Every deployment has its own build log: the output of fetching your source, installing dependencies and running the build. Read it to find out why a build failed. Your app's output once it runs is in the runtime logs.
Open a build log
- Open the project's Deployments tab.
- Click a deployment.
The log loads under the deployment's details. While the deployment is still running, new output appears about once a second until it finishes. A finished deployment's log is saved, so you can open it again later, for failed and cancelled deployments too.
Lines that mention an error, a failure or a warning are highlighted, which makes the first error easier to spot. For a failed deployment, HCode's diagnosis is shown above the log; Build failures explains each one.
What the log hides
HCode replaces some values before the log is stored, so they never appear in it:
| Value | Shown as |
|---|---|
| The value of each environment variable passed to an automatic build, if it is 4 characters or longer | [redacted:NAME], with the variable's name |
| Your repository's address | [repository] |
| The commit hash being built | [commit] |
The dashboard also hides GitHub access tokens, bearer tokens and api_key= or token= values in the lines it shows, as [REDACTED].
Values shorter than 4 characters are not replaced, and neither is anything your build prints that isn't one of these values. Don't print secrets from your build scripts.
An automatic build also writes the names of any environment variables it didn't pass to the build. See Environment variables.
Size limit
A build log stores at most 10 MB of output. Anything a build prints after that is dropped.