homelab/knecht/portainer/client.go

package portainer

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
)

type Client struct {
	baseURL    string
	token      string
	httpClient *http.Client
	endpointID int
}

type Endpoint struct {
	ID   int    `json:"Id"`
	Name string `json:"Name"`
}

type EnvVar struct {
	Name  string `json:"name"`
	Value string `json:"value"`
}

type Stack struct {
	ID         int      `json:"Id"`
	Name       string   `json:"Name"`
	Status     int      `json:"Status"` // 1 = active, 2 = inactive
	EndpointID int      `json:"EndpointId"`
	Env        []EnvVar `json:"Env"`
}

type StackFile struct {
	StackFileContent string `json:"StackFileContent"`
}

func New(baseURL, token, endpointName string) (*Client, error) {
	c := &Client{
		baseURL:    strings.TrimRight(baseURL, "/"),
		token:      token,
		httpClient: &http.Client{},
	}

	id, err := c.discoverEndpoint(endpointName)
	if err != nil {
		return nil, err
	}
	c.endpointID = id
	return c, nil
}

func (c *Client) EndpointID() int {
	return c.endpointID
}

func (c *Client) discoverEndpoint(name string) (int, error) {
	var endpoints []Endpoint
	if err := c.get("/api/endpoints", &endpoints); err != nil {
		return 0, fmt.Errorf("listing endpoints: %w", err)
	}
	if len(endpoints) == 0 {
		return 0, fmt.Errorf("no endpoints found in Portainer")
	}
	// If a name is specified, match by name; otherwise use the first active one.
	for _, e := range endpoints {
		if name == "" || e.Name == name {
			return e.ID, nil
		}
	}
	return 0, fmt.Errorf("endpoint %q not found", name)
}

func (c *Client) ListStacks() ([]Stack, error) {
	var stacks []Stack
	if err := c.get("/api/stacks", &stacks); err != nil {
		return nil, err
	}
	return stacks, nil
}

func (c *Client) GetStack(id int) (*Stack, error) {
	var s Stack
	if err := c.get(fmt.Sprintf("/api/stacks/%d", id), &s); err != nil {
		return nil, err
	}
	return &s, nil
}

func (c *Client) GetStackByName(name string) (*Stack, error) {
	stacks, err := c.ListStacks()
	if err != nil {
		return nil, err
	}
	for _, s := range stacks {
		if s.Name == name {
			return &s, nil
		}
	}
	return nil, nil // not found, not an error
}

func (c *Client) GetStackFile(id int) (string, error) {
	var f StackFile
	if err := c.get(fmt.Sprintf("/api/stacks/%d/file", id), &f); err != nil {
		return "", err
	}
	return f.StackFileContent, nil
}

func (c *Client) CreateStack(name, composeContent string, env []EnvVar) (*Stack, error) {
	body := map[string]any{
		"name":             name,
		"stackFileContent": composeContent,
		"env":              env,
	}
	var s Stack
	if err := c.post(fmt.Sprintf("/api/stacks/create/standalone/string?endpointId=%d", c.endpointID), body, &s); err != nil {
		return nil, err
	}
	return &s, nil
}

func (c *Client) UpdateStack(id int, composeContent string, env []EnvVar) (*Stack, error) {
	body := map[string]any{
		"stackFileContent": composeContent,
		"env":              env,
		"prune":            true,
		"pullImage":        false,
	}
	var s Stack
	if err := c.put(fmt.Sprintf("/api/stacks/%d?endpointId=%d", id, c.endpointID), body, &s); err != nil {
		return nil, err
	}
	return &s, nil
}

// request helpers

func (c *Client) get(path string, out any) error {
	resp, err := c.do("GET", path, nil)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return json.NewDecoder(resp.Body).Decode(out)
}

func (c *Client) post(path string, body, out any) error {
	resp, err := c.do("POST", path, body)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return json.NewDecoder(resp.Body).Decode(out)
}

func (c *Client) put(path string, body, out any) error {
	resp, err := c.do("PUT", path, body)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return json.NewDecoder(resp.Body).Decode(out)
}

func (c *Client) do(method, path string, body any) (*http.Response, error) {
	var bodyReader io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			return nil, err
		}
		bodyReader = bytes.NewReader(b)
	}

	req, err := http.NewRequest(method, c.baseURL+path, bodyReader)
	if err != nil {
		return nil, err
	}
	req.Header.Set("X-API-Key", c.token)
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode >= 400 {
		b, _ := io.ReadAll(resp.Body)
		resp.Body.Close()
		return nil, fmt.Errorf("portainer API %s %s: %s — %s", method, path, resp.Status, string(b))
	}
	return resp, nil
}