding attribute Sensitive so Terraform at least
// doesn't print it in plan/apply console output (it is still stored in
// Terraform state in plaintext -- a standard, disclosed Terraform
// limitation for any sensitive attribute, not specific to this one).
type notificationTarget struct {
	ID              string          `json:"id,omitempty"`
	TenantID        string          `json:"tenant_id,omitempty"`
	Name            string          `json:"name"`
	Kind            string          `json:"kind"`
	WebhookURL      string          `json:"webhook_url"`
	PayloadTemplate *string         `json:"payload_template,omitempty"`
	Headers         json.RawMessage `json:"headers,omitempty"`
	Secret          *string         `json:"secret,omitempty"`
	CreatedBy       string          `json:"created_by,omitempty"`
}

// createNotificationTarget and getNotificationTarget are the only
// mutating/reading calls this client makes against /targets -- same
// "no updateX method, alerting has no PUT /targets/{id} either" shape
// as rules above (rulestore.Store/notifystore.Store both only have
// Create/List/Get/Delete). notificationTargetResource is create/destroy
// only for the same reason alertRuleResource is.
func (c *client) createNotificationTarget(ctx context.Context, t *notificationTarget) (*notificationTarget, error) {
	var out notificationTarget
	if err := c.do(ctx, http.MethodPost, "/targets", t, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) getNotificationTarget(ctx context.Context, id string) (*notificationTarget, error) {
	var out notificationTarget
	if err := c.do(ctx, http.MethodGet, "/targets/"+id, nil, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) deleteNotificationTarget(ctx context.Context, id string) error {
	return c.do(ctx, http.MethodDelete, "/targets/"+id, nil, nil)
}

// createPanel, updatePanel, and deletePanel are straightforward --
// unlike rules/targets, api/dashboards.Handler actually has a
// PUT /dashboards/{id}/panels/{panelId}, so panelResource supports a
// real in-place update, the same as dashboardResource does.
func (c *client) createPanel(ctx context.Context, dashboardID string, p *panel) (*panel, error) {
	var out panel
	if err := c.do(ctx, http.MethodPost, "/dashboards/"+dashboardID+"/panels", p, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) updatePanel(ctx context.Context, dashboardID, panelID string, p *panel) (*panel, error) {
	var out panel
	if err := c.do(ctx, http.MethodPut, "/dashboards/"+dashboardID+"/panels/"+panelID, p, &out); err != nil {
		return nil, err
	}
	return &out, nil
}

func (c *client) deletePanel(ctx context.Context, dashboardID, panelID string) error {
	return c.do(ctx, http.MethodDelete, "/dashboards/"+dashboardID+"/panels/"+panelID, nil, nil)
}

// getPanel has no direct endpoint to call -- api/dashboards.Handler
// never registered a GET /dashboards/{id}/panels/{panelId}, only
// GET /dashboards/{id} (which includes the full panels list). This
// fetches the parent dashboard and finds the panel by ID within it,
// returning the same *apiError{StatusCode: 404} shape a direct GET
// would if either the dashboard itself or the panel within it is gone
// -- isNotFound works identically for callers regardless of which case
// applies, so panelResource's Read doesn't need to know the difference.
func (c *client) getPanel(ctx context.Context, dashboardID, panelID string) (*panel, error) {
	d, err := c.getDashboard(ctx, dashboardID)
	if err != nil {
		return nil, err
	}
	for i := range d.Panels {
		if d.Panels[i].ID == panelID {
			return &d.Panels[i], nil
		}
	}
	return nil, &apiError{StatusCode: http.StatusNotFound, Message: fmt.Sprintf("panel %q not found on dashboard %q", panelID, dashboardID)}
}