dotcloud/docker

package middleware // import "github.com/docker/docker/api/server/middleware"

import (
    "bufio"
    "context"
    "encoding/json"
    "io"
    "net/http"
    "strings"

    "github.com/containerd/log"
    "github.com/docker/docker/api/server/httpstatus"
    "github.com/docker/docker/api/server/httputils"
    "github.com/docker/docker/pkg/ioutils"
    "github.com/sirupsen/logrus"
)

// DebugRequestMiddleware dumps the request to logger
func DebugRequestMiddleware(handler func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error) func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
    return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) (retErr error) {
        logger := log.G(ctx)

        // Use a variable for fields to prevent overhead of repeatedly
        // calling WithFields.
        fields := log.Fields{
            "module":      "api",
            "method":      r.Method,
            "request-url": r.RequestURI,
            "vars":        vars,
            "status":      http.StatusOK,
        }
        defer func() {
            if retErr != nil {
                fields["error-response"] = retErr
                fields["status"] = httpstatus.FromError(retErr)
            }
            logger.WithFields(fields).Debugf("handling %s request", r.Method)
        }()

        if r.Method != http.MethodPost {
            return handler(ctx, w, r, vars)
        }
        if err := httputils.CheckForJSON(r); err != nil {
            return handler(ctx, w, r, vars)
        }
        maxBodySize := 4096 // 4KB
        if r.ContentLength > int64(maxBodySize) {
            return handler(ctx, w, r, vars)
        }

        body := r.Body
        bufReader := bufio.NewReaderSize(body, maxBodySize)
        r.Body = ioutils.NewReadCloserWrapper(bufReader, func() error { return body.Close() })

        b, err := bufReader.Peek(maxBodySize)
        if err != io.EOF {
            // either there was an error reading, or the buffer is full (in which case the request is too large)
            return handler(ctx, w, r, vars)
        }

        var postForm map[string]interface{}
        if err := json.Unmarshal(b, &postForm); err == nil {
            maskSecretKeys(postForm)
            // TODO(thaJeztah): is there a better way to detect if we're using JSON-formatted logs?
            if _, ok := logger.Logger.Formatter.(*logrus.JSONFormatter); ok {
                fields["form-data"] = postForm
            } else {
                if data, err := json.Marshal(postForm); err != nil {
                    fields["form-data"] = postForm
                } else {
                    fields["form-data"] = string(data)
                }
            }
        }

        return handler(ctx, w, r, vars)
    }
}

func maskSecretKeys(inp interface{}) {
    if arr, ok := inp.([]interface{}); ok {
        for _, f := range arr {
            maskSecretKeys(f)
        }
        return
    }

    if form, ok := inp.(map[string]interface{}); ok {
        scrub := []string{
            // Note: The Data field contains the base64-encoded secret in 'secret'
            // and 'config' create and update requests. Currently, no other POST
            // API endpoints use a data field, so we scrub this field unconditionally.
            // Change this handling to be conditional if a new endpoint is added
            // in future where this field should not be scrubbed.
            "data",
            "jointoken",
            "password",
            "secret",
            "signingcakey",
            "unlockkey",
        }
    loop0:
        for k, v := range form {
            for _, m := range scrub {
                if strings.EqualFold(m, k) {
                    form[k] = "*****"
                    continue loop0
                }
            }
            maskSecretKeys(v)
        }
    }
}