Invalid json format, please check. Reason: invalid character 'a' looking for beginning of object key string

Question

could you please assist me here? I have validated JSON but the issue appears.. also the strange thing is that when I create the JSON file with the wizard the issue does not appear. Thank you in advance.

Validate JSON:

{
    "agent": {
        "metrics_collection_interval": 60,
        "run_as_user": "root"
    },
    "logs": {
        "logs_collected": {
            "files": {
                "collect_list": [
                    {
                        "file_path": "/var/log/messages",
                        "log_group_name": "messages",
                        "log_stream_name": "{instance_id}"
                    }
                ]
            }
        }
    },
    "metrics": {
        "append_dimensions": {
            "AutoScalingGroupName": "${aws:AutoScalingGroupName}",
            "ImageId": "${aws:ImageId}",
            "InstanceId": "${aws:InstanceId}",
            "InstanceType": "${aws:InstanceType}"
        },
        "metrics_collected": {
            "collectd": {
                "metrics_aggregation_interval": 60
            },
            "cpu": {
                "measurement": [
                    "cpu_usage_idle",
                    "cpu_usage_iowait",
                    "cpu_usage_user",
                    "cpu_usage_system"
                ],
                "metrics_collection_interval": 60,
                "totalcpu": false
            },
            "disk": {
                "measurement": [
                    "used_percent",
                    "inodes_free"
                ],
                "metrics_collection_interval": 60,
                "resources": [
                    "*"
                ]
            },
            "diskio": {
                "measurement": [
                    "io_time",
                    "write_bytes",
                    "read_bytes",
                    "writes",
                    "reads"
                ],
                "metrics_collection_interval": 60,
                "resources": [
                    "*"
                ]
            },
            "mem": {
                "measurement": [
                    "mem_used_percent"
                ],
                "metrics_collection_interval": 60
            },
            "netstat": {
                "measurement": [
                    "tcp_established",
                    "tcp_time_wait"
                ],
                "metrics_collection_interval": 60
            },
            "statsd": {
                "metrics_aggregation_interval": 60,
                "metrics_collection_interval": 10,
                "service_address": ":8125"
            },
            "swap": {
                "measurement": [
                    "swap_used_percent"
                ],
                "metrics_collection_interval": 60
            }
        }
    }
}

sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a append-config -m ec2 -c file:/opt/aws/amazon-cloudwatch-agent/bin/config.json -s /opt/aws/amazon-cloudwatch-agent/bin/config-downloader --output-dir /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d --download-source file:/opt/aws/amazon-cloudwatch-agent/bin/config.json --mode ec2 --config /opt/aws/amazon-cloudwatch-agent/etc/common-config.toml --multi-config append Successfully fetched the config and saved in /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_config.json.tmp Start configuration validation... /opt/aws/amazon-cloudwatch-agent/bin/config-translator --input /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json --input-dir /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d --output /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml --mode ec2 --config /opt/aws/amazon-cloudwatch-agent/etc/common-config.toml --multi-config append

2019/08/26 07:58:17 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json ...
/opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json does not exist or cannot read. Skipping it.
2019/08/26 07:58:17 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/default ...
2019/08/26 07:58:17 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_config.json.tmp ...
2019/08/26 07:58:17 Invalid json format, please check. Reason: invalid character 'a' looking for beginning of object key string 
2019/08/26 07:58:17 I! AmazonCloudWatchAgent Version 1.223987.0.
2019/08/26 07:58:17 Configuration validation first phase failed. Agent version: 1.223987.0. Verify the JSON input is only using features supported by this version.

Answer 1

I managed to fix the java error this by adding \\ in front of the $. Then there was a terraform error message when I used terraform apply and added a second dollar sign to skip the interpolation.

"AutoScalingGroupName": "\$${aws:AutoScalingGroupName}",
"ImageId": "\$${aws:ImageId}",
"InstanceId": "\$${aws:InstanceId}",
"InstanceType": "\$${aws:InstanceType}"

Hope this will help somebody in the future.