feat: Add Linear integration

docs/components/Linear.mdx

@@ -0,0 +1,155 @@
+---
+title: "Linear"
+---
+
+Manage and react to issues in Linear
+
+## Triggers
+
+<CardGrid>
+  <LinkCard title="On Issue" href="#on-issue" description="Start a workflow when an issue is created, updated, or removed in Linear" />
+</CardGrid>
+
+import { CardGrid, LinkCard } from "@astrojs/starlight/components";
+
+## Actions
+
+<CardGrid>
+  <LinkCard title="Create Issue" href="#create-issue" description="Create a new issue in Linear" />
+</CardGrid>
+
+## Instructions
+
+Leave **Client ID** and **Client Secret** empty to start the setup wizard.
+
+<a id="on-issue"></a>
+
+## On Issue
+
+The On Issue trigger starts a workflow when an issue is created, updated, or removed in Linear.
+
+### Use Cases
+
+- **Issue automation**: Run workflows when issues change
+- **Notification workflows**: Notify channels or create tasks elsewhere
+- **Filter by team/label**: Optionally restrict to a team and/or labels
+
+### Configuration
+
+- **Team**: Optional. Select a team to listen to, or leave empty to listen to all public teams.
+- **Labels**: Optional. Only trigger when the issue has at least one of these labels.
+
+### Event Data
+
+The payload includes Linear webhook fields: action, type, data (issue), actor, url, createdAt, webhookTimestamp.
+The action field indicates the event type: "create", "update", or "remove".
+
+### Example Data
+
+```json
+{
+  "data": {
+    "action": "create",
+    "actor": {
+      "email": "[email protected]",
+      "id": "bd35d567-0f57-46fa-85e1-9b1e53529393",
+      "name": "superplane",
+      "type": "user",
+      "url": "https://linear.app/brainstormmingdev/profiles/superplane1"
+    },
+    "createdAt": "2026-02-16T21:35:23.762Z",
+    "data": {
+      "addedToTeamAt": "2026-02-16T21:35:23.788Z",
+      "botActor": null,
+      "createdAt": "2026-02-16T21:35:23.762Z",
+      "creatorId": "bd35d567-0f57-46fa-85e1-9b1e53529393",
+      "description": "test test",
+      "descriptionData": "{\"type\":\"doc\",\"content\":[{\"type\":\"paragraph\",\"content\":[{\"type\":\"text\",\"text\":\"test test\"}]}]}",
+      "id": "4aae5d23-07a5-4e68-912e-098dbf5a5b4e",
+      "identifier": "BRA-45",
+      "labelIds": [],
+      "labels": [],
+      "number": 45,
+      "previousIdentifiers": [],
+      "priority": 0,
+      "priorityLabel": "No priority",
+      "prioritySortOrder": -4135,
+      "reactionData": [],
+      "slaType": "all",
+      "sortOrder": -4029,
+      "state": {
+        "color": "#bec2c8",
+        "id": "af874731-64fd-4b3e-b871-b762922637b6",
+        "name": "Backlog",
+        "type": "backlog"
+      },
+      "stateId": "af874731-64fd-4b3e-b871-b762922637b6",
+      "subscriberIds": [
+        "bd35d567-0f57-46fa-85e1-9b1e53529393"
+      ],
+      "team": {
+        "id": "01d0cb17-f38a-4fea-9e5c-717dbb27766f",
+        "key": "BRA",
+        "name": "BrainStormmingDev"
+      },
+      "teamId": "01d0cb17-f38a-4fea-9e5c-717dbb27766f",
+      "title": "Test superplane",
+      "updatedAt": "2026-02-16T21:35:23.762Z",
+      "url": "https://linear.app/brainstormmingdev/issue/BRA-45/test-superplane"
+    },
+    "type": "Issue",
+    "url": "https://linear.app/brainstormmingdev/issue/BRA-45/test-superplane",
+    "webhookTimestamp": 1771277724034
+  },
+  "timestamp": "2026-02-16T21:35:22.388339184Z",
+  "type": "linear.issue"
+}
+```
+
+<a id="create-issue"></a>
+
+## Create Issue
+
+The Create Issue component creates a new issue in Linear.
+
+### Use Cases
+
+- **Task creation**: Automatically create issues from workflow events
+- **Bug tracking**: Create issues from alerts or external systems
+- **Feature requests**: Generate issues from forms or other triggers
+
+### Configuration
+
+- **Team**: The Linear team to create the issue in
+- **Title**: Issue title (required)
+- **Description**: Optional description
+- **Assignee**, **Labels**, **Priority**, **Status**: Optional
+
+### Output
+
+Returns the created issue: id, identifier, title, description, priority, url, createdAt.
+
+### Example Output
+
+```json
+{
+  "data": {
+    "createdAt": "2026-02-16T21:35:23.762Z",
+    "description": "test test",
+    "id": "4aae5d23-07a5-4e68-912e-098dbf5a5b4e",
+    "identifier": "BRA-45",
+    "priority": 0,
+    "state": {
+      "id": "af874731-64fd-4b3e-b871-b762922637b6"
+    },
+    "team": {
+      "id": "01d0cb17-f38a-4fea-9e5c-717dbb27766f"
+    },
+    "title": "Test superplane",
+    "url": "https://linear.app/brainstormmingdev/issue/BRA-45/test-superplane"
+  },
+  "timestamp": "2026-02-16T21:35:22.010159122Z",
+  "type": "linear.issue"
+}
+```
+

pkg/integrations/linear/auth.go

@@ -0,0 +1,129 @@
+package linear
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/superplanehq/superplane/pkg/core"
+)
+
+const (
+	linearAuthorizeURL = "https://linear.app/oauth/authorize"
+	linearTokenURL     = "https://api.linear.app/oauth/token"
+)
+
+type Auth struct {
+	client core.HTTPContext
+}
+
+func NewAuth(client core.HTTPContext) *Auth {
+	return &Auth{client: client}
+}
+
+type TokenResponse struct {
+	AccessToken  string `json:"access_token"`
+	RefreshToken string `json:"refresh_token"`
+	TokenType    string `json:"token_type"`
+	ExpiresIn    int    `json:"expires_in"`
+	Scope        string `json:"scope"`
+}
+
+func (t *TokenResponse) GetExpiration() time.Duration {
+	if t.ExpiresIn > 0 {
+		seconds := t.ExpiresIn / 2
+		if seconds < 1 {
+			seconds = 1
+		}
+		return time.Duration(seconds) * time.Second
+	}
+	return time.Hour
+}
+
+func (a *Auth) exchangeCode(clientID, clientSecret, code, redirectURI string) (*TokenResponse, error) {
+	data := url.Values{}
+	data.Set("grant_type", "authorization_code")
+	data.Set("client_id", clientID)
+	data.Set("client_secret", clientSecret)
+	data.Set("code", code)
+	data.Set("redirect_uri", redirectURI)
+	return a.postToken(data)
+}
+
+func (a *Auth) RefreshToken(clientID, clientSecret, refreshToken string) (*TokenResponse, error) {
+	data := url.Values{}
+	data.Set("grant_type", "refresh_token")
+	data.Set("client_id", clientID)
+	data.Set("client_secret", clientSecret)
+	data.Set("refresh_token", refreshToken)
+	return a.postToken(data)
+}
+
+func (a *Auth) postToken(data url.Values) (*TokenResponse, error) {
+	req, err := http.NewRequest(http.MethodPost, linearTokenURL, strings.NewReader(data.Encode()))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := a.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("token request failed: status %d, body: %s", resp.StatusCode, string(body))
+	}
+
+	var tokenResp TokenResponse
+	if err := json.Unmarshal(body, &tokenResp); err != nil {
+		return nil, err
+	}
+
+	return &tokenResp, nil
+}
+
+func (a *Auth) HandleCallback(req *http.Request, clientID, clientSecret, expectedState, redirectURI string) (*TokenResponse, error) {
+	code := req.URL.Query().Get("code")
+	state := req.URL.Query().Get("state")
+	errorParam := req.URL.Query().Get("error")
+
+	if errorParam != "" {
+		errorDesc := req.URL.Query().Get("error_description")
+		return nil, fmt.Errorf("OAuth error: %s - %s", errorParam, errorDesc)
+	}
+
+	if code == "" || state == "" {
+		return nil, fmt.Errorf("missing code or state")
+	}
+
+	if state != expectedState {
+		return nil, fmt.Errorf("invalid state")
+	}
+
+	return a.exchangeCode(clientID, clientSecret, code, redirectURI)
+}
+
+func findSecret(integration core.IntegrationContext, name string) (string, error) {
+	secrets, err := integration.GetSecrets()
+	if err != nil {
+		return "", err
+	}
+	for _, secret := range secrets {
+		if secret.Name == name {
+			return string(secret.Value), nil
+		}
+	}
+	return "", nil
+}