Published on Fri May 29 2026 17:20:00 GMT+0000 (Coordinated Universal Time) by Leo

How to Fix Docker Logs Error: invalid character ‘l’ after object key:value pair

When running docker logs or docker compose logs, you may see an error like this:

error from daemon in stream: Error grabbing logs: invalid character 'l' after object key:value pair

This is usually a Docker log reading error, not an exception thrown directly by your application code.

Quick fix: find the container log file with docker inspect, truncate the corrupted log file, then run docker logs again.

Why it happens

By default, Docker writes container stdout and stderr to a json-file log. Each log entry is expected to be one valid JSON object per line:

{"log":"...","stream":"stdout","time":"..."}

If one of those lines becomes corrupted, Docker can no longer parse the log file. Common causes include:

• A truncated log line
• Broken log rotation
• Interrupted disk writes
• Manual edits to the Docker log file
• Docker daemon issues
• A full or unstable disk

When Docker reaches the malformed line, docker logs fails while parsing the file and reports the invalid character error.

In most cases, the container is still running normally. The failure happens when Docker tries to parse its own json-file log.

Clear the corrupted log file

First, find the log file path for the affected container:

docker inspect -f '{{.LogPath}}' <container_id_or_name>

Then truncate the file:

sudo truncate -s 0 "$(docker inspect -f '{{.LogPath}}' <container_id_or_name>)"

After that, check the logs again:

docker logs <container_id_or_name>

This removes the corrupted log content but keeps the container itself.

Restart or recreate the container

If the container state is also abnormal, restart it:

docker restart <container_id_or_name>

For Docker Compose, recreating the container is also an option:

docker compose down
docker compose up -d

Be careful with docker compose down: it removes containers, but it does not remove named volumes by default. If important data is stored inside the container filesystem instead of a volume, back it up before recreating the container.

Prevent it with log rotation

To reduce the chance of oversized or corrupted log files, configure Docker log rotation:

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  }
}

This configuration is usually placed in:

/etc/docker/daemon.json

Restart Docker after changing it. Existing containers usually need to be recreated before the new logging configuration applies to them.

FAQ

Is this caused by my application?

Usually no. The application may have written normal stdout or stderr logs, but Docker fails because the json-file log is corrupted.

Will truncating the log file stop the container?

No. It only clears the stored Docker log file. The running container is not removed.

Written by Leo