# Grafana@ctrend.xfel.eu

Contents:

## Accessing ctrend.xfel.eu

European XFEL staff can access ctrend.xfel.eu using their regular credentials.

Note

General acccess to ctrend.xfel.eu does not automatically authorize you to view or possibly edit the content. Which content you can access depends on the teams you are a member of.

## Teams and Authorization

Permissions to view and edit content on the Grafana installation at ctrend.xfel.eu are controlled through a combination of so-called teams and folders:

Folders: | folders group dashboards and panels into areas of similar contents. Folders exist e.g. for each instrument, or for general topics such as detectors, photon diagnostics, or vacuum. Multiple XFEL groups may be responsible for curating the content of a folder.
Teams: | a team is a group of users which should have the same minimum access level to a Folder. Hence, teams are assigned to Folders with e.g. view-only, or editor access. A given user can be member of multiple teams, and multiple teams may be authorized to access a folder.

For the ctrend.xfel.eu installation teams generally map to the folder structure: there are at least two teams configured to access each folder:

View-only teams:
| users in these teams can view the content, i.e. the dashboards and contents of a folder. They cannot edit existing dashboards, nor can they create new ones. Modification of dates and times to be accessed is possible, but cannot be persisted. Data can be exported, e.g. to CSV.
Editor teams: | users in these teams can view the content, i.e. the dashboards and contents of a folder. In addition, they can create new dashboards and panels within the folder the team is assigned to, change date and times a dashboard or panel shows, and also persist this change as the default view. Users can modify existing dashboards and panels, and edit e.g. graphing option. Data can be exported, e.g. to CSV.

Note

Teams do not strictly relate to XFEL groups: a SPB scientist wanting to view a panel in the MID folder would be added to the MID view-only team to do so.

Note

Privileges on folders are assigned to Teams by CTRL, and team editors cannot change them. However, the association of Teams to Folders is not expected to change frequently. Users should be added to a team already assigned to a given folder, rather than assigning a new team, and thus many users to that folder.

Folders at ctrend.xfel.eu and team access to them. View-only teams always have the suffix -view-only, even if not indicated in the table. SUPPORT contains alls teams from the DATA and instrumentation departments. ALL contains all teams.
Folder | View-only teams | Editor teams
--- | --- | ---
FXE | FXE-view-only, SUPPORT | FXE, CTRL
SPB | SPB-view-only, SUPPORT | SPB, CTRL
MID | MID-view-only, SUPPORT | MID, CTRL
HED | HED-view-only, SUPPORT | HED, CTRL
SCS | SCS-view-only, SUPPORT | SCS, CTRL
SQS | SQS-view-only, SUPPORT | SQS, CTRL
SASE1 | ALL | VAC, XPD, BKR, CTRL, EEE, XRO
SASE2 | ALL | VAC, XPD, BKR, CTRL, EEE, XRO
SASE3 | ALL | VAC, XPD, BKR, CTRL, EEE, XRO
Beckhoff | SUPPORT | EEE, CTRL
Calibration | SUPPORT | DET, DA, CAL, CTRL
Cameras | SUPPORT | DET, DA, CAL, CTRL
DAQ | SUPPORT | ITDM, CTRL
Data Analysis | SUPPORT | DA, CTRL
Detectors | SUPPORT | DET, CTRL
Lasers | SUPPORT | LAS, EEE, CTRL
Photon Diagnostics | SUPPORT | XPD, CTRL
Timing | SUPPORT | EEE, CTRL
Vacuum | SUPPORT | VAC, CTRL
X-ray operations | ALL? | XO, CTRL

### Team Administration

For each team at least one priviledged user exists, who can administer the team through the ctrend.xfel.eu interface. Specifically, this user can add new members to the team. Usually, the priviledged users will be the same for both the view-only and editor teams of a given folder.

Note

Staff wishing to view the content of a folder should contact these priviledged users to be granted access.

Please see the table below, for who administers which folder.

Folders at ctrend.xfel.eu and corresponding priviledged users.
Folder | View-only team | Editor team
--- | --- | ---
FXE |  |
SPB |  |
MID |  |
HED |  |
SCS |  |
SQS |  |
SASE1 |  |
SASE2 |  |
SASE3 |  |
Beckhoff | Hauf
Calibration |  |
Cameras | Hauf
DAQ |  |
Data Analysis |  |
Detectors |  |
Lasers |  |
Photon Diagnostics |  |
Timing | Hauf
Vacuum |  |
Xray-Operations |  |

If you are a priviledged user see Administering a Team for how to add users to a team.

### Support Group Teams

Staff from the DATA and instrumentation department groups will be placed into teams named after their groups. These teams are administratored by priviledged users from the group and should only contain members from the group. These teams will be authorized to minimally view, and in case of need, edit all folders, such as to provide efficient support.

## Dashboards

In Grafana, Dashboards are screens which aggregrate multiple :ref:`panels`_ into logical views. Detailed information on dashboards can be found in the Grafana documentation: https://grafana.com/docs/grafana/latest/features/dashboard/dashboards/. Here we will only give a short introduction on examples how Dashboards are used in the ctrend.xfel.eu context.

Note

Depending on your access rights for a given folder you may not be able to execute or view some of the actions and features described in this section.

### Organizing Content via Dashboards

Dashboards are foreseen to be the usual way of grouping related information (panels) within each Team’s folder. As such it is advised that they are given meaningful names, e.g. relating to a certain components, or component types: PP Lasers, Cameras, XGM, … .

### Dashboard Layout

Dashboards organize content on a row x column grid. While you can add rows such that scrolling is necessary, keep in mind that you might want to display a Dashboard on overview screens in the hutches and control rooms. Here you likely want everything in view - without scrolling. Check for instance if multiple data sources can be aggregated in the same panel, or if organizing content over multiple dashboarsd may make sense.

### Dashboard Variables

At the European XFEL many components are implemented in standardized ways. Hence you will find very similar devices in Karabo for different instruments, or in different component groups. Dashboard variables allow you to parameterize panels, by variables which can be entered on a dashboards. This allows you to use a single panel to display data from similar data sources.

An example of such usage is the parameterization of the general overview dashboards and panels on the Karabo topics, as shown below.

Here the variable refers to different data sources which are then used in the panel to query information for.

Variables can also be used to parameterize e.g. device names.

To create a variable for a dashboard, click on the gears symbol to access the dashboard settings.

Then click on “Variables” and “New”. You should now see a screen similar to the following:

The important fields to edit in this dialog are:

Name: | give a name to the variable. This is also the parameter name under which you will later refer to the variable. E.g. a variable “INSTALLATION” will be accessible via the parameter $INSTALLATION in panels and queries. For this reason the name should not contain spaces or special characters. In fact, it is advised to use all capital letters with underscores as separators where needed. This will allow you to quickly identify variables e.g. in queries.
Type: | determines the options which can be selected for a variable. Common useful types are Query, Datasource, Textbox and Custom. See the example below for how to use each of these. Depending on what you select here the dialog may change in the following.

#### Example: Jungfrau Frame Rates

In the following we will use each of the dashboard variable options introduced above to display the last recorded input and output framerates of Jungfrau receiver device.

We start by creating a panel in an otherwise empty dashboard which simply refers to a single Jungfrau receiver device, HED_IA1_JF500K1/DET/JNGFR01 in HED directly:

To accomodate for the four Jungfrau detectors currently availabe at HED, we could either

- add all other detectors into the same panel, or
- create another three panels, for each detector.

We could then do the same for the other instruments with Jungfrau detectors, such as MID, FXE and SPB. Every time a detector is renamed or added, we would then adapt our panels.

Variables allow us to parameterise the dashboard and panels however and reduce this error-prone copy-paste-adapt work.

In an first attempt we create a Textbox which allows the user to enter the device id of the Jungfrau detector they are interested in. We already give a meaningful default value as an example. For this we create a variable DETECTOR:

In our panel, we can now refer to this variable via $DETECTOR. We thus adapt our queries to use the the variable as measurement name, rather than fixing it in the query itself:

We can now type a different device id in the text box Grafana created to enter the variable. However, this immediately highlights a down-side of the textbox approach. The text is free-form, and thus, errors can easily occur. If in case of our Jungfrau detector we neglect to adjust both indices in the name, e.g by typing HED_IA1_JF500K2/DET/JNGFR01, while it should be HED_IA1_JF500K2/DET/JNGFR02, no data will be found in the database:

It would thus be much better to restrict the input the user can give for the $DETECTOR variable to meaningful values only.

We do this by using the Custom variable type, which allows us to define a fixed set of options.

Since the only part of the same that changes is the numerical index, we shorthand the options to the numbers 1-4:

Note how we get a preview of the selectable options as the bottom of the dialog.

Since the variable $DETECTOR now only contains the numerical index and not the full measurement name anymore we have to slightly adapt out query:

The measurement field in the query now inserts the index at the correct locations: HED_IA1_JF500K${DETECTOR}/DET/JNGFR0${DETECTOR}. Note the ${VAR} syntax to refer to variables within static text.

While this approach is already much better in that it allows to select only values for the $DETECTOR variable which resolve to data in the database, it still has a few shortcomings: we will need to update our variable definition whenever a Jungfrau detector at HED is removed or added; furthermore, we cannot simply copy the panel to other instruments. Their naming structure will not match the HED names. The panel will also break if a Jungfrau detector is ever introduced at HED that does not strictly follow the HED_IA1_JF500K${DETECTOR}/DET/JNGFR0${DETECTOR} template we used, e.g. if it is located in IA2 instead of IA1.

Much better would be if we could create a variable which takes its options from the database itself, rather than us statically defining these. This we can do using the Query variable type:

Here we define a query on the HED database that lists us all MEASUREMENTS, i.e. device ids that match a specific regular expression: SHOW MEASUREMENTS WITH MEASUREMENT = /^.*/DET/JNGFR[0-9]+$/.

Let’s first look at the general InfluxQL syntax for listing measurements in a database. SHOW MEASUREMENTS will list all measurements. However, we know that the device ids and thus measurement names of Jungfrau detectors follow a certain pattern: they will be of class DET and thus contain /DET/ in their name, alongside the JNGFR identifier. We can thus qualify the measurements we are interested in using the WITH statement coupled with a regular expression that defines our naming contraints: SHOW MEASUREMENTS WITH MEASUREMENT = /^.*/DET/JNGFR[0-9]+$/.

Let’s have a closer look at the regular expression. In Influx (and Grafana) regular expressions are enclosed in slashes (/). The expression then defines the start of a string to be part of the name (^). While not strictly needed here, this is good practice to indicate, alonside the end of the string ($). We then allow any number of characters to match up to the /DET/ part, for which we neeed to escape the slashes (/) as they are to be interpreted literally in the expression. We then fix that /DET/ needs to be followed immediately by JNGFR, which in turn is followed by digits ([0-9]) of which there needs to be at least one (+). Afterwards we do not allow additional characters - the device id needs to end after a digit ($).

Note

More details on the SHOW MEASUREMENTS can be found here: https://docs.influxdata.com/influxdb/v1.8/query_language/explore-schema/#show-measurements. A good overview of regular expression syntax is available on the Python documentation: https://docs.python.org/3/library/re.html.

With the above changes the $DETECTOR variable will now contain the full measurement name again and will have options selectable which match the regular expression ^.*/DET/JNGFR[0-9]+$. If we add or remove a detector at HED these options will automatically update and be correct as long as the detector name minimally contains /DET/JNGFR followed by digits only at the end.

We adapt the query accordingly, as we can now use the $DETECTOR variable directly again:

We’ve now solved the problem of automatically updating the variable if Jungfrau detectors are added or removed in the HED topic. However, we still cannot easily copy our dashboard into a different instrument. Both in the query defining the options for the $DETECTOR variable and the queries populating our panel with data the HED topic is hard-coded.

To make our dashboards and panels reusable in other topics we now define a **Datasource*+ variable alongside the $DETECTOR variable. We name it INSTALLATION:

Here we have selected the Datasource type, and then defined the source type as InfluxDB. We’ve further used a regular expression to limit the options to the instrument topics. For this we assume the an instrument topic name will consist of exactly three capitalized alphabetical characters: /^[A-Z]{3,3}$/, indicated by the {3,3} restriction, which is {minumum length, maximum length}. There should be no characters before or after these three letters, hence the ^ and $ tokens at the beginning and the end of the regular expression.

Conveniently we can use the $INSTALLATION variable directly in the definition of the query determining the options of the $DETECTOR variable:

All that is left is to also make use of the variable in our panel queries. We can now select any of the instruments as INSTALLATION and any of their Jungfrau detectors as DETECTOR to be shown in our panel:

## Panels

In Grafana, panels are plots or tables which are displayed on dashboards.

Note

Depending on your access rights for a given folder you may not be able to execute or view some of the actions and features described in this section.

### XFEL Datasource Specifics

Panels are used to display so-called fields which belong to measurements. For Karabo logging, each device relates to a measurement and each parameter of the device is a field. For the latter, the field name consists of the parameter name with the type appended to it. This is so that Karabo types can properly be restored when reading back from the database, even in case of evolving schema on the Karabo side.

A paramter frameRateIn`on a device `HED_IA1_JF500K1/DET/JNGFR01 as shown in the following screenshot

will thus be represented in a measurement HED_IA1_JF500K1/DET/JNGFR01 under the field frameRateIn-FLOAT in InfluxDB and thus Grafana:

Since device name uniqueness is guaranteed for each Karabo topic, and measurement name uniqueness must be assured in InfluxDB, each Karabo topic stores its logging data in a dedicated Influx database named after the topic. In the example above this is HED.

### Data Type Support

All Slow Control Karabo data types are supported by the InfluxDB loggers.

However, Karabo has a few datatypes which are not represented well by InfluxDB native types, or have limitations in being displayed in Grafana. The below list indicates current support and limitations:

Floating Point: | the float and double data types are handled by the native floating point type of InfluxDB and will display as expected in Grafana.
Integer: | types are represented by the native integer type of InfluxDB. The will display as expected in Grafana. There is a minor exception in that Influx does not support uint64`(`unsigned long long) data types. We thus cast this type to the supported int64 type. This will lead extremely large numbers, which use the 63rd bit, being displayed negative in Grafana. This problem is foreseen to occur very rarely, if at all.
Boolean: | types are converted to 0 (false) and 1 (true) and display as such in Grafana
Strings: | are stored as strings and display as such in Grafana. Note that for strings the aggregate function set is greatly reduced in InfluxDB, e.g. you cannot aggregate strings to a mean or max value. However, counting the occurance of (distinct) strings is possible. Strings best display in the table display widged of Grafana.
Vectors: | are serialized into a base64-encoded string form. Their content is thus opaque to InfluxDB and Grafana. However, counting the number of distinct occurances can be useful in some scenarios, such as for the bunch pattern table.

### Creating Panels and Visualizations

Creating a panel and the available visualizations are well described in the Grafana Documentation: https://grafana.com/docs/grafana/latest/panels/add-a-panel/, and https://grafana.com/docs/grafana/latest/panels/visualizations/. Make sure to check the menu on the left of these pages for chapters with detailed information.

### Examples

#### Quick Inspection of a Vacuum Incident

On the morning of February 4th 2020 the SPB_EHC_VAC/VALVE/VALVE_ROUGH_1 which is part of the AGIPD vacuum system was found in an UNKNOWN state. To investigate we want to plot related pressure values from the archive.

Since initially we want to check what data might be useful we choose not to create a panel or even dashboard right away. Rather, we use the Explore feature of Grafana, which allows for ad-hoc investigations.

We thus click on the “Compass” icon in the menu, which opens an ad-hoc panel.

We choose SPB as data source as this corresponds to our Karabo topic. Since we are interested in the EHC component we look for a gauge there and select it as measurement. The pressure itself will be in the value-FLOAT field. Finally we adjust the time range to the period of interested, as should in the screenshot.

We now see the development of the pressure of SPB_EHC_VAC/GAUGE/GAUGE_FR_1. If we are interested in the other gauges tracking pressures in the EHC component, we could add more queries using the Add Query button. However, **using a Regular Expression* we can avoid this repetitive work.

Measurements can be given as regular expressions, so instead of SPB_EHC_VAC/GAUGE/GAUGE_FR_1 we can write /SPB_EHC_VAC/GAUGE/GAUGE.*/ which will plot the value-FLOAT field from all devices which start with SPB_EHC_VAC/GAUGE/GAUGE. Note how in InfluxDB a regular expression is enclosed in /. Also not that we need to escape the slashes in the device name, i.e. use /. Our plot will now look like

We now see that there were spikes in pressure and also that for a longer period in the night the vacuum system was in a state where no logging information was recieved. This might have to do with the observed UNNOWN state.

Hence, to recover when the detector powered down, we need additional information. We decided to check the logs of the power supplies which should trip in case of a vacuum incident.

To do so we click Add Query and add the MPOD device controlling the high voltage of AGIPD: SPB_IRU_AGIPD1M/PSC/HV. The interesting values are the sense voltages, so we select this as field from channel 0: channels.U0.measurementSenseVoltage-FLOAT. This already shows us some correlation between the pressure behaviour and the voltage. Especially, we can see that the detector tripped or was powered down around 21.00 on Feb. 3rd.

To verify we decide to plot voltage trends for all HV channels. Again, we could add more queries manually, but decide to use a regular expression instead. For this we switch into textual query mode by clicking on the pen icon. This allows us to edit the query we’ve previously defined through the grafical editor:

    SELECT mean(/.*measurementSenseVoltage-FLOAT/) FROM "SPB_IRU_AGIPD1M/PSC/HV" WHERE $timeFilter GROUP BY time($__interval) fill(null)

Here the important part is the regex in the mean`function, which follows the same pattern as we used for the pressure value. The regex is enclosed in `/, and via .* we allow any field to be evaluated which ends with measurementSenseVoltage-FLOAT.

We can now see that all channels exhibited similar behaviour at the same time. However, we also observe that the value ranges of pressure and voltage are too different to display well on a single y-axis. Rather, two axes would be beneficial. We cannot do this in the Explore view, but since we consider the panel useful for future events we decide to create a proper dashboard with panel.

#### Using Two Y-axes

In this example we convert the preliminary investigation of the previous example, Quick Inspection of a Vacuum Incident, into a panel on a dashboard and adjust it to have two y-axes. This will allow us to display in the same plot values with divergent y-values.

We start by creating a new dashboard in the Detector folder. We then add a New Panel on the following screen, and enter the two queries from the previous example. Setting the time period to Feb 4th again, we should get something like the following:

Our primary goal is to add a second y-axis to have a better display of pressure and voltages in the same plot. For this we scroll down the right Panel to Series overrides (https://grafana.com/docs/grafana/latest/panels/visualizations/graph-panel/#series-overrides). Here we can assign a separate y-axis to our pressure data. For this we identfiy the data which is to have its axis overwritten via a regular expression. We know the pressure device/measurement names will contain GAUGE, while the voltage measurements will not. Hence, /:*GAUGE.*/ is a suitable expression. We can then click on the + icon to add an override for the y-axis:

To further improve display, we make a few more changes: we set the line fill in the main options to 0 but override it for pressure with 4. Additionally, we add units to the Axes: Energy->Volt(V) for Left Y and Pressure -> Millibars for Right Y. Finally, we add $m to the ALIAS BY field of our queries. This will shorten the legend entries to the measurment name only (https://grafana.com/docs/grafana/latest/features/datasources/influxdb/#alias-patterns).

Our plot should now look similar to the following:

We could now parameterise the panel via Dashboard variable to e.g. make it useful for the MID AGIPD as well. See :ref:`db_variables`_ for an example on this.

#### Correlate two XGMS

In this example we correlate the intensities recorded by two XGMs in the same SASE. The data shown here is from an EPIX irradiation beamtime in August 2020. For this it was of interest how the SA1_XTD1_XGM and the HED_XTD6_XGM correlate in the photon energy they register per train. The panel we will be discussing in the following is available in General->XGM correlation and parameterised for all instruments (not all have two XGMs though). It looks like this for the time period we will evaluate in the example:

Let’s recreate it step by step. We start by adding the relevant queries (see examples above). Note that in the screenshot these are parameterised bia an $INSTRUMENT variable referring to the database, and regexes on $XGM1`and `$XGM2 variables referring to the measurements of the to-be-correlated XGMs.

The regex is necessary as the $XGM1/2 variable is defined as a query variable which shows all measurements matching an expression /.*DOOCS.*XGM/.

This would also match the _events and _schema internal measurements, which we reject by defining that there cannot be any characters before or after the variable’s content: /^$XGM1$/, where ^ is the start of the field entry and $ its end.

Note that currently we simply have two series in our plot. However, we would like to have their correlation, i.e. in terms of XGM1’s recorded energy with respect to XGM2’s. We can do this using Grafana`s Transform feature:

There are many different transforms to select from, which are documented here: https://grafana.com/docs/grafana/latest/panels/transformations/. Interesting for us is Add field from calculation which is described as use the row values to calculate a new field. We thus select this and the select Binary operation as Mode. We can now enter the operation as XGM1 / XGM2. Importantly, we select Replace all fields to hide the original data series and display only the calculated value:

#### Displaying String Fields - Karabo Device States

For string fields many of the aggregate functions are not defined. Consider e.g. what the mean value of a string should be. However, there are a few useful visualizations Grafana can provide for string fields, and here most importantly Karabo device states.

Displaying the current State of a device can be done via a query which orders by time and only retrieves the latest result, e.g.

    SELECT "state-STRING" FROM /.*PLC\/[A-Z0-9]+$/ ORDER BY time DESC LIMIT 1

will retrieve the current state of all PLCs in a database/Karabo topic. A good visualization option for this is the Stat graph:

To evaluate the number of state updates a device has in a given time period, i.e. to check if a digital output is “flickering”, we can evaluate the number (count) of discrete values. This is also useful to check how often a bunch pattern changes, where each pattern is stored in a string-encoded hash:

## Exporting Data

You can use Grafana to export data you are viewing into a comma separated value (CSV) file, which can be read in with most data anaylsis tools and environments.

In the panel containing your data click on the dropdown of the panel title:

This will open a context menu. You’ll find the export option by clicking Inspect->Data.

A panel on the right side should now open giving you export options:

In the default setting all data series contained in your panel will be output to their own column in the CSV file. The left-most column gives a timestamp in ISO format.

You can also select only individual series to be output:

or toggle the Apply panel transformations switch to output data any transformations produce. In the XGM correlation example shown here, this switch needs to be toggled to export the data plotted in the panel, as it is based on a transformation:

The CSV files generally then look like the following:

Such files can e.g. easily be imported in Jupyter via numpy or pandas:

    from dateutil.parser import parse
    import numpy as np
    import pandas as pd

    # import in numpy, converting ISO date time to timestamp
    d = np.loadtxt("XGM1 vs. XGM2-data-as-seriestocolumns-2020-09-11 10_27_05.csv",
                   skiprows=1, delimiter=",", converters={0: lambda x: parse(x).timestamp()})

    # import into a Pandas dataframe
    df = pd.read_csv("XGM1 vs. XGM2-data-as-seriestocolumns-2020-09-11 10_27_05.csv",
                     sep=',', header=0)

Note that in the pandas example time information is imported as string values.

Warning

Grafana has a timeout of 30 seconds on queries. Thus you might need to split large data series in multiple time periods if you want to export fine-grained long-term trends. However, consider using the InfluxDB inbuilt aggregate functions to calculated e.g. min, max, mean and standard deviation while binning data on larger time intervals.

### Reducing and Selecting Data For Export

Before exporting large time periods of data it is often worthwhile to use Grafana to narrow down times of interest for a given data series. For this statistical aggregation functions can be used, which are provided by InfluxDB itself. A list can be found here: https://docs.influxdata.com/influxdb/v1.8/query_language/functions/

Consider for instance a gauge in SPB. We want to narrow down such time intervals, which show sudden changes in pressure. At first we look at the mean value of the gauge over the last 6 months:

We observe that there are areas without data and a few spikes. However, the data covers a wide range of values, so we are not sure if we actually see all “points of interest”.

We can use aggregations to highlight sudden changes in value. In the example below we use the maximum non negative difference of subsequent values. The peaks are now much more visible:

In the General->Series Stats dashboard quite a few of these statistial functions are aggregated into a single dashboard. It is parameterised to easily select a device and expected parameter from the dashboard interface. Furthermore, the y-axis scale is logarithms further highlighting changes:

For our gauge we e.g. see that for Feb 20 there is an interesting behaviour of the pressure. We can now zoom into this day and then export this data much more fine grained:

# Indices and tables

- Index
- Module Index
- Search Page

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