Troubleshooting Source Maps

Source maps can sometimes be tricky to get going. If you’re having trouble:

Verify a release is configured in your SDK

For uploaded source maps to be located and applied, the release needs to be created by the CLI or API (and the correct artifacts uploaded with it), and the name of that newly-created release needs to be specified in your SDK configuration.

To verify this, open up the issue from the Sentry UI and check if the release is configured. If it says "not configured" or "N/A" next to Release on the right hand side of the screen (or if you do not see a release tag in the list of tags), you'll need to go back and tag your errors. If this is properly set up you'll see "Release: my_example_release".

Verify artifacts are uploaded

Once your release is properly configured and issues are tagged, you can find the artifacts uploaded to Sentry by navigating to [Project] » Project Settings » Source Maps.

Additionally, make sure all of the necessary files are available. For Sentry to de-minify your stack traces you must provide both the minified files (for example, app.min.js) and the corresponding source maps. In case the source map files do not contain your original source code (sourcesContent), you must additionally provide the original source files. Alternatively, sentry-cli will automatically embed the sources (if missing) into your source maps.

Verify sourceMappingURL is present

Some CDNs automatically strip comments from static files, including JavaScript files. This can have the effect of stripping your JavaScript file of its sourceMappingURL directive, because it is considered a comment. For example, CloudFlare has a feature called Auto-Minify which will strip sourceMappingURL if it is enabled.

Double-check that your deployed, final JavaScript files have sourceMappingURL present.

Alternately, instead of sourceMappingURL, you can set a SourceMap HTTP header on your minified file. If this header is present, Sentry will use it to discover the location of your source map.

Verify artifact distribution value matches value configured in your SDK

Whenever you are using a distribution identifier (the dist configuration option in the SDK), the same value has to be used during source map upload. Conversely, if your source maps are getting uploaded with a dist value, the same value must be set in your SDK. To add a dist value to your uploaded source maps, use the --dist flag with sentry-cli or the dist option with @sentry/webpack-plugin. To set the dist value in the SDK, use the dist option in your Sentry.init().

To verify that the distribution has been set correctly in the SDK, open an issue in the Sentry UI and check that the dist tag is present. For artifacts, go to the Source Maps page in project settings, choose the release shown on the event you just checked, and verify that the dist value (in the small oval next to the upload time) matches that on the event.

Verify artifact names match stack trace frames

If you’ve uploaded source maps and they aren’t applying to your code in an issue in Sentry, take a look at the JSON of the event and look for the abs_path to see exactly where we’re attempting to resolve the file - for example, http://localhost:8000/scripts/script.js (abs_path will appear once for each frame in the stack trace - match this up with the file(s) that are not deminified.). A link to the JSON view can be found at the top of the issue page next to the date the event occurred. The uploaded artifact names must match these values.

If you have dynamic values in your path (for example, https://www.site.com/{some_value}/scripts/script.js), you may want to use the rewriteFrames integration to change your abs_path values.

Using sentry-cli

If your sourceMappingURL comment is similar to:

// -- end script.min.js (located at http://localhost:8000/scripts/script.min.js)
//# sourceMappingURL=script.min.js.map

An example sentry-cli command to upload these files correctly would look like this (assuming you’re in the /scripts directory, running your web server from one directory higher, which is why we’re using the --url-prefix option):

sentry-cli releases files VERSION upload-sourcemaps . --url-prefix '~/scripts'

This command uploads all JavaScript files in the current directory. The Artifacts page in Sentry should now look like:

~/scripts/script.js
~/scripts/script.min.js
~/scripts/script.min.js.map

Alternately you can specify which files to upload. For example:

sentry-cli releases files VERSION upload-sourcemaps script.min.js script.min.js.map --url-prefix '~/scripts'

You can also upload it with the fully qualified URL. For example:

sentry-cli releases files VERSION upload-sourcemaps . --url-prefix 'http://localhost:8000/scripts'

Using the API

You can alternately use our API to upload artifacts, following the same naming convention explained here.

curl -X POST \
  https://sentry.io/api/0/organizations/ORG_SLUG/releases/VERSION/files/ \
  -H 'Authorization: Bearer AUTH_TOKEN' \
  -H 'content-type: multipart/form-data' \
  -F file=@script.min.js.map \
  -F 'name=~/scripts/script.min.js.map'

Using the ~

The ~ is used in Sentry to replace the scheme and domain. It is not a glob!

http://example.com/dist/js/script.js will match ~/dist/js/script.js or http://example.com/dist/js/script.js

but will NOT match ~/script.js.

Verify artifact names match sourceMappingURL value

The sourceMappingURL comment on the last line of your bundled or minified JavaScript file tells Sentry (or the browser) where to locate the corresponding source map. This can either be a fully qualified URL, a relative path, or the filename itself. When uploading artifacts to Sentry, you must name your source map files with the value the file resolves to.

That is, if your file is similar to:

// -- end script.min.js
//# sourceMappingURL=script.min.js.map

and is hosted at http://example.com/js/script.min.js, then Sentry will look for that source map file at http://example.com/js/script.min.js.map. Your uploaded artifact must therefore be named http://example.com/js/script.min.js.map (or ~/js/script.min.js.map).

Or, if your file is similar to:

//-- end script.min.js
//# sourceMappingURL=https://example.com/dist/js/script.min.js.map

then your uploaded artifact should also be named https://example.com/dist/js/script.min.js.map (or ~/dist/js/script.min.js.map).

Finally, if your file is similar to:

//-- end script.min.js
//# sourceMappingURL=../maps/script.min.js.map

then your uploaded artifact should be named https://example.com/dist/maps/script.min.js.map (or ~/dist/maps/script.min.js.map).

Verify artifacts are uploaded before errors occur

Sentry expects that source code and source maps in a given release are uploaded to Sentry before errors occur in that release.

If you upload artifacts after an error is captured by Sentry, Sentry will not go back and retroactively apply any source annotations to those errors. Only new errors triggered after the artifact was uploaded will be affected.

Verify your source maps are built correctly

We maintain an online validation tool that can be used to test your source maps against your hosted source: sourcemaps.io.

Alternatively, if you are using Sentry CLI to upload source maps to Sentry, you can use the --validate command line option to verify your source maps are correct.

Verify your source maps work locally

If you find that Sentry is not mapping filename, line, or column mappings correctly, you should verify that your source maps are functioning locally. To do so, you can use Node.js coupled with Mozilla’s source-map library.

First, install source-map globally as an npm module:

npm install -g source-map

Then, write a script that reads your source map file and tests a mapping. Here’s an example:

var fs = require("fs"),
  path = require("path"),
  sourceMap = require("source-map");

// file output by Webpack, Uglify, and so forth
var GENERATED_FILE = path.join(".", "app.min.js.map");

// line and column located in your generated file (for example, the source of your error
// from your minified file)
var GENERATED_LINE_AND_COLUMN = { line: 1, column: 1000 };

var rawSourceMap = fs.readFileSync(GENERATED_FILE).toString();
new sourceMap.SourceMapConsumer(rawSourceMap).then(function(smc) {
  var pos = smc.originalPositionFor(GENERATED_LINE_AND_COLUMN);

  // should see something like:
  // { source: 'original.js', line: 57, column: 9, name: 'myfunc' }
  console.log(pos);
});

If you have the same (incorrect) results locally as you do via Sentry, double-check your source map generation configuration.

Verify your source files are not too large

For an individual artifact, Sentry accepts a max filesize of 40 MB.

Often users hit this limit because they are transmitting source files at an interim build stage. For example, after Webpack/Browserify has combined all your source files, but before minification has taken place. If possible, send the original source files.

Verify artifacts are not gzipped

The Sentry API currently only works with source maps and source files that are uploaded as plain text (UTF-8 encoded). If the files are uploaded in a compressed format (for example, gzip), they will be not be interpreted correctly.

This sometimes occurs with build scripts and plugins that produce pre-compressed minified files. For example, Webpack’s compression plugin. You’ll need to disable such plugins and perform the compression after the generated source maps/source files have been uploaded to Sentry.

Verify workers are sharing the same volume as web (if running self-hosted Sentry via Docker)

Sentry does source map calculation in its workers. This means the workers need access to the files uploaded through the front end. Double check that the cron workers and web workers can read/write files from the same disk.