Pierre-Olivier Mercier
9d76a0a62a
Introduce a transport abstraction so observation providers can run either
locally or be delegated to a remote HTTP endpoint. When an admin sets the
"endpoint" option, the engine substitutes the local provider with an
HTTPObservationProvider that POSTs to {endpoint}/collect.
116 lines
4.1 KiB
Go
116 lines
4.1 KiB
Go
// This file is part of the happyDomain (R) project.
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// Copyright (c) 2020-2026 happyDomain
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// Authors: Pierre-Olivier Mercier, et al.
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//
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// This program is offered under a commercial and under the AGPL license.
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// For commercial licensing, contact us at <contact@happydomain.org>.
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//
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// For AGPL licensing:
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package checker
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import (
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"bytes"
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"context"
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"encoding/json"
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"fmt"
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"io"
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"net/http"
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"strings"
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"time"
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"git.happydns.org/happyDomain/model"
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)
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// httpClient is a shared client with a sensible timeout for remote checker
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// endpoints. The per-request context can shorten this further.
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var httpClient = &http.Client{
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Timeout: 30 * time.Second,
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}
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// maxErrorBodySize is the maximum number of bytes read from an error response
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// body to include in the error message.
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const maxErrorBodySize = 4096
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// HTTPObservationProvider is an ObservationProvider that delegates data
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// collection to a remote HTTP endpoint via POST /collect.
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type HTTPObservationProvider struct {
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observationKey happydns.ObservationKey
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endpoint string // base URL without trailing slash
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}
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// NewHTTPObservationProvider creates a new HTTP-backed observation provider.
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// endpoint is the base URL of the remote checker (e.g. "http://checker-ping:8080").
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func NewHTTPObservationProvider(key happydns.ObservationKey, endpoint string) *HTTPObservationProvider {
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return &HTTPObservationProvider{
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observationKey: key,
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endpoint: strings.TrimSuffix(endpoint, "/"),
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}
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}
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// Key returns the observation key this provider handles.
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func (p *HTTPObservationProvider) Key() happydns.ObservationKey {
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return p.observationKey
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}
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// Collect sends the observation request to the remote endpoint and returns
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// the raw JSON data. The returned value is a json.RawMessage which
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// ObservationContext.Get() will marshal without double-encoding.
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func (p *HTTPObservationProvider) Collect(ctx context.Context, opts happydns.CheckerOptions) (any, error) {
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reqBody := happydns.ExternalCollectRequest{
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Key: p.observationKey,
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Options: opts,
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}
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body, err := json.Marshal(reqBody)
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if err != nil {
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return nil, fmt.Errorf("HTTP provider %s: failed to marshal request: %w", p.observationKey, err)
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}
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url := p.endpoint + "/collect"
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httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
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if err != nil {
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return nil, fmt.Errorf("HTTP provider %s: failed to create request: %w", p.observationKey, err)
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}
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httpReq.Header.Set("Content-Type", "application/json")
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resp, err := httpClient.Do(httpReq)
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if err != nil {
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return nil, fmt.Errorf("HTTP provider %s: request failed: %w", p.observationKey, err)
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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respBody, _ := io.ReadAll(io.LimitReader(resp.Body, maxErrorBodySize))
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return nil, fmt.Errorf("HTTP provider %s: endpoint returned status %d: %s", p.observationKey, resp.StatusCode, string(respBody))
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}
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var result happydns.ExternalCollectResponse
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if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
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return nil, fmt.Errorf("HTTP provider %s: failed to decode response: %w", p.observationKey, err)
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}
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if result.Error != "" {
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return nil, fmt.Errorf("HTTP provider %s: remote error: %s", p.observationKey, result.Error)
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}
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if result.Data == nil {
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return nil, fmt.Errorf("HTTP provider %s: remote returned empty data", p.observationKey)
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}
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// Return json.RawMessage directly - it implements json.Marshaler,
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// so ObservationContext.Get() won't double-encode it.
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return result.Data, nil
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}
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